Controlled optical add/drop multiplexer

FIELD: physics.

SUBSTANCE: invention is a method for a controlled selective adding/dropping a channel in a fibre-optic communication system with wavelength-division multiplexing of 2N channels whose optical frequencies can be adjusted, but the spectral interval Δv between neighbouring channels is contestant, through controlled optical add/drop multiplexers (70, 80, 90), which include multi-stage structures of differently connected optical filters ({75-i}, {85-i}, {95-i}), having devices for controlled adjustment of their transfer constants. The optical filters used are asymmetrical single-stage (20), two-stage (40) and/or multi-stage (60) Mach-Zehnder interferometers.

EFFECT: adding/dropping a desired channel from an optical signal by controlling spectral characteristics of filter stages of the multiplexer.

22 cl, 12 dwg, 1 tbl

 

The technical field

The invention relates to fiber-optic communication systems (hereinafter VOSS) with multiplexing, in particular to methods managed I/o channels, managed and reconfigurable optical multiplexers I/o channels (hereinafter referred to respectively as t-OADM and ROADM), and can be used in systems dense spectral multiplexing (hereinafter DWDM), and moderate spectral multiplexing (hereinafter CWDM).

Prior art

At the present time to increase throughput trunk, urban and local fiber-optic communication systems are widely used technologies multiplexing. There are dense wavelength seal - DWDM and moderate spectral seal - CWDM. The DWDM technology is used mainly in long-haul communication lines, and CWDM technology in urban and local communication systems.

The DWDM technology is characterized by extremely high bandwidth, but are very expensive. Standard on-grid wavelengths, entered the International Telecommunications Committee (hereinafter - the Standard ITU)provides the spectral interval between channels 200, 100, 50 or 25 GHz spacing in wavelengths of 1.6, and 0.8, 0.4 and 0.2 nm, respectively); already used the system with even more of you who akim (12,5 GHz) seal channels.

Compared with DWDM number of channels in CWDM systems, which can be missed on a single fiber, much less, as recommended by ITU spectral spacing between channels is 20 nm. Technique CWDM much easier to use and cheaper.

At the nodal points VOSS for I/o channels are commonly used optical multiplexers I / o (hereinafter OADM). They allow the line one or more channels and at the same time to enter the signal on the same wavelength with the new information. This significantly increases the efficiency of communication systems.

OADM c fixed frequency channels allow you to enter/display only a limited number of channels. Systematically increasing the bandwidth requirements of the communication systems and the use of new approaches require greater flexibility for such devices.

The use of dynamically reconfigurable or managed optical multiplexers I / o (respectively ROADM or t-OADM) removes these limitations by allowing you to enter/display the required channels at any time; moreover, t-OADM can also be used in systems for spectral multiplexing where the wavelengths of the channels can be reconstructed. Thus, ROADM and POADM provide the opportunity for efficient traffic management VOSS, increasing e the higher bandwidth communication systems.

Well-known specialists in the field of optical systems design ROADM is a device consisting of discrete components and including a demultiplexer, optical switches and multiplexer. A couple demultiplexer-multiplexer can provide a multi-stage structure on the interference filters, diffraction gratings or planar performed on so-called structured wiring (AWG). Optical switches are used for input, output and transmission channels, usually Electromechanical microswitches.

However, such a device is expensive, especially if the number of channels in the communication system is great. It is characterized by a large insertion loss and degradation of the optical signal. In addition, the optical switches are insufficiently resistant to the environment, such as temperature, vibration and other factors.

The main functional element of the t-OADM is tunable optical filter - selective device, in which the Central frequency (wavelength) of the spectral band can be dynamically reconstructed. There are many tunable optical filters, but most of them due to various reasons, ill-suited for use in t-OADM.

For example, acousto-optic tunable filter has a strong polarization dependence, which creates many practical problems. The Bragg filter is rebuilt mechanically or by means of the temperature, therefore, the speed of adjustment is relatively small, about a millisecond. Tunable filter based on Fabry-Perot interferometers are also not very good, because if it is rebuilt in a wide range, its spectral bandwidth narrow enough, if the spectral band is narrow, it may be reconstructed only in a limited range.

Tunable optical filter based on an unbalanced interferometer Mach-Zehnder (next - single-stage IMTS) is characterized by low optical insertion loss and low polarization dependence. Equipped with electro-optical device of a phase shift, it can provide maximum agility.

Specialists in the field of fiber-optic communication systems it is known that a multi-stage structure on the basis of the single stage of the EMC, with the number of steps 8 or 9, characterized by high selectivity and is sufficient to cover the full spectral band used in systems for spectral multiplexing. Therefore, such a tunable filter of all of the above is most suitable for use in t-OADM and ROADM.

Known tunable optical multiplexer in the ode-output (US 6795654 B2), having an input port, output port and the output port and including device that provides input signal containing multiple channels associated with the input port of the multi-stage structure of the optical filters each of which passes through itself odd or even channels and reflects the even and odd channels, respectively, a device that provides the transmission of the reflected channels to the output port and bypass all filters in the channel (output channel) in the outlet port. When this optical filter in each stage contains fiber interferometer of Mach-Zehnder interferometers with phase shift and a mirror to reflect the channels not transmitted by the interferometer of Mach-Zehnder interferometers. Device that allows the transmission of reflected channels to the output port and the input to add a new channel through the input port, resulting again entered the channel is skipped in the output port may include circulators.

Using a tunable multiplexer carry out the known method of selective input and output of the specified channel (US 6795654 B2), which consists in the selective transmission of the even or odd channels and reflection respectively odd or even channels, and this operation is repeated as many times as necessary to reflect all channels, in addition to asked you what the ode to the specified channel at the output port, combining the reflected channels in the output port, the input of an additional channel through the input port and combining it with the channels directed to the output port.

Diagram of one embodiment of such a multiplexer device 10 is shown in figure 1. The multiplexer 10 has an input port 11, an output port 12, an outlet port 13 port 14 input and includes three single stage of the EMC: 15-1, 15-2 and 15-3, formed with three pairs of fiber optic splitters {16-1, 16-2}, {16-3, 16-4} and {16-5, sheet 16-6} and, as the interference of the shoulders, connecting optical fibers {17-1, 17-2}, {17-3, 17-4} and {17-5, 17-6}. The path difference in the three interferometers consistently doubled during the transition to the next interferometer.

Each of these three single stage of the EMC 15-1, 15-2 and 15-3 selectively skips the odd or even channels and, with the help of fiber-optic reflectors 15-1-1, 15-2-1 and 15-3-1, reflects and directs back to even or odd channels, respectively. There are two circulator: circulator 18-1 associated with the input 11 and output 12 ports for input channels in the device and transmission of the reflected mirrors the channels in the output port, and the circulator 18-2 - deletion of the selected channels in the outlet port 13 and entering new channels through the port 14 instead of separated channels.

A three-stage structure provides the output of one channel on which tuplenie input 8 channels and enter the new channel instead of extracted. Managed elements 15-1-2, 15-2-2 and 15-3-2 phase shift set in one of the shoulders of each of the three interferometers 15-1, 15-2 and 15-3, respectively, used for the managed realignment of the spectral characteristics of these single stage of the EMC 15-1,15-2 and 15-3, and thus, for input/output of any of the 8 channels.

According to the patent (US 6795654 B2), in other proposed proposed single stage of the EMC to perform using "discrete" elements: beam splitters, mirrors, prisms, polarizers or advanced filters Liota. As an alternative to mirrors 15-1-1, 15-2-1 and 15-3-1 and circulators 18-1 and 18-2 can also be used for the transmission channels to the output port 12 additional structure of an optical filter on a single stage of the EMC.

The above known device allows input and output of any channel of the eight channels, which employ optical network. However, the known device has significant drawbacks.

