System and method for recording bragg grating

FIELD: laser and fiber optics.

SUBSTANCE: in accordance to invention, optical wave guide is heated up during recording of Bragg grating up to temperature, which depends on material of optical wave guide, and which is selected to be at least 100°C, but not more than temperature of softening of optical wave guide material, and selected temperature is maintained during time required for recording the Bragg grating.

EFFECT: increased thermal stability of recorded Bragg gratings.

2 cl, 3 dwg

 

The invention relates to the field of laser and fiber optics, and is intended for writing Bragg gratings in optical waveguides (optical fibers and planar waveguides).

The invention, in particular, can be used in the manufacture of optical lasers, fiber sensors of physical quantities (voltage sensors, temperature, acceleration, and other) and other fiber optic devices.

Currently there are several major systems and methods of writing Bragg gratings in optical waveguides, which are based on the exposure of the core of the optical waveguide (waveguide layer) ultraviolet radiation through the optical system, creating a certain interference pattern on the waveguide layer.

So, in Japan patent No. 71403311, G 02 F 1/01 describes how to write Bragg gratings in which the core of the optical waveguide effect of the coherent source of ultraviolet radiation through the optical system containing a phase mask.

The disadvantage of this method is the low thermal stability of the recorded Bragg gratings, which complicates the use of data grids in high power fiber lasers and virtually eliminates the use of data grids in the manufacture of temperature sensors, since the temperature of either the 100° With a Bragg grating written in this way, degrade (break down, float parameters).

In addition, as the core material of the optical waveguide in this way account, you can only use a certain set of photosensitive materials, which allow to obtain the Bragg grating when exposed to ultraviolet radiation. Thus the set of such photosensitive materials is rather limited.

Closest to the claimed invention in its technical essence and the achieved result is a method and system for writing Bragg gratings described in the patent US 4807950, G 02 F 1/01, selected as a prototype.

In this patent a system for writing Bragg gratings picscom waveguide contains a coherent source of ultraviolet radiation, an optical system for creating an interference pattern and a substrate for mounting the optical waveguide, the optical system for creating an interference pattern using a system with two intersecting coherent beams that are obtained from one source of ultraviolet radiation.

In this patent a method of writing a Bragg grating in an optical waveguide consists of the following operations:

- set the optical waveguide on the substrate;

- direct the beam from the source of ultraviolet radiation through the optical system at the core of the optical waveguide;

- formed by the optical system interference pattern on the optical waveguide, resulting in a record of the Bragg grating.

The disadvantages of this method and the recording system are the low thermal stability of the recorded Bragg gratings, which complicates the use of gratings in high power fiber lasers and virtually eliminates the use of data grids in the manufacture of temperature sensors, as well as a narrow set of photosensitive materials that can be used as the core material of the optical waveguide.

Bragg gratings recorded by this method, are formed due to the formation of stable defects in the atomic lattice of the glass (breakage of chemical bonds between the atoms of matter core), which leads to increased absorption and, consequently, the refractive index of the material in the irradiated area. Also in waveguide systems (optical fibers, waveguides) are present tension between the core and the shell, which are removed in the areas of ultraviolet irradiation, which also leads to the formation of a periodic structure. In the literature these lattices are called type 1 and type 2A, respectively. When raised the th temperature decomposition induced defects and stress relaxation, which leads to the collapse of the grid.

The present invention is a system and method of writing Bragg gratings in optical waveguides, allowing to expand the range of materials volnovatsa core of the optical waveguide, suitable for recording with a significant increase in thermal stability of the recorded Bragg gratings.

The problem is solved by creating a system of writing Bragg gratings, which contains coherent source of ultraviolet radiation, an optical system for creating an interference pattern, an optical waveguide substrate for mounting the optical waveguide and the heating element, which is configured to heat the optical waveguide to the temperature record of the Bragg grating, which is chosen not less than 100°s and not higher than the softening temperature of the material of the optical waveguide, with the optical system is located between the source of ultraviolet radiation and an optical waveguide.

For operation of the system is essential to the quality of the optical waveguide include an optical fiber, a planar waveguide or any similar waveguide.

For operation of the system it is important that as a coherent source of ultraviolet radiation it contains IP the source, selected from the group comprising a pulsed laser and ultraviolet range, permanent laser ultraviolet range.