Specialists in the field of optical communication systems it is known that the above-described structure, containing a large number of optical elements, is one stage of the EMC in fiber or discrete variants, reflectors and circulators, is very cumbersome and may not be reliable and stable in real terms, as one stage of the EMC is very sensitive to the conditions of the environment and the surrounding environment, to temperature, vibration and other impacts. Therefore, for the realization of devices such assignment required a different approach - an approach using integrated-optic technology.

It is also known that the spectral characteristics of single-stage of the EMC are not the ideal shape is non-planar vertices and slowly falling edges of the spectral bands using them in systems spectral multiplexing with a high density of channels can cause overlapping channels and poor insulation channels. In addition, the single-stage EMC contribute significant variance in the channels, which at a high transfer rate can lead to an increase in the pulse duration and thus to reduce bandwidth optical communication systems.

It is known that a much better spectral characteristics and the smaller you make the variance have two asymmetric EMC or asymmetrical multi-stage EMC (next - two-stage and multistage recognized, but these devices are not reversible and therefore cannot be used in the above-described multiplexer 10 input/output.

To enable the integrated optical implementation of a managed optical multiplexer I / o should reduce the number of optical elements and to exclude the medium and R is victory, as they are incompatible with the integrated optical technology. Reducing the number of optical elements, it is also useful from the point of view of reducing the cost of the device.

Thus, the creation of way managed I/o and managed optical multiplexer I / o, more simple in design decision that meets existing requirements for isolation channels and make dispersion and is suitable for integrated optical implementation is the actual problem. While it is desirable that the device have additional functionality that was as dynamic and flexible enough, that is provided in various applications the best ratio between performance and cost.

Disclosure of inventions

While the invention has been tasked to provide a method and device input/output of the desired channel from the optical signal by using a selection of channels of the optical signal by controlling the spectral characteristics of the filter speed multiplexer with ensuring the subsequent output of the desired channel, the transmission of unwanted channels, enter a new alarm.

The task was solved by the development according to the invention method, the controlled, selective I/in the water channel in the fiber optic communication system using wavelength division multiplexing 2 Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant, in which:

(a) supplied from the optical network multi-channel optical signal into an N-stage structure, in which each stage includes an optical filter having one input or two inputs and two outputs, made with the possibility managed to set the coefficients of transmission and characterized in the n-th step, when n=1, 2, ..., N, the frequency interval Δνn=2n-1Δν between adjacent extrema in the dependency ratios of the transmission frequency, and the optical filter in each stage, except the first, one input and one output connected respectively with one of the outputs and one input of the optical filter of the previous stage, while one input of the optical filter of the first stage is the input port of the N-stage structure, and one of the outputs of the optical filter of the last stage is the output port at N-stage structure;

(b) select the channel to be input/output;

(c) configuring the optical filter of each stage so that the transmission coefficient of the optical filter with input and output used in the connection of the optical filters described in (a), had a maximum value at the frequency of the selected channel;

(d) pass the multi-channel optical signal through the N-stage structure, and receive the selected channel at the output of the optical filter of the last stage, which output port at N-stage structure;

(e) enters the new channel on the optical frequency of the extracted channel, join a new channel, and all channels except extracted, and return the merged channels in the optical network.

Thus according to the invention it is advisable that when using optical filters having two inputs, enter the new channel carried through the input port of the N-stage structure, which is connected with the input of the optical filter of the last stage, is not used in the connection of the optical filters described in (a), the Association of the new channel and all channels except extracted, was carried out by connecting the output of the optical filter of each stage, except the first, is not used in the connection of the optical filters described in (a)with the input of the optical filter of the previous stage, is not used in the connection of the optical filters described in (a)and return the merged channels in the optical network produced through the output of the optical filter of the first stage, are not used in connection filters as described in (a).

In addition, according to the invention it is advisable that when using optical filters with one input, enter the new channel was carried out through one of the optical inputs of adder having N+1 inputs and one output, the Association but the CSO channel and all channels in addition to extracted, was carried out by connecting the output of the optical filter of each stage, not used in connection filters as described in a), with one of the inputs of the specified accumulator, through the output of the adder aggregated links returned in the optical network.

The task was solved by the development of high-precision optical multiplexer input/output for fiber-optic communication systems with wavelength division multiplexing 2Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant, according to the invention having one input port, one output port, one output port, one input port and including:

N-stage structure, containing in each stage one optical filter made with the possibility of a managed realignment transmission ratios characterized in the n-th step, when n=1, 2, ..., N, the frequency interval Δνn=2n-1Δν between adjacent extrema in the dependency ratios of the transmission frequency and having two inputs and two outputs;

controller to control the rebuilding of the transmission ratios of these optical filters.

Thus according to the invention is advisable to multiplexer input/output in the specified N-stage structure:

of optical fiber is ski filter of each stage, except for the first one of the inputs and one of the outputs was connected respectively with one of the outputs and one input of the optical filter of the previous stage;

- optical filter of the first stage to the other entrance was connected with the input port;

- optical filter of the first stage to the other one output was connected to the output port;

- optical filter of the last stage in the other output was connected to the output port;

- optical filter of the last stage in yet another sign was connected to the input port.

Thus according to the invention it is expedient that the multiplexer I/o optical filter stages N-stage structure was a single-stage and/or two unbalanced interferometers, Mach-Zehnder interferometers.

The task was solved by the development of high-precision optical multiplexer input/output for fiber-optic communication systems with wavelength division multiplexing 2Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant, according to the invention having one input port, one output port, one output port, one input port and including:

N-stage structure, containing in each stage one optical filter which has a capability-driven reorganizations is s transmission ratios characterized in the n-th stage, when n is 1, 2, ..., N, the frequency interval Δνn=2n-1Δν between adjacent extrema in the dependency ratios of the transmission frequency and having one input and two outputs;

- optical adder having N+1 inputs and one output connected to the output port;

controller to control the rebuilding of the transmission ratios of these optical filters.

Thus according to the invention it is expedient that the multiplexer input/output in the specified N-stage structure:

- optical filter of each stage except the last stage, one of the outputs was connected to the input of the optical filter in the subsequent stage and the other output is connected to one of inputs of the optical adder;

- optical filter of the first stage to its input coupled to the input port;

- optical filter of the last stage one output connected to another input of the optical adder, and another output connected to the output port;

- optical adder another input is connected to the input port.

Thus according to the invention it is expedient to optical filters N-stage structure was multi-stage unbalanced interferometers, Mach-Zehnder interferometers.

The task was solved by the development of high-precision optical multiplexer input/output is for fiber-optic communication systems with wavelength division multiplexing 2 Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant, according to the invention having one input port, one output port, one output port, one input port and including:

is connected between a first and second multi-stage structure comprising in each stage one optical filter made with the possibility of a managed setting their transmission ratios, with the first structure has N1steps, the second structure has N2stages and N1+N2=N;

- optical adder with N1+1 inputs and one output;

controller to control the reconstruction of the spectral characteristics of the optical filters of the first and second multi-stage structures.

Thus according to the invention it is expedient that the multiplexer input/output:

- optical filter in the first multistage structure had one input and two outputs and is characterized in n1the first step when n1=1, 2, ..., N1frequency interval Δνn1=2n1-1Δν between adjacent extrema in the dependency ratios of the transmission frequency;

- optical filter in the second multi-stage structure had two inputs and two outputs and is characterized in n2the first step when n2=1, 2, ..., N 2frequency interval Δνn2=2n2+N1-1Δν between adjacent extrema in the dependency ratios of the transmission frequency.