To implement the system, it is important that in order to obtain an interference pattern in the optical system can be used in the phase mask.

As an optical system for creating an interference pattern recording system of the Bragg grating may contain the divisor of the laser beam, a set of mirrors or an interferometer loida.

It is important to note that there are many variants of realization of the optical system, whose main task is to obtain the interference pattern. The system may also contain a set of lenses, which main task is to increase the power density of the radiation.

To implement the system, it is important that the substrate and the heating element can be combined into a single element.

For the best functioning of the system it is essential that it can contain a stabilizer temperature of the heating element.

To control the functioning of the system it is essential that it can contain a spectrometer connected to the optical waveguide to control the recording quality of the Bragg grating in the optical waveguide.

The problem is solved by creating the recording method of the Bragg grating, which form the flow of wheretogo ultraviolet radiation, modify it according to the given optical system, and form an interference pattern on the optical waveguide, write Bragg gratings with a period equal to the period of the interference pattern, thus writing Bragg gratings produced in thermally pre-treated optical waveguide, which is heated prior to entry through the heating element to a certain temperature record of the Bragg grating, which is determined depending on the material of the optical waveguide and which for each material of the optical waveguide is in the range not lower than 100°s and not higher than the softening temperature of the material of the optical waveguide during the time required for writing Bragg lattice, the temperature of the optical waveguide is maintained within the range of not lower than 100°s and not higher than the softening temperature of the material of the optical waveguide.

For the operation method, it is essential that as an optical waveguide was chosen optical fiber, a planar waveguide or any similar waveguide.

To implement the method, it is important that the interference pattern can be created by using an optical system containing a phase mask.

For the operation method, it is important that the interference pattern can be create is by using an optical system with a divider of the laser beam and mirrors, or by using an interferometer loida.

To implement the method, it is desirable to heat the optical waveguide was produced by the contact method.

It is also possible to produce heating of the optical waveguide contactless convection method.

For the operation method, it is essential that the temperature record of the Bragg grating can be stabilized in the write period of the Bragg grating.

To implement the method it is preferable that the temperature record of the Bragg grating set in the range from 200 to 800°for waveguides, the core or the shell of which is made on the basis of quartz glass with addition of substances selected from the group comprising at least one of the following substances: oxides of germanium, aluminum oxide, phosphorus oxide, boron oxide, tin oxide, fluorine, arsenic oxide, gallium oxide.

To implement the method, it is important that the temperature record of the Bragg grating set in the range from 200 to 600°for waveguides, the core or the shell of which is made on the basis of silicate glass with addition of substances selected from the group comprising at least one of the following substances: lithium oxide, sodium oxide, potassium oxide, rubidium oxide.

The technical result of the invention is to expand the range of materials volnovatsa core of the optical waveguide suitable for recording the simultaneous significant increase in thermal stability of the recorded Bragg gratings, due to the heating of the optical waveguide before recording through the heating element to a certain temperature record of the Bragg grating.

For a better understanding of the present invention the following is a detailed description with the appropriate drawings.

Figure 1 - diagram of the formation of the Bragg grating in the waveguide due to the diffusion waveguide material (for example: SiO2+GeO2in the shell (e.g. SiO2).

Figure 2 - block diagram of the recording system of the Bragg grating in an optical waveguide using a phase mask according to the invention.

Figure 3 - block diagram of a system for writing a Bragg grating in an optical waveguide by using the interference of intersecting beams according to the invention.

The introduction of the element carrying out the heating of the sample during irradiation, leads to other mechanisms of formation of Bragg gratings. Education lattice is due to the stronger diffusion of the core material of the waveguide (waveguide layer 1) in the shell 2 in the zone of maximum interference pattern 3 than in the zone of minimum 4 (figure 1). This is possible by reducing the viscosity of the material, and also due to the fact that ultraviolet radiation in this case is the activator diffusion due to their ability to break chemical bonds. The main effect occurring during Zap the si Bragg gratings claimed process, is increased diffusion at the interface of two media, exposed to radiation with increasing temperature these environments.

In solids diffusion associated with the frequency of the gap and restore the links under the action of temperature, radiation and other Frequency gap and restore the chemical bonds per unit volume can be written by the formula:

νbit=C1n0+n0α0exp(σhνLAZ-E)/kT}ILAZthat νreset=C-1nfree- in the irradiated area;

ν*bit=C1n0that ν*reset=C-1nfreein non-irradiated area,

where C1With-1- the rate constants of forward and reverse reactions, temperature-dependent according to the law of Arrhenius equation, n0nfree- concentration of integers and dangling bonds, νLAZ, ILAZthe frequency and intensity of laser radiation, E is the energy bandgap, α0exp(σhνLAZ-E)/kT) is the absorption coefficient at the edge of the area of fundamental absorption (Urbach rule for crystalline environments, α1exp(hνLAZ/E+T/T0- for glassy).

In the stationary case, balance νbitresetand for difference frequency in irradiated and non-irradiated areas received:

ν-ν*=n0α0exσ (hνLAZ-E)/kT)ILAZ.

As you can see, this difference increases exponentially with increasing temperature of the material. This expression is true for the case of single-photon absorption at constant irradiation, but it is easy to see that the resulting pattern from the temperature does not change with the transition, for example, multiphoton process and pulsed laser radiation.

Expanding the range writable arrays of materials is due to the fundamental mechanism of their formation. All materials used in optical waveguides, are electrical insulators and are forbidden zone (transparency), which is limited in the shortwave region of the region e of the fundamental absorption region of the phonon absorption in the long wavelength region. The irradiation of such material by radiation with a wavelength that falls in the area of fundamental electronic absorption in the material is observed break ties.

Heating of the waveguide has the following advantages:

a). Heating of the waveguide when writing gratings allows painless significantly increase the intensity of the irradiation. Increasing the irradiation intensity to raise the frequency gap in the irradiated without heating the irradiated structure will only lead to the destruction of the material. The most used in volnovodnoi optics materials are low at room temperature the rate constant for the reverse reaction C -1. This leads to the fact that under intense irradiation, the concentration of nfreemay exceed a critical value, after which comes the irreversible destruction of the atomic mesh material. All of this can be attributed for the case of decreasing the wavelength of the irradiating radiation.

b). Heating of the waveguide when writing leads to decrease the viscosity of the membrane and increase its absorption. Consider a specific structure: Germano-silicate optical fiber with a cladding of pure silica glass. Germano-silicate core has a much greater absorption in the ultraviolet range than pure quartz sheath. Irradiation at room temperature leads to intensive processes in the core, but a weak effect on the shell, i.e. the boundary between the core and the shell remains permeable for atoms Germany. The structure is heated by irradiation leads to a decrease in the viscosity of the shell due to direct heating, the increase of absorption of the shell due to the shift of the edge e of the fundamental absorption.

c). Increases the use efficiency of incident radiation due to the shift of the edge e of the fundamental absorption.

For the case of waveguide systems based on silica glass, the application of heat should lead to even greater effect, so is it at room temperature under irradiation in the volume of glass formed stable ties (vacancies) in the core, and in the shell (νbit≠νreset), who do not participate in the diffusion process. When radiation hard high intensity ultraviolet perhaps even the destruction of the irradiated structure.

Considered the frequency of rupture and restoration of relationships is only one of the factors that affect the diffusion coefficient. Another factor is the coordination number of the atom. Under equal conditions the atom with a higher coordination number, has a smaller diffusion coefficient, but recorded it lattices have the best thermal stability.

The present invention is intended primarily for optical fibers and waveguides, based on the silicate glass and multicomponent oxide glasses. The invention can also be used to write gratings in optical waveguides based on chalcogenide glasses (BaF2CaF2, ...). The heating temperature of the optical waveguide for writing Bragg gratings depends on the composition of the waveguide and lies above the temperature of formation of stable defects under the action of radiation and below the softening temperature Tgthe main material. For each composition of the waveguide and conditions of the irradiation temperature can be determined experimentally once. For waveguides based on the quartz glass with the German-silicate core is nd the optimum range 200-600° C.

Greater than the irradiation without heating, the dose and the irradiation intensity required for writing gratings, is compensated for by the advantages of heating described above in paragraph (a).

The invention uses an additional heating element 5, carrying out the heating volnovatsa structures (optic fiber, planar waveguide) in the system for writing Bragg gratings as using phase masks (Figure 2), and using the interference of intersecting coherent beams (Figure 3).