Thus according to the invention it is expedient that the multiplexer input/output:

in the first multi-stage structure of the optical filter of each stage, except the last one output was connected to the input of the optical filter in the subsequent stage, and the output was connected to one of inputs of the optical adder;

in the first multi-stage structure of the optical filter of the last stage one output was connected to one of the optical inputs of the adder, and the output was connected to one of inputs of the optical filter of the first stage of the second multi-stage structure;

the second multi-stage structure of the optical filter of each stage, except the first, one of the inputs and one of the outputs was connected respectively with one of the outputs and one input of the optical filter of the previous stage;

the second multi-stage structure of the optical filter of the first stage structure other output was connected to another input of the optical adder;

in the first multi-stage structure of the optical filter of the first stage to the other entrance was connected with the input port;

the second multi-stage structure of the optical filter lastly the tier one of the outputs was connected to the output port;

the second multi-stage structure of the optical filter of the last stage to the other entrance was connected to the input port;

- optical adder output was connected to the output port.

Thus according to the invention it is expedient that the multiplexer input/output optical filters of the first multistage multistage structure was unbalanced interferometers, Mach-Zehnder interferometers, and optical filters of the second multi-stage structure was a single-stage and/or two unbalanced interferometers, Mach-Zehnder interferometers.

Thus according to the invention it is expedient, in order to control the setting of the coefficients of transmission of optical filters contained electro-optical or thermo-optical device of the phase shift.

Thus according to the invention it is expedient that the multiplexers I/o was performed on the integrated optical technologies on a single chip.

In addition, according to the invention it is expedient that the multiplexers I/o input port, output port, output port and the input port were performed using optical fibers.

Thus, the above problem of creating a managed optical multiplexer I / o (t-OADM) is solved by the present invention, which uses a multi-stage structure of the optical Phil the TRS. As optical filters can be used in single stage, two stage and multi-stage MTS, containing the phase shift device and having one or two input ports and at least two output ports.

The way managed selective input/output of one channel of the multichannel optical signal according to the present invention in all embodiments managed optical multiplexer I / o according to the present invention, the optical filter of each stage, except the first filter stage, one input and one output connected respectively with one of the outputs and one of the outputs of the optical filter of the previous stage.

When transmitting multi-channel optical signal through a multi-stage structure in each filter is channel separation into two groups: one containing odd; the other the even-numbered channels, in one of the groups contains the channel to be input/output. The spectral characteristics of the optical filters are configured so that the group sent to the next stage, is always selected channel; as a result, the output of the filter of the last stage comes only one channel - select the channel input/output. All other channels, together with the newly introduced by the channel, are combined and sent to output the Noah port.

In one embodiment, t-OADM according to the present invention, which can be used in optical filters having two inputs and two outputs, the Association of the new channel and all channels except extracted, carried out by connecting one output of the optical filter of each stage except the first stage, with other, previously not used by the input optical filter of the previous stage, and returning the combined channels in the optical network produce not previously used the other output of the optical filter of the first stage.

In another embodiment, t-OADM according to the present invention, which uses optical filters with one input and two outputs, the Association of the input channel and the bypass channel is performed using an optical adder, the inputs of which are connected to the second outputs of all filters, and input port.

In the third embodiment, a managed optical multiplexer I/o according to the invention can be used in conjunction with optical filters with one input and two outputs, and optical filters having two inputs and two outputs, and a multiplexer consists of two multi-stage structures, one of which corresponds to the first variant t-OADM, and the second - the second option t-OADM. Combining noise channels in each of the two structures Ave is performed similarly to the Association, used in the first two variants of the device, and enter the new channel as in the first version.

Thus according to the invention as an optical filter with two inputs and two outputs, are single-stage and/or two unbalanced interferometers, Mach-Zehnder interferometers, as optical filters with one input and two outputs, used multi-stage unbalanced interferometers, Mach-Zehnder interferometers, and to manage the configuration of the transfer coefficients of the optical filters contain electro-optical or thermo-optical device of the phase shift.

In addition, it is essential that according to the invention offer the multiplexers were performed on the integrated optical technologies on a single chip.

A brief description of the drawings.

The invention is further explained in the description of embodiments of the method of controlled selective I/o channel in a fiber optic communication system using wavelength division multiplexing 2Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant according to the invention, with managed optical multiplexers I/o according to the invention, and the appended drawings on which is shown:

Figure 1 - the scheme is known managed about the optical multiplexer input/output;

Figa diagram of a known single-stage interferometer of Mach-Zehnder interferometers;

Fig.2b - conventional single-stage image of the EMC shown in Figa;

Figure 3 - dependence of the transmission coefficients from the optical frequency for the single-stage EMC shown in Figa;

Figa diagram of a known dual-stage of the EMC;

Fig.4b - conditional two-stage image of the EMC shown in Figa;,

Figure 5 - dependence of the transmission coefficients from the optical frequency for two of the EMC shown in Figa;

Figa diagram of a known multi-stage filter comprising three two-stage of the EMC;

Fig.6b - cosmetic multi-stage filter shown in Figa;

Fig.7 diagram of a managed optical multiplexer I/o according to the invention, containing a single stage of the EMC, with illustration work when submitting to the input port optical signal containing 8 CWDM channels;

Fig diagram of the controlled multiplexer I/o according to the invention, containing the modules of the EMC, with illustration work when submitting to the input port optical signal containing 64 DWDM channel;

Fig.9 is a diagram of a controlled multiplexer I/o according to the invention, containing a single stage, two stage and multi-stage MTS, with illustration work when applying to the input optical signal is a, contains 64 DWDM channel.

The best option of carrying out the invention

According to the invention the main element of the controlled multiplexer I/o is a well-known and commonly used in optics device unbalanced interferometer Mach-Zehnder or as agreed to call him, the single-stage EMC (M. Born, E.Wolf. "The Optic Base", Pergamon Press, Oxford, Fifth Oxford, Fifth Edition, 1975, pp.312-316; Mborn and Evolv. Principles of optics. TRANS. edited Gpotool.exe. M., Nauka, 1970, s-346).

The single-stage EMC is an interferometer with two singlemode shoulders and a pair of splitters at the two ends. The term "asymmetric" means that the arm length of the EMC obviously unequal. Differences in the length, temperature, or other parameters of the interferometer arms cause a phase shift for passing over the shoulders of the waves, which manifests itself in the interference of the output waves.

Embodiments of the single stage of the EMC using fiber optic splitters, beam splitters, mirrors, prisms, polarizers, and other elements discussed above in connection with the known. managed optical multiplexer input/output (US 6795654 B2).

On Figa shows a schematic depiction of the waveguide single-stage variant of the EMC 20, its a cosmetic for the purpose of describing the present invention shown in Figa. The device 20 is placed on one the first substrate 21, where the single-stage EMC 22 formed splitters 23 and 24 and the two arms 22-1 and 22-2 formed by waveguides of unequal length, 11and 12respectively. The coupling coefficients k1and k2accordingly splitters 23 and 24 are equal and divide the optical power 50/50. The single-stage EMC 22 has conclusions on the one hand, a and b, and conclusions on the other hand, c and d.

This single stage of the EMC 22 includes a shoulder 22-2 the phase shift device 25, which introduces additional phase shift φ in the phase of the passing waves and is a managed element that is used to adjust the spectral characteristics of the EMC.

The magnitude of the phase shift φ is controlled by thermo-optical or electro-optical effect by changing the value of electric current or voltage. Accordingly, the phase shift device 25 can be manufactured using thermo-optical material, such as silicone, or the electro-optic material such as lithium niobate (LiNbO3) or gallium arsenide. Such phase shift device known in the art spectral multiplexing as a tool to adjust the spectral characteristics of optical filters based on the EMC, and are also used in other devices, modulators and switches.