Write the Bragg grating is carried out using ultraviolet laser radiation 6 (2, 3). The radiation from the source passes through the phase mask 7 which form the interference pattern. Interference pattern superimposed on the substrate 8 with the waveguide 9, which is in physical contact with the heating element 5 (Figure 2). It is important to note that when calculating the parameters of the phase mask 7 is necessary to consider heat and the change of refractive index on temperature. It is important that the temperature of the heating element 5 is stabilized, for example, by means of the stabilizer 10 temperature for the best optical quality of the recorded Bragg gratings.

Figure 3 presents the block diagram of the system in which the interference pattern formed by two intersecting coherent the different beams, which are formed at the output of the divider 12 and one of which is directed by the mirror 13. To control recording in an optical fiber using the spectrometer 11.

Each of the above schemes can be used for recording in planar waveguides and optical fibers.

Consider a specific example of application of the method for writing Bragg gratings in optical fibers based on silica glass core alloy 10 mol.% Germany at the wavelength of 1.55 μm. To record using a pulsed ArF excimer laser with a wavelength of 193 nm that falls in the region of fundamental absorption. The radiation density per pulse of 500 MJ/cm2in the zone of location of the fiber. Total dose is more than 50 kJ/cm2.

The phase mask 7 press to purified from polymer fiber 9 which, in turn, pressed against the heating element, the clerk is also the substrate. The heating element 5 has a temperature of 300±1°supported by the temperature stabilizer 10 with feedback. The process of writing the Bragg grating is controlled by the spectrometer 11.

Although the above embodiment of the invention has been set forth to illustrate the present invention, the experts it is clear that various modifications, additions and substitutions, without departing from the scope and meaning of altoadige of the invention, disclosed in the accompanying claims.

1. The system of writing Bragg gratings containing coherent source of ultraviolet radiation, an optical system for creating an interference pattern, an optical waveguide substrate for mounting the optical waveguide and the heating element, which is configured to heat the optical waveguide to the temperature record of the Bragg grating, which is chosen not less than 100°and not higher than the softening temperature of the material of the optical waveguide, with the optical system is located between the source of ultraviolet radiation and an optical waveguide.

2. The system according to claim 1, characterized in that the optical waveguide contains an optical fiber, a planar waveguide or any similar waveguide.

3. The system according to claim 1, characterized in that as a coherent source of ultraviolet radiation it contains a source selected from the group comprising a pulsed laser and ultraviolet range, permanent laser ultraviolet range.

4. The system according to claim 1, characterized in that the optical system to generate an interference pattern it contains the phase mask.

5. The system according to claim 1, characterized in that the optical system to generate an interference pattern on the and contains the divisor of the laser beam and a set of mirrors or an interferometer loida.

6. The system according to claim 1, characterized in that the substrate and the heating element is integrated into a single element.

7. The system according to claim 1, characterized in that it contains the stabilizer temperature of the heating element.

8. The system according to claim 1, characterized in that it contains a spectrometer connected to the optical waveguide to control the recording quality of the Bragg grating in the optical waveguide.

9. The way you write Bragg gratings, in which form the flow of coherent ultraviolet radiation, modify it according to the given optical system, and form an interference pattern on the optical waveguide, write Bragg gratings with a period equal to the period of the interference pattern, thus writing Bragg gratings produced in thermally pre-treated optical waveguide, which is heated prior to entry through the heating element to a certain temperature record of the Bragg grating, which is determined depending on the material of the optical waveguide and which for each material of the optical waveguide is in the range not lower than 100°s and not higher than the softening temperature of the material the optical waveguide during the time required to write the Bragg grating, the temperature of the optical volkovaddict within not less than 100° With and not higher than the softening temperature of the material of the optical waveguide.

10. The way you write the Bragg grating according to claim 9, characterized in that the optical waveguide is chosen optical fiber, a planar waveguide or any similar waveguide.

11. The way you write the Bragg grating according to claim 9, characterized in that the interference pattern created by the optical system containing a phase mask.

12. The way you write the Bragg grating according to claim 9, characterized in that the interference pattern created by the optical system with the divider of the laser beam and mirrors, including using an interferometer loida.

13. The way you write the Bragg grating according to claim 9, characterized in that the heating of the optical waveguide produced by the contact method.

14. The way you write the Bragg grating according to claim 9, characterized in that the heating of the optical waveguide to produce contactless conventional method.

15. The way you write the Bragg grating according to claim 9, characterized in that stabilize the temperature value write Bragg gratings in the write period of the Bragg grating.

16. The way you write the Bragg grating according to claim 9, characterized in that the temperature record of the Bragg grating set in the range from 200 to 800°for waveguides, the core or the shell of which is made on the basis to arciaga glass with the addition of substances selected from the group comprising at least one of the following substances: oxides of germanium, aluminum oxide, phosphorus oxide, boron oxide, tin oxide, fluorine, arsenic oxide, gallium oxide.

17. The way you write the Bragg grating according to claim 9, characterized in that the temperature record of the Bragg grating set in the range from 200 to 600°for waveguides, the core or the shell of which is made on the basis of silicate glass with addition of substances selected from the group comprising at least one of the following substances: lithium oxide, sodium oxide, potassium oxide, rubidium oxide.



 

Same patents:

FIELD: optical tool-making industry, possible use for building devices for spectral filtration of optical radiations, for example, optical filters of adjustable wave length, monochromators.

SUBSTANCE: method includes selecting substances being in optical contact and forming interface with negative derivative of dependence of angle of full internal reflection and wave length in optical more dense environment and using two pairs of optical environments for filtration of radiation. During reflection of polychromatic beam from interface of environments with positive derivative of dependence of full internal reflection angle and wave length, spectral components with wave length greater than given threshold are removed from the beam, and during reflection of polychromatic beam from interface of environments with negative derivative of dependence of full internal reflection angle and wave length, spectral components with wave lengths less than given threshold are removed. Plane angle, within limits of which a beam of source radiation expands in plane, wherein optical axes of falling radiation beam and radiation beam being reflected from interface of environments are located, may be limited by calculated value, determined on basis of required spectral resolution.

EFFECT: production of adjustable band filter with controllable pass band.

3 cl, 5 dwg

Optical film // 2297021

FIELD: optics.

SUBSTANCE: optical film includes array of elements and external cover, made of optical transparent material. Each element consists of at least one truncated pyramid and one non-truncated pyramid, positioned one above another so that base of the lowest truncated pyramid serves as base of the element, and upper cut of each truncated pyramid serves as base for higher pyramid, and the highest pyramid is made non-truncated. In each element corners at vortices of at least two pyramids are not equal to each other, also bases of elements are adjacent, forming a surface, while all elements are positioned on one side of given surface. External material covers sides of pyramids, while refraction coefficient of material of each pyramid is less than refraction coefficient of external material.

EFFECT: improved reflecting capacity of film.

10 cl, 6 dwg

FIELD: optical instrument engineering.

SUBSTANCE: device has to multiplayer electro-optic structure, which is formed by film of nematic liquid crystal (NLC) sensitized by photosensitive complex with charge transfer on base of system, which has to be photosensitive pyridine fullerene-structure. To orient molecules of LC the orienting coating is used made on base of film of non-photosensitive polyimide.

EFFECT: increased speed of operation of modulator.

2 dwg, 1 tbl

FIELD: measuring technique.

SUBSTANCE: electro chromic device has first substrate, which has at least one polymer surface, ground primer coat onto polymer surface, first electro-conducting transparent coating onto ground primer coat. Ground primer coat engages first electro-conducting coating with polymer surface of first substrate. Device also has second substrate disposed at some distance from first substrate to form chamber between them. It has as well the second electro-conducting transparent coating onto surface of second substrate applied in such a way that first coating is disposed in opposition to second one. At least one of two substrates has to be transparent. Device also has electrochromic medium disposed in chamber, being capable of having reduced coefficient of light transmission after electric energy is applied to conducting coatings. Electrochromic medium and ground primer coat are compatible.

EFFECT: simplified process of manufacture; cracking resistance.

44 cl, 1 dwg

FIELD: optical modulation of radiant flux.

SUBSTANCE: method of modulation is based upon formation of radiant flux by means of radiator, on direction of radiant flux of radiator onto reflection modulator and upon influence of reflected radiant flux onto receiver. Model of selective gray body is used as radiant flux radiator. Volumetric body with reflecting faces is used as reflection modulator, which body is mounted for rotation about its own axis. Oscillating change in value of speed of rotation of volumetric body and/or change in angle of slope of axis of rotation of volumetric body is carried out.

EFFECT: improved probability of irradiation of receiver.

4 cl, 1 dwg

FIELD: matrix display devices.