When entering through the first inlet and single radiation is offered by the power of the light intensity on the two outputs c and d can be expressed using transfer coefficients of the K ac(ν,φ) and Kad(ν,φ):

where D=2πnΔLν/c is the phase delay due to different optical length shoulder 22-1 and 22-2; ΔL=11-12; n is the refractive index of the material, ν is the optical frequency and C is the speed of light in vacuum.

Upon excitation via the second input b of the light intensity on the same outputs C and d can be represented using the transfer coefficients of the Kbc(ν,φ) and Kbd(ν,φ):

Considered at any frequency ν (or wavelength λ) coefficients of transmission (1)÷(4) be the spectral characteristics of single-stage of the EMC. As you can see, these spectral characteristics (1)÷(4) are periodic functions of the light frequency ν and wavelength λ and the difference of the lengths of the shoulder ΔL, the refractive index n and the phase shift φ.

For the health of a single stage of the EMC significant following properties:

- the distance between adjacent extrema Δν and Δλ in the spectral characteristics (1)÷(4) in units of optical frequency in units of wavelengths are respectively equal to:

- transfer coefficients of the (1)÷(4)corresponding to the optical transition radiation from one of the inputs a or b on the first c and second d outputs different is conducted in phase by π;

the transmission ratios when replacing the two indices do not change, that is,

Kad(ν,φ)=Kbc(ν,φ) and Kac(ν,φ)=Kbd(ν,φ);

- changing the value of the phase shift φ, it is possible to modify the spectral characteristics (1)÷(4)by sliding them along the axis of the frequencies (or wavelengths); this leads, in particular, when the change of the phase shift δφ=±π, inversion of the signals at the outputs;

the transmission ratios are not changed when changing the direction of signal transmission, i.e. single stage of the EMC is a reversible device.

In turn, from these properties it follows that when input single stage of the EMC optical signal containing multiple channels, frequencies (or wavelengths) which coincide with the position of the extrema in the dependency ratios of the transmission frequency (or wavelength), the signals are divided into two groups, which are displayed on different outputs. One group contains an odd channels, the other group - even channels, and in both groups the spectral interval between channels becomes two times greater than the input one stage of the EMC. Upon receipt of the same optical signal at another input, the odd and even channels at the outputs are swapped.

As one stage of the EMC is a reversible device, in another situation, when one input serves odd channels, and another input which are stated even channels, both groups of channels are combined into one optical flow with a dense arrangement of channels.

Devices that perform the function of the separation channels on odd and even channels and the inverse function combining odd and even channels into one stream, in foreign literature called interlibrary; in the literature there is no term for devices of similar purpose, in this text they are referred to as optical filters.

The distance between adjacent extrema Δν (or Δλ) in the spectral characteristics for the real single stage of the EMC should be formed at the stage of its manufacture by selecting the corresponding difference of the lengths of the shoulder L and refractive index n. Managed the reorganization provisions of the extreme values of the coefficients of transmission relative to the set of frequencies {νi} (or wavelengths {λi}) must be made using the appropriate adjustment of the phase shift φ at uses single stage of the EMC as an optical filter in the composition of any particular device.

Figure 3 shows the transfer coefficients of the Kac(ν,φ) and Kad(ν,φ) for a single stage of the EMC as a function of optical frequency, which, when the respective values of phase delay D and the phase shift φ is the distance between adjacent extrema 50 GHz can be thus, used to separate the odd and even channels with a spacing between adjacent frequency channels 50 GHz. Solid lines show the spectral dependence of the transmission coefficient Kac(ν,φ), in which one group of channels is odd channels is outputted from, the dotted lines show the spectral dependence of the transmission coefficient Kad(ν,φ), responsible for the output of the other channel groups - even channels on exit d.

As can be seen in Figure 3, the disadvantage of this optical filter is non-planar vertices and slowly falling edges of the spectral bands in a small spectral interval between channels may cause crosstalk between adjacent channels. Another well-known disadvantage is that when a large difference of the lengths of the shoulder ΔL make the variance can be very high. These shortcomings limit the possibility of using single stage of the EMC in the devices used in communication systems with wavelength division multiplexing channels.

A significant improvement in spectral characteristics of optical filter devices and systems for spectral multiplexing provide, as it is known (US 6782158), two of the EMC, which can be done using fiber optic splitters, beam splitters, mirrors, prisms, polarization application : the tori etc., and in the integrated optical form and contain this device phase shift.

On Figa shows a schematic depiction of the waveguide two-stage variant of the EMC 40, its conventional image shown in Fig.4b. In the device 40 uses three splitter 41, 42 and 43 with the coupling coefficients k1, k2and k3respectively. The device 40 is placed on a single substrate 46.

The first single stage of the EMC 44 is formed of two splitters 41 and 42 and the two waveguides 44-1 and 44-2 of unequal length, 144-1and 144-2respectively. The second single stage of the EMC 45 is formed of two splitters 42 and 43 and the two waveguides 45-1 and 45-2 of unequal length, 145-1and 145-2respectively. Phase delay D1=2πn(144-1-144-2)/λ and D2=2πn(145-1-145-2)/λ are linked by the relation: D2=2·D1.

In the EMC 44 and 45 are used, the phase shift device 47 and 48 made their phase shifts will denote by φ and φ, respectively. The two-stage EMC has conclusions on the one hand, a and b, and conclusions on the other hand, e and f.

The spectral characteristics of the two-stage EMC 40 easy to obtain analytically. For three splitters 41-1, 41-2 and 41-3, you must enter the matrix T(kifor (i=1, 2, 3), which relate the amplitude of light at the input and output parameters splitters:

and for the two single stage of the EMC 43 and 44 of the matrix T(D1) and T(D2):

Then the matrix bandwidth M(ν,φ,ϕ) are two of the EMC is determined by the product of the five matrices:

Since the coefficients of the two-stage gear of the EMC connect the optical output intensity from the optical intensity at the entrance for their definition, you should use expressions like:

From expressions (6)÷(9) can be obtained all the main features

two of the EMC. It is easy to check that two of the EMC at the input radiation through inputs a and b remains a device for splitting and merging odd and even channels. So, when applying the optical signal to the input and a two-stage IMTS channels will be divided into two groups containing one band - odd channels, and the other band - even channels. We note an important property, the remaining two of the EMC: when applying the same optical signal at another input, in Figa, groups with odd and even channels are swapped at the outputs e and f.

The distance between adjacent extrema Δν and Δλ in the spectral characteristics are also determined by the expressions (5), where ΔL is the path difference in the first stage of the two stage of the EMC 40, i.e. ΔL=144-1 -144-2. Still managed shift of spectral characteristics, now using two phase shifts φ and ϕ. To shift the spectral characteristics of the Kac(ν,φ,ϕ) and Kaf(ν,φ,ϕ) along the frequency axis by the value of δν, you must use the appropriate devices phase shift change of the phase φ and ϕ:

You can also check by using expressions (6)÷(9)that when the input signal through the outputs e and f is lost can be divided into odd and even channels and respectively combining odd and even channels. This is a consequence of the fact that the matrix (6) and (7) are non-switched. Thus, two of the EMC are not reversible devices - two ports a and b on the one hand can be used only as input, while the other two ports e and f on the opposite side - just as the weekend, and so two of the EMC, as noted above, may not be used in a known managed optical multiplexer input-output presented in figure 1.

Figure 5. the above transfer coefficients of the Kae(ν,φ,ϕ) and Kaf(ν,φ,ϕ) as a function of optical frequency for a certain stage of the EMC calculated by using expressions (6)÷(9). This stage of the EMC when the coupling coefficients k1=0.7854, k2=2.0944, k3=0.3218, the corresponding phase is americah D 1and D2and the phases φ and φ can be used as a 50 GHz optical filter to separate the odd and even channels with a spacing between adjacent frequency channels 50 GHz. Solid lines show the spectral dependence of the transmission coefficient KAC(ν,φ,ϕ), according to which when the input through the first input of a one group of channels (odd channels) is output to the first output e, the dotted lines show the spectral dependence of the transmission coefficient Kaf(ν,φ,ϕ), responsible for the output of the other channel groups (even channels) on the second output f.