SUBSTANCE: device consists of a set of display elements compiled into a matrix; every element contains display pixel connected to a switch. Every display element also contains addressable trigger with output connected to switch control input. Addressable trigger has row and column address input.

EFFECT: creation of working mode, in which some display elements are activated on first refresh frequency, and the other display elements are activated on the second refresh frequency, which is less than first refresh frequency, by selective display elements addressing.

20 cl, 4 dwg

FIELD: indication equipment.

SUBSTANCE: element contains three serially positioned liquid-crystalline cells, inlet mask with slits, raster capacitor, raster objective, outlet mask with slits, position of which is synchronized with position of slits of inlet mask and considers distance from liquid-crystalline layer to slits of outlet mask. In each one of three cells one of three primary colors is formed due to electrically controllable diffraction grid, formed in liquid-crystalline layer when control voltage is fed onto it.

EFFECT: element has high brightness and independent, spectrally clean primary colors.

1 dwg

FIELD: measuring equipment.

SUBSTANCE: optical heat transformer includes base of body with optical unit positioned therein, transformer of heat flow and consumer of heat flow in form of thermal carrier. Optical unit consists of optical heat source and reflectors of coherent heat flows and concentrator - generator of coherent heat flow in form of two collecting mirrors and a lens, positioned on different sides of source, with possible redirection of coherent heat flow for interaction with transformer of heat flow with following transfer of heat flow.

EFFECT: decreased energy costs.

1 dwg

FIELD: engineering of systems for displaying optical information.

SUBSTANCE: liquid-crystalline screen is proposed, which has gaps for coolant between walls of liquid-crystalline cell and polarization changers. For pumping air through gaps, draining ventilator is used, because air during that expands in area of gap and cools down more. To decrease thermal effect on liquid-crystalline cell from external radiation, it is proposed to apply anti-reflective cover to surface of liquid-crystalline cell. Effect of infrared radiation on liquid-crystalline cells from heated polarization changers is weakened by creating a layer with high refraction coefficient, included in composition of anti-reflective cover, made of material with high conductivity.

EFFECT: possible use of liquid-crystalline screen under heavier thermal conditions, for example, in aviation, due to circulation of coolant and due to prevention of contact of liquid-crystalline cells with polarization changers, heating up during operation.

3 cl, 1 dwg

FIELD: engineering of systems for displaying optical information.

SUBSTANCE: liquid-crystalline screen is proposed, which has gaps for coolant between walls of liquid-crystalline cell and polarization changers. For pumping air through gaps, draining ventilator is used, because air during that expands in area of gap and cools down more. To decrease thermal effect on liquid-crystalline cell from external radiation, it is proposed to apply anti-reflective cover to surface of liquid-crystalline cell. Effect of infrared radiation on liquid-crystalline cells from heated polarization changers is weakened by creating a layer with high refraction coefficient, included in composition of anti-reflective cover, made of material with high conductivity.

EFFECT: possible use of liquid-crystalline screen under heavier thermal conditions, for example, in aviation, due to circulation of coolant and due to prevention of contact of liquid-crystalline cells with polarization changers, heating up during operation.

3 cl, 1 dwg

FIELD: optical signals processing.

SUBSTANCE: device has serially place, along one optical axis, optical coherent radiation source, collimator, ultrasound light modulator, first integrating lens, screen, second integrating lens and line of n photo-detectors, n subtraction blocks, n threshold blocks, adder with weight coefficient, support signal generator, delay line and voltage generator.

EFFECT: lower time for determining photo-detector number with maximum effect.

2 dwg

FIELD: electro-optics.

SUBSTANCE: magneto-optical element provided plane of polarization rotator based on Faraday-effect is made o f single single-axis crystal. Rotator has domains of both orientations in all its stable state without applied external magnetical field. Limits of domains for switching to any other stable state are disposed to move when external magnetic field is applied without forming additional domains.

EFFECT: reduced time for switching domains; reduced sizes of switching elements.

13 cl, 4 dwg

FIELD: fiber-optic and open digital and analog communication lines.