As you can see, the two-stage EMC has a much better form of the spectral characteristics is close to rectangular, with a flat top and steep decline at the edges of the spectral bands. Therefore, two of the EMC used as the optical filter provides the best suppression of crosstalk and high isolation channels. However, make two of the EMC variance remains large, which limits its application as an optical filter in communication systems with high data transfer rate.

It is known that the situation can be changed for the better when using filters obtained by cascading two of the EMC. In one embodiment, such devices can be used two-stage the MC, having the same transmittance, but opposite in sign to the dispersion, the so-called complementary stage of the EMC. Complementarity is ensured by a certain ratio of the coupling coefficients k1, k2and k3in the elemental composition of the EMC (US 6782158 B2).

On Figa shows one variant of the multi-stage EMC 60, which can be used for separation of odd and even channels; conventional multistage image of the EMC (MZI-3) is shown in Fig.6b. The device 60 in the planar version hosted on the same substrate (chip) 61, has an input port g, the first output port p and the second output port k and consists of three two-MTS, which has a first input, a second input b, the first output and the second output f, while in the first stage used a two-stage EMC 62 type I, and in the second stage of the two stage of the EMC 63 and 64, both type I', i.e. with opposite signs of dispersion.

When the input signal through the input port g two of the EMC 62, as usual, divides the channels into two groups: in one group of odd channels, and the other is even; in the second stage of the EMC 63 skips the odd channels on their first e and then in the external first output port p, and the EMC 64 transmits the even-numbered channels on its output f and forth in the outer second output port k. As the dispersion stage of the EMC 62 and DV is cascadenik the EMC 63 and 64 have opposite signs, the resulting dispersion of multi-stage IMTS 60 is offset is zero or almost zero.

Unfortunately, the disadvantage of the multi-stage EMC is that when the input optical signal through the second input b of the two-stage of the EMC 62 groups containing odd and even channels, not just change seats on the two outputs of the EMC 63 and 64, as shown in other output than the former when the input optical signal through the input (outputs f and e are two of the EMC 63 and 64, respectively). This disadvantage does not allow you to use the modules of the EMC in the following first embodiment implementing a managed optical multiplexer input/output according to the present invention.

The first option is managed optical multiplexer input/output according to the present invention is intended for systems spectral seals with a wide spectral interval between adjacent channels, for example for CWDM systems. Diagram of the multiplexer 70 for this option is shown in Fig.7.

The multiplexer has one input port 71, one output port 72, one output port 73, one input port 74 and includes three optical filter 75-1, 75-2 and 75-3, forming a hierarchical structure. The whole device in a planar form fabricated on the same silicon substrate 76. Four port 71÷74 is made in videswebcam. Filters all three stages are interconnected with fiber optic cable-conclusions waveguides 77 formed on a silicon substrate.

Dynamic control of the multiplexer is carried out by adjustment of the spectral characteristics of the three filters 75-1, 75-2 and 75-3 feeding device phase shift contained in all three filters, the respective voltages. Management is done via the controller 78, which is connected with the optical filters electric bus 79.

As optical filters can be used single stage of the EMC according Figa or two of the EMC according Figa. The filters are connected so that each filter, in addition to the first filter 75-1, one input and one output connected respectively with one of the outputs and one of the inputs of the previous filter and the first filter 75-1 other input is connected to the input port 71 and the other output from the output port 72, and the last filter 75-3 connected by another input to the input port 74 and the other output from the output port 73.

Note that the connection of optical filters in the device 70 are not the only possible, and here is another connection of optical filters. The advantage of this connection is that in the planar device design 70 waveguides 77 not intersect with each other is m

Consider the case when the input of the multiplexer 70 receives 8-channel optical signal with a frequency spacing between channels Δν=2400 GHz (the average interval between channels Δλ≈20 nm). As in this example, the spectral spacing between the channels is large, the optical filters used single stage of the EMC.

To ensure the specified interval between channels Δν=2400 GHz, single-stage three of the EMC distance between adjacent extrema in spectral characteristics (transmittance) is set so that when you move to the next one stage of the EMC doubles: Δν75-1=2400 GHz, Δν75-2=4800 GHz and Δν75-3=9600 GHz.

Accordingly, the expression (5) the difference of the lengths of the arms in a single stage of the EMC is: ΔL75-1=41,6 μm, ΔL75-2=20,8 μm and ΔL75-3=of 10.4 μm (assuming n=1.5). The Central wavelengths of 8 channels at a given spectral interval between channels Δν can be located as follows: λ1=1608.5 nm, λ2=1588.3 nm, λ3=1568.4 nm, λ4=1549.0 nm, λ5=1530.0 nm, λ6=1511.5 nm, λ7=1493.5 nm and λ8=1475.8 nm.

Suppose that at some fixed values of the phase φ*75-1, φ*75-2and φ*75-3which we denote as {φ*n}for one of the waves, such as waves ν3, conditions etc the transmission from the input port 71 in the outlet port 73. Obviously, these conditions are to match the maximum values of the following transmission ratios of the three filters at a wavelength of λ3:

To better understand the operation of the device in question, it is necessary to describe more fully the spectral characteristics of the three optical filters 75-1, 75-2 and 75-3.

When installed, the distance between adjacent extrema ∆ F75-1, ∆ F75-2and ∆ F75-3(11) the transfer ratio To75-1ad(ν,φ*1for optical filter 75-1 has maximum values for odd waves ν1, ν3, ν5and ν7and the minimum for even waves ν2, ν4, ν6and ν8the transfer coefficient K75-2ad(ν,φ*2for optical filter 75-2 has a maximum for waves ν3and ν7and minimum values for waves ν1and ν5the transfer coefficient K75-3ad(ν,φ*3for optical filter 75-3 has maximum values for wave ν3and the minimum value for the wave ν7. It should also be borne in mind invariance of the coefficients of the single-stage transmission of the EMC when the permutation of subscripts.

So, mulitplexing signal, comprising 8 spectral channels comes from VOSS to the input port 71. Optical Phil is Tr 75-1 in accordance with its transmission coefficient K 75-1ac(ν,φ*1) sends waves ν1, ν3, ν5and ν7to the optical filter 75-2, and the waves ν2, ν4, ν6and ν8skips to the output port 72. Optical filter 75-2 in accordance with the gear ratio K75-2ad(ν,φ*2) sends waves v3and v7to the optical filter 75-3, and the waves ν1and ν5- back to the optical filter 75-1, which now held him when K75-1bc1φ*1)=K75-2bc(ν5,φ*1)=1 and appear in the output port 72. Optical filter 75-3 sends a wave ν3in accordance with the gear ratio K75-3ad3,φ*3in the output port 73, and a wave ν7when K75-3ac7,φ*3)=1 returns the first optical filter 75-2, and then this wave v7when K75-2bc7,φ*2)=1 passes to the optical filter 75-1, with whom she when K75-1bc7,φ*1)=1 is in the output port 72.

It is easy to trace the trajectory of the wave ν' (ν'=ν3)input via the input port 74. For this wave at successive passage through the three optical filter 75-1, 75-2 and 75-3 to the output port 72 of the values of the respective transmission ratios are all equal to unity: K75-3bc(ν',φ*3)=K75-2bc(ν',φ* 2)=K75-1bc(ν',φ*1)=1, and therefore wave ν' passes to the output port 72.

Thus, the connection of the second output optical filters 75-2 and 75-3 with one of the inputs of the previous filter allows you to organize the Association of newly introduced channel ν3and channels that do not contain the selected channel ν', and send them in the opposite direction to the first optical filter 75-1, whence they return to VOSS.

Consider now the operation of the device 70 in the dynamics, when any of the selected channel can be subjected to input/output. To do this properly change the values {φn} phase shifts for the three optical filters, using the expression (10). For example, to switch input/output neighboring wave ν4that should read as follows to change the phase shifts: δφ75-1=π δφ75-2=π/2 and δφ75-3=π/4.

Table 1 shows the changes of phase shifts {δφn}that need to be made for input/output of any of the 8 channels.

Table 1
The frequency channels of I/o and the corresponding changes of phase shifts {δφn}
The channel numberFrequency kanalowe/o Changes of phase shifts {δφn}
δφ75-1δφ75-2δφ75-3
1ν10
2ν2-½π-¼π
3ν3000
4ν4π½π¼π
5ν50π½π
6ν6π1½π¾π
7ν700 π
8ν8π½π1¼π

Note that in table 1 the changes of phase shifts {δφn} can be replaced by an equivalent {δφ'n}, such that δφ'n=δφn±2πn, where n=1, 2, ....

The second option is a managed optical multiplexer input/output according to the present invention is designed for DWDM systems. Diagram of the multiplexer 80 for this option are summarized in Fig. Let us assume that the input signal contains 64 channels, frequency channels correspond to the ITU-standard and have a spectral interval between the channels Δv=50 GHz.

The multiplexer has one input port 81, one output port 82, one output port 83, one input port 84 and includes six optical filters 85-1, 85-2, 85-3, 85-4, 85-5, 85-6, forming also a multi-stage structure. The multiplexer further comprises an optical adder 86, having seven inputs and one output. All six filters and the adder integrated on a single substrate 87. Four ports 81, 82, 83 and 84 made in the form of fibers. Connection filters with optical fibers, as well as all other connections are completed waveguides 88.

Dynamic control of the multiplexer is carried out by adjustment of the spectral features and advantages of the six filters 85-1÷85-6 when applying to the device a phase shift of all six filters of the respective voltages. Management is done via the controller 89, which is connected with the optical filters electric bus 89-1.

As the input signal spectral channels are much closer to each other, it requires the use of elements with higher characteristics, namely with better insulation channels, as well as to use a multiplexer at high transmission speeds - low dispersion. It should be noted that crosstalk in adjacent channels, as well as the introduced dispersion take place primarily in the filters of the first stages, where the spectral spacing between the channels at the entrance of a small, but very large differences between the lengths of the shoulders in the EMC and accordingly made a big variance. In subsequent stages the intervals between the channels become more and made the less variance, respectively, of the requirements for the optical filters in these stages can be reduced.

Therefore, in the present second embodiment is controlled optical multiplexer I/o according to the invention in the first three stages are used multistage MTS, shown in Figa, and in subsequent stages - two of the EMC shown in Figa. Obviously, in this embodiment, the multiplexer 80 is simpler and cheaper to manufacture than if it was performed only on mnogo the kick step of the EMC.

Optical filters are connected in series with each other so that the first output of one filter is connected to the input of another, the second output of each filter is connected to one of the optical inputs of the adder, the input of the first filter 85-1 is connected to the input port 81, the output of the last filter 85-6 connected to the output port 83, and an optical adder 86 to one input connected to the input port 84, and the output from the output port 82.

The distance between adjacent extrema in the spectral characteristics of six optical filters are also established so that during the transition to the next optical filter doubles: Δν85-1=50 GHz, Δν85-2=100 GHz, Δν85-3=200 GHz, Δν85-4=400 GHz, Δν85-5=800 GHz and Δν85-6=1600 GHz. Accordingly, the difference of the lengths of the arms of the interferometers in the first steps used multi-stage and two-stage of the EMC should be: ΔL85-1=2000 μm, ΔL85-2=1000 μm, L85-3=500 μm, ΔL85-4=250 μm, ΔL85-5=125 μm and ΔL85-6=62.5 μm.

Suppose that for one of the waves, such as wave v3at some fixed values of the phases {φ*n} and {ϕ*n} respectively in the first and second stages of a two-stage at Moscow art center, used in all six optical filters, conditions are similar to (11), which provides mileage wave ν3what about the route from the input port 81 to the output port 83.

The operation of the device 80 when these phases {φ*n} and {ϕ*n}, as follows. The input signal comes from VOSS to the input port 81, the optical filter 85-1 divides the channels into two groups - group odd waves ν1, ν3, ... ν63that are directed to the optical filter 85-2, and the group of even-numbered waves ν2, ν4, ..., ν64that are directed to the optical adder 86.

The process is repeated several times: optical filter 85-2 again divides waves and sends waves ν3, ν7, ..., ν59, ν63to the optical filter 85-3, and the waves ν5, ν9, ..., ν57, ν61the adder 86, and this continues up until the last optical filter 85-6, finally, in recent times will not share coming to him two waves ν3and ν35. The result is the wave of the ν3held in the output port 83, and all other 63 waves after passing through the adder 86 appear in the output port 82. Wave ν3entered via port 84, also comes to an output port 82.

When the multiplexer 80 in dynamic mode, i.e. for the input/output of any other waves, it is necessary in accordance with expressions (10) to change the values of the phases {φn} and {ϕn} for all used optical filters. As for the above-described multiplexer 70 (7), is a possible condition, when none of the waves is not displayed, and all are ignored in VOSS. The number of devices of the phase shift in the third embodiment, a multiplexer is much larger than in the first embodiment, however, the task of re-adjustment of phases {φn} and {ϕn} presents no fundamental difficulties.

Possible optical losses and varying levels of channels for noise waves can be compensated by using a conventional technique in DWDM optical amplifier and/or spectral equalizer.

A third option managed optical multiplexer input/output according to the present invention can also be used in DWDM systems spectral multiplexing. Diagram of the multiplexer 90, corresponding to the variant shown in Fig.9.

Let us assume that the input signal again contains 64 channels, frequency channels correspond to the ITU-standard and have a spectral interval between the channels Δν=50 GHz. Suppose also that the frequency channels in this case are held at their nominal values more strictly, and the data transmission speed is relatively low. So here are the requirements for isolation channels and make the dispersion used for the optical filter can be further reduced compared with the requirements in the above second embodiment, the implementation of managed optical multipl the xora input/output.

The multiplexer 90 has one input port 91, one output port 92, one output port 93, one input port 94 and includes six optical filters 95-1, 95-2, 95-3, 95-4, 95-5 95-6 and forming two multi-stage structure comprising the first structure of the two optical filter 95-1 and 95-2, and the second structure - four optical filter 95-3, 95-4, 95-5 95-6 and. Optical filters 95-1 and 95-2 are multistage MTS, shown in Figa, filters 95-3 and 95-4 - two of the EMC shown in Figa, and filters and 95-5 95-6 - single-stage the EMC shown in Figa.

The distance between adjacent extrema in the spectral characteristics of six optical filters are also established so that during the transition to the next optical filter doubles: Δν95-1=50 GHz, Δν95-2=100 GHz, Δν95-3=200 GHz, Δν95-4=400 GHz, Δν95-5=800 GHz and Δν95-6=1600 z.

The multiplexer 90 further comprises an optical adder 96 has 3 inputs and one output. All six filters and the adder integrated on a single substrate 97. Four port 91÷94 made in the form of fibers. Connection filters with optical fibers, as well as all other connections are completed waveguides 98.

The multiplexer 90 is a combination of the above first and second variants of the multiplexers according to the invention. The first two protected areas is ical filter 95-1 and 95-2 connected, as in the multiplexer 80, in series with the second connection of the outputs to the optical adder to form the first multi-stage structure. The second multi-stage structure with four optical filters is depicted in Figure 9 in the form of rows of optical filters; in this second structure of the optical filters are connected in the same manner as in the multiplexer 70, each filter except the first one of the inputs and one output connected respectively with one of the outputs and one of the inputs of the previous filter.