SUBSTANCE: proposed method involves concurrent transfer of two optical data signals over optical communication line, their reception and comparison, and noise suppression. Optical data signals are shaped across output of nonlinear optical element by supplying at least one optical beam to element input and varying input power or phase, or frequency of one optical beam supplied to input of nonlinear optical element, or by varying electric or acoustic field applied to this element. In this way optical change-over between two unidirectional distributed and coupled waves propagating through nonlinear optical element is ensured. Each of these waves at output of nonlinear optical element corresponds to optical data signal. These data signals are supplied to differential amplifier designed for subtracting electric signals and/or to correlator which separates coinciding part of amplitude of these signals as function of time. As an alternative, optical data signals are shaped across output of tunnel-coupled optical waveguides of which at least one functions as nonlinear optical element.

EFFECT: enhanced noise immunity of line, eliminated impact of photodetector noise onto data signal reception.

33 cl, 4 dwg

FIELD: optics.

SUBSTANCE: element has Bragg phase grid, which is formed in electric-optical material or in additional layer applied to it. Grid is provided with means for forming non-homogenous non-periodic outer electric field along direction of optical radiation movement, by means of which diffraction efficiency of grid is determined. Optical elements system has at least two Bragg phase grids, having different periods and placed serially along direction of movement of optical radiation. System of optical elements is controlled by effecting on grids with non-homogenous non-periodic outside electric field.

EFFECT: higher efficiency.

4 cl, 29 dwg

FIELD: measuring equipment.

SUBSTANCE: device has reflector, means for producing image and optical system for projecting image on display, as light source a board with light diodes is used, light flows of which are concentrated on an optical system. Protector is provided with sensor of outer light level and connected to common current adjuster.

EFFECT: broader range of use, higher precision, lower energy consumption.

2 cl, 16 dwg

FIELD: optical instrument engineering.

SUBSTANCE: electro-optic phase modulator has electro-optic chip, transparent electrodes and protective case. Transparent current-conductive electrodes are applied directly onto chip. Electro-optic chip provided with applied electrodes is flexibly fixed between protection glasses and is placed inside protective case.

EFFECT: simplified design; improved reliability.

FIELD: optics.

SUBSTANCE: magnetic device has variable magnetic field source which field is perpendicular to surface of magneto-optic material, and magnetic field source which field is oriented along gradient of magnetization of material. Magnetic field source which field is perpendicular to surface of magneto-optic material is made in form of transparent current-leading structures. One of conductors of the structure crosses center of light beam and the other one - along aperture of light beam in perpendicular to gradient of magnetization. Device permits to take control over location of optic vortexes within diffracted radiation and changes amount of information transmitted by light beam.

EFFECT: improved functional capabilities.

1 dwg

FIELD: optical engineering.

SUBSTANCE: multichannel optical commutator is made of two bunches of optical fibers, two collimators which have their focuses to place bunches' edges of, and light-guiding element mounted between collimators. As light-guiding element either mirrors or two acoustic-optical deflectors are used or their combination. Device allows to connect N users in series, which N user are connected to first bunch to S users which are connected to second bunch and visa versa and to conduct communication between users connected to one bunch.

EFFECT: units of fiber-optic assemblies and telecommunications can be made to provide speed of operation of channel switching within microsecond range and to provide number of switching channels up to 10000 at the same communication unit.

EFFECT: 21 cl, 12 dwg

FIELD: measurement technology.

SUBSTANCE: at least two stable or metastable ordering of liquid crystal are realized. Switching aid which causes the switching of liquid crystal material between switches has aid intended for optical illumination of the device. Device can provide the supply of linear polarized light for inducing torsion in liquid crystal. Alternatively ordering of liquid crystal can be switched by means of aid for supplying second energy, for example, electric field. In this case light serves to generate heat which helps to switching. One or both energy sources can be used locally for switching chosen areas or pixels. Energy levels on bistable substrate can be controlled by using oligomer adding (slippery surface).

EFFECT: improved efficiency of operation.

48 cl, 10 dwg

FIELD: measurement technology.

SUBSTANCE: at least two stable or metastable ordering of liquid crystal are realized. Switching aid which causes the switching of liquid crystal material between switches has aid intended for optical illumination of the device. Device can provide the supply of linear polarized light for inducing torsion in liquid crystal. Alternatively ordering of liquid crystal can be switched by means of aid for supplying second energy, for example, electric field. In this case light serves to generate heat which helps to switching. One or both energy sources can be used locally for switching chosen areas or pixels. Energy levels on bistable substrate can be controlled by using oligomer adding (slippery surface).

EFFECT: improved efficiency of operation.

48 cl, 10 dwg

Up!