One of the inputs of the first optical filter 95-1 connected to the input port 101, one of the outputs of the last optical filter 95-6 connected to the output port 103 and one of the inputs of the last optical filter 95-6 connected to the input port 94. The third input optical adder is connected to one of the outputs of the optical filter 95-3, the output of the adder connected to the output port 92.

Dynamic control of the multiplexer is carried out by adjustment of the spectral characteristics of six filters 95-1÷95-6 when applying to the device a phase shift of all six filters of the respective voltages. Management is done via the controller 99, which is connected with the optical filters of all optical filters electric bus 99-1.

The operation of the multiplexer, the state is the future of the two multi-stage structures, optical filters, each structure is similar to that described above in the first and second embodiments of the multiplexer.

In the third embodiment, the implementation of managed optical multiplexer I/o in a more General case, the input/output of one channel from a 2Nchannel multiplexer must include two multi-stage structure of the optical filters: first multistage structure of the EMC (Figa) with the number of stages N1and the second structure of the optical filters on a single stage of the EMC (Figa) or/and two of the EMC (Figa) with a total number of stages in the second structure of N2.

The total number of optical filters must be N1+N2=N, the distance between adjacent extrema in the spectral characteristics of six optical filters must be installed also so that when you move to the next optical filter is increased in two times.

Separately, the number of single stage, two stage and multi-stage of the EMC should be selected based on the requirements of the spectral interval between channels Δν and data transfer rate. An important factor for the choice of optical filters used in both structures, can also be the cost of manufacture of the multiplexer.

Additional functionality of all three variants of the multiplexers according to astasia invention is the ability of these devices in mode, providing for one or more selected channels simultaneously output and transmission, without entering a new signal on the optical carrier output channels, all other channels, as usual, must be passed through to the output port.

We illustrate additional functionality on the example of the second variant of the multiplexer 80 (Fig). Let the input port 81 of act 32 of channel, such as wave ν1÷ν32and it is necessary to simultaneously display and skip the channel with the optical frequency ν3. In order to implement this mode (called mode "output/transmission"), it is necessary to keep the phase shifts {φ*n} and {ϕ*n}corresponding reviewed the occasion of the input/output wave ν3for all optical filters, except the last, and the value of the phase shifts φ6and ϕ6for the last optical filter 85-6 set such that for wave ν3ensured the division of optical power 50:50.

Similarly, if configured phases {φn} and {ϕn}, all six optical filters, you can ensure that this mode for any other wave. In order to perform mode "output/transmission for the two channels, for example with frequencies ν3and ν19needed to rebuild phase shifts for the filter 85-6, to execute the b division 50:50 for waves ν 3and ν19It is easy to continue the description of the relevant changes of phase shifts in optical filters to provide mode "output/transmission" other pairs of channels, and 4 or more channels.

In the described embodiments, a multiplexer according to the present invention uses a single concept. It consists in using the multistage structure of the optical filters based on asymmetric EMC. The optical filter of each stage, except the filter of the last stage connected to the input of the filter in the subsequent stage. For each optical filter coefficients of transmission carrier frequencies at the input channels have extreme values: for odd channels - minimum values for the even-numbered channels - maximum values, or Vice versa.

When transmitting multi-channel optical signal through a multi-stage structure in each filter is channel separation into two groups, one containing the odd and the other even-numbered channels, with one group contains the channel to be input/output. The spectral characteristics of the optical filters are configured so that the group is directed to the optical filter in the subsequent stage is always selected channel; as a result, the output port comes only one channel - SEL the p channel input/output.

All other channels together with newly introduced by the channel are combined and sent to the output port. The aggregation is performed using additional connections between filters using properties of their transmission ratios or using an optical adder. Thus, is controlled selective input/output of one channel and it provides the required spectral characteristics of the channels and minimum variance.

The principle of operation, characteristics and possible options for implementation of the present invention have been described above the examples of the use of appropriate devices in optical systems, in which the wavelengths of the channels consistent with ITU standards. Therefore, in these examples, the multiplexers functioned as reconfigurable optical multiplexers I/o - ROADM.

However, managed optical multiplexers I/o according to the present invention are more flexible and versatile than conventional ROADM, as can be used as a managed optical multiplexers I/o systems, in which optical wavelength channels are reconstructed, and therefore the necessary corresponding adjustment of the spectral characteristics of the multiplexers. The required restructuring of the spectral characteristics can be Le is to run using devices phase shift, posted in optical filters, in the same way as described in the examples.

As devices phase shift in all variants can be used as electro-optical devices and thermo-optical, while the electro-optical device of the phase shift can guarantee extremely high speed adjustment of the spectral characteristics of the multiplexer.

The use of integrated optical technologies for manufacturing seems to be the decisive factor for the multiplexers according to the present invention meet the requirements for devices of similar purpose, a large number of channels, resilience, high performance and other application in the design of devices unified model elements - single stage, two stage and/or multi-stages EMC, will allow the use of automated manufacturing operations, which, in turn, will provide high performance and relatively low cost of manufacture multiplexers.

The choice of one or another variant of the method of the managed selective input/output of one channel and managed optical multiplexer I/o according to the invention, as well as their optical fil the ditch, - single-stage, two-stage or multistage the EMC can be made with specific optical communication systems.

The examples explain the principle of operation, characteristics and possible options for the design of the present invention. Specialists in the field of fiber-optic communication systems should be obvious that within the framework of the present invention there may be other modifications and alternatives design managed optical multiplexers I/o according to the invention, is not beyond the scope of the claims.

Industrial applicability

The way managed selective input/output channels according to the invention and managed optical multiplexers I/o according to the present invention can be used in fiber-optic lines and communication systems with wavelength division multiplexing channels, including trunk lines, using DWDM technology, and in regional, urban and local communication systems using CWDM technology.

Managed optical multiplexers I/o according to the present invention can be implemented using existing integrated optical technologies.

1. The way managed selective I/o channel in a fiber optic communication system using wavelength division multiplexing 2 Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant, in which:
(a) supplied from the optical network multi-channel optical signal into an N-stage structure, in which each stage includes an optical filter having one input or two inputs and two outputs, made with the possibility managed to set the coefficients of transmission and characterized in the n-th step, when n=1, 2, ..., N, the frequency interval Δνn=2n-lΔν between adjacent extrema in the dependency ratios of the transmission frequency, and the optical filter in each stage, except the first, one input and one output connected respectively with one of the outputs and one input of the optical filter of the previous stage, while one input of the optical filter of the first stage is the input port of the N-stage structure, and one of the outputs of the optical filter of the last stage is the output port at N-stage structure;
(b) select the channel to be input/output;
(c) configuring the optical filter of each stage so that the transmission coefficient of the optical filter with input and output used in the connection of the optical filters described in (a), had a maximum value at the frequency of the selected channel;
(d) miss lots of the channel optical signal through the N-stage structure, and receive the selected channel at the output of the optical filter of the last stage, which output port at N-stage structure;
(e) enters the new channel on the optical frequency of the extracted channel, join a new channel, and all channels except extracted, and return the merged channels in the optical network.

2. The method according to claim 1, characterized in that when using optical filters having two inputs, enter the new channel is performed via the input port of the N-stage structure, which is connected with the input of the optical filter of the last stage, is not used in the connection of the optical filters described in (a), the Association of the new channel and all channels except extracted, is carried out by connecting the output of the optical filter of each stage, except the first, is not used in the connection of the optical filters described in (a)with the input of the optical filter of the previous stage, is not used in the connection of optical filters, as described in), and return the combined channels in the optical network is produced through the output of the optical filter of the first stage, are not used in connection filters as described in (a).

3. Way to claim 1, characterized in that when using optical filters with one input, enter the new channel is performed via one of the optical inputs of adder having N+1 inputs and one output, the Association of the new channel and all channels except the turn is established, carried out by connecting the output of the optical filter of each stage, not used in connection filters as described in a), with one of the inputs of the specified accumulator, through the output of the adder joint return channels in the optical network.

4. Managed optical multiplexer input/output for fiber-optic communication systems with wavelength division multiplexing 2Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant, having one input port (71), one output port (72), one port (73) o one port (74) input and including:
N-stage structure, containing in each stage one optical filter (75-1, 75-2, 75-3)made with the possibility of a managed realignment transmission ratios characterized in the n-th step, when n=1, 2, ..., N, the frequency interval Δνn=2n-1Δν between adjacent extrema in the dependency ratios of the transmission frequency and having two inputs (a, b) and two outputs (c, d);
a controller (78) for controlling the rebuilding of the transmission ratios of these optical filters (75-1, 75-2, 75-3).

5. The multiplexer input/output according to claim 4, characterized in that the specified N-stage structure:
optical filter (75-2, 75-3) of each stage except the first, one of the inputs (a) and one output (the) is connected, accordingly, one of the outputs (d) and one of the inputs (b) optical filter of the previous stage;
optical filter (75-1) first degree other input (a) connected to the input port (71),
optical filter (75-1) first degree other output (s) connected to the output port (72);
optical filter (75-3) the last stage of the other output (d) is connected to port (73) o;
optical filter (75-3) the last stage of the other input (b) is connected to port (74) input.

6. The multiplexer input/output according to claim 4, characterized in that the optical filter (75-1, 75-2, 75-3) of degrees N-step patterns are single-stage asymmetrical interferometer (20) Mach-Zehnder interferometers and/or two unbalanced interferometers (40) Mach-Zehnder interferometers.

7. The multiplexer input/output according to claim 4, characterized in that to control the setting of the transfer coefficients of the optical filters (75-1, ..., 75-6) contain electro-optical or thermo-optical device (25; 47, 48) of the phase shift.

8. The multiplexer input/output according to claim 4, characterized in that it is executed on the integrated optical technologies on a single chip.

9. The multiplexer input/output according to claim 4, in which the input port (71), output port (72), port (73) and output port (74) input performed using optical fibers.

10. Managed optical multiplexer input/output fiber optic connections is she using wavelength division multiplexing 2 Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant, having one input port (81), one output port 82), one port (83) o one port (84) input and including:
N-stage structure, containing in each stage one optical filter [85-1,...,85-6]made with the possibility of a managed realignment transmission ratios characterized in the n-th step, when n=1, 2, ..., N, the frequency interval Δνn=2n-1Δν between adjacent extrema in the dependency ratios of the transmission frequency and having one input (g or a) and two outputs (p, K or e, f);
optical adder (86)having N+1 inputs and one output connected to the output port (82);
controller (89) to manage the rebuilding of the transmission ratios of these optical filters [85-1, ..., 85-6].

11. The multiplexer input/output according to claim 10, characterized in that the specified N-stage structure:
optical filter [85-1, ..., 85-5] each stage except the last stage, one of the outputs (p or e) is connected to the input of the optical filter in the subsequent stage and the other output (k or f) is connected to one of inputs of the optical adder;
optical filter (85-1) the first stage of its input (g) is connected to the input port(81);
optical filter (85-6) the last stage of one output (f) is coupled to another input of the optical adder, and the other output (s) connected to the port (83) o;
optical adder (86) one input, not used in compounds, described above, is connected to the port (84) input.

12. The multiplexer I/o of claim 10, wherein the optical filters [85-1, ..., 85-6] N-step patterns are multi-stage unbalanced interferometers (60) Mach-Zehnder interferometers.

13. The multiplexer input/output according to claim 10, characterized in that to control the setting of the transfer coefficients of the optical filters (85-1, ..., 85-6) contain electro-optical or thermo-optical device (47, 48) of the phase shift.

14. The multiplexer input/output according to claim 10, characterized in that it is executed on the integrated optical technologies on a single chip.

15. The multiplexer I/o of claim 10, in which the input port (81), output port (82), port (83) and output port (84) input performed using optical fibers.

16. Managed optical multiplexer input/output for fiber-optic communication systems with wavelength division multiplexing 2Nchannels, optical frequency which can develop, but at this spectral range Δν between adjacent channels is constant, having one input port (91), one output port (92), one port (93) o one port (94) input and including:
interconnected first (90) and second (90b) multi-stage structure, with whom containing a series in each stage one optical filter [95-1, ... 95-6]made with the possibility of a managed setting their transmission ratios, with the first structure has N1steps, the second structure has N2stages and N1+N2=N;
optical adder (96), with N1+1 inputs and one output;
controller (99) to manage the reconstruction of the spectral characteristics of optical filters [95-1, ...95-6] the first and second multi-stage structures (90A, 90b).

17. The multiplexer I/o by item 16, characterized in that:
optical filter (95-1, 95-2) in the first multi-stage structure (90A) has one input (g) and two outputs (p, K) and is characterized by n1stage, when n1=1, 2, ..., N1frequency interval Δνn1=2n1-1Δν between adjacent extrema in the dependency ratios of the transmission frequency;
optical filter (95-3, ..., 95-6) in the second multi-stage structure has two inputs and two outputs and is characterized in n2stage, when n2=1, 2, ..., N2frequency interval Δνn2=2n2+N1-1Δν between adjacent extrema in the dependency ratios of the transmission frequency.

18. The multiplexer I/o by item 16, characterized in that:
in the first multi-stage structure (90A) optical filter (95-1) of each stage, except the last one output (p) is connected to the input (a) of the optical filter further STU is EIW, and the other output (k) is connected to one of inputs of the optical adder;
in the first multi-stage structure (90A) optical filter (95-2) the last stage of one output (k) is connected to another input of the optical adder, and the other output (p) is connected to one of inputs of the optical filter of the first stage of the second multi-stage structure (90b);
the second multi-stage structure (90b) optical filter (95-4, 95-5, 95-6) of each stage except the first, one of the inputs (a) and one output (f) is connected respectively with one of the outputs (e) and one of the inputs (b) optical filter of the previous stage;
the second multi-stage structure (90b) optical filter (95-3) first degree other output (f) is connected to another input of the optical adder;
in the first multi-stage structure (90A) optical filter (95-1) first-stage input (g) is connected to the input port (91);
the second multi-stage structure (90b) optical filter (95-6) the last stage of one of the outputs (C) is connected to port (93) o;
the second multi-stage structure (90b) optical filter (95-6) the last stage of the other input (b) is connected to port (94) input;
optical adder (96) output is connected to the exit port (92).

19. The multiplexer I/o by item 16, characterized in that the optical filter (95-1, 95-2) the first multi-stage structure is tours (90A) are multi-stage unbalanced interferometers (60) Mach-Zehnder interferometers, and optical filters (95-3, ..., 95-6) the second multi-stage structure (90b) are single-stage asymmetrical interferometer (20) Mach-Zehnder interferometers and/or two unbalanced interferometers (40) Mach-Zehnder interferometers.

20. The multiplexer I/o by item 16, characterized in that to control the setting of the transfer coefficients of the optical filters (95-1, ..., 95-6) contain electro-optical or thermo-optical device (25; 47, 48) of the phase shift.

21. The multiplexer I/o by item 16, characterized in that it is executed on the integrated optical technologies on a single chip.

22. The multiplexer I/o through P16, in which the input port (91), output port (92), port (93) and output port (94) input performed using optical fibers.



 

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