Fiber optic receiver gradient of the sound pressure
(57) Abstract:The invention relates to the field of hydro-acoustics and can be used in laboratory and field conditions to measure sound waves in the liquid. The essence of the invention lies in the fact that single-beam fiber Zehnder interferometer is a Mach, having as two sensor fiber coil located at a certain distance from each other, complemented by a multibeam dvuhgolosiem the interferometer having three associated optical fiber coil. With two coils of both interferometers are common. Junction interferometers is carried out through the use of different wavelengths generated by two lasers. Single-beam interferometer has a harmonic output curve and multibeam - acute fringes output curve. This allows for homodyne conversion to use multibeam interferometer for receiving weak acoustic signals, and one for receiving stronger acoustic signals. The receiver has an electronic circuit to automatically select the operation mode depending on the level of the acoustic signal. 1 C.p. f-crystals, 3 ill. The invention from the parameters of the sound waves in the liquid.Known fiber-optic receivers (GPS) gradient of the sound pressure [1, 2] used both in laboratory and in situ conditions. Any of known UXO may be adopted for the prototype.Known UXO, for example,  contains the laser and the photodetector, optically coordinated through two fiber coils located at a certain distance from each other, in one-Zehnder interferometer is a Mach, and a high-pass filter, amplifier and multichannel recorder, and the output of the photodetector through the filter high-frequency connected to the input of an amplifier output connected to a multi-channel recorder.A disadvantage of the known devices [1 and 2] is not sufficiently high sensitivity GPS mode homodyne conversion, limited by the limiting slope of the sine wave, which changes the output curve is known gradient receiver 
The technical result obtained by the invention is to increase the sensitivity of fiber-optic interferometric receiver gradient of the sound pressure by increasing the slope of the output curve of the interferometer mode homodyne conversion.Dunn is the laser and the photodetector, optical coordinated through two fiber coils located at a certain distance from each other, in one-Zehnder interferometer is a Mach, and a high-pass filter, amplifier and multichannel recorder, and the output of the photodetector through a high pass filter connected to the input of an amplifier output connected to a multi-channel logger further comprises a third fiber coil, protected from sound pressure, a second laser, the second photodetector, the second high pass filter and a second amplifier when the lasers are made at different wavelengths, fibers of the first and second coils are made of material transparent to both the wavelength of the laser, and the third fiber coil of material transparent to the wavelength of the second laser, but not permeable to the wavelength of the first laser, the second laser and a second photodetector optically aligned with the first, second, and third fiber coils in the multibeam dvukhkontsevoi interferometer, while before the first photodetector has an interference filter at the wavelength of the first laser and the second photodetector has an interference filter at the wavelength of the second laser, and the output whoredom to multi-channel logger.The first and second fiber coil is made of quartz glass fibers, and a third of the polymeric fiber, the first laser is performed on a wavelength A, and the second wavelength A.The GP may further comprise two integrator, two Comparators, two blocks of reference voltages and two electronic key, the first integrator is connected by its input to the output of the first amplifier, and the output to the first input of the first comparator, a second input connected to the first block of the reference voltage, and the output from the controlled input of the first electronic switch, a second integrator connected by its input to the output of the second amplifier, and the output to the first input of the second comparator, a second input connected with the second block of the reference voltage, and the output from the controlled input of the second electronic key, moreover, the outputs of the first and second amplifiers connected to the multichannel inputs of the Registrar respectively through the first and second electronic switches.The TPO further comprises a scaling device installed at the outlet of the first or second electronic keys.The GP may further comprise two phase-shifting device, one of which ustanavlivaetsya drawings.In Fig. 1 shows the optical scheme of the GP; Fig. 2 electronic circuit GP; Fig. 3 chart explaining the operation of the GPS.Fiber optic receiver gradient of the sound pressure (Fig. 1) includes a laser 1 operating at a wavelength of1laser 2 operating at a wavelength of2and three fiber reels 3, 4 and 5 (coil 5 is conventionally shown in the form of one turn of the spiral). There are also two of the photodetector 6 and 7, before whom there is interference filters 8 and 9, one 8 length2and the other 9 on the length of the1.The laser 1 and the photodetector 7 is optically aligned with the fiber coils 3 and 4 in single-beam Zehnder interferometer is a Mach. Coordination occurs with the introduction of the optical device 10, the fiber couplers 11, 12 and output optical device 13.Laser 2 and the photodetector 6 is optically aligned in the multibeam dvukhkontsevoi the interferometer through the fiber coil 3, 4, 5.Coordination occurs through the introduction of optical device 14, the fiber couplers 11, 12 and the optical output device 15.Ways to coordinate the optical elements in a single beam in the multi-beam fiber interferometers presents the different coils 3 and 4 are made of material, transmissive length1and2waves of both lasers 1 and 2, and the fiber coil 5 is made of a material transparent to the wavelength of the2laser 2, but not permeable to the wavelength of the laser 1. In addition, before the photodetector 7 install the interference filter 9 per wavelength1and before photodetector 6 - filter 8 per wavelength2.In the particular case of fiber coils 3 and 4 are made of quartz glass fibers and the fiber coil 5 of the polymeric fiber, the laser 2 use the ruby laser with a wavelength of A, and as the laser 1 helium-neon laser with a wavelength of A. Optical loss quartz radiation at first and second wavelengths respectively (5) 6 and 10 dB/km, and polymer fibers 60 and 7 dB/km i.e quartz fiber transmits selected wavelengths is almost the same, and polymer - skips only one wavelength.The optical scheme of the TPO also includes two phase-shifting devices 16 and 17. The phase-shifting unit 16 is installed in the fiber coil 4, and the phase-shifting device 17 in the fiber coil 5.The sensitive element of the GP are fiber coils 3 and 4, located on rasoun outside of the study area and to be made in the form of resveratol fiber length (i.e., straight cut fibers).An electronic circuit GP (Fig. 2) includes a filter 18 and 19 high frequency amplifiers 20 and 21, the integrators 22 and 23, the Comparators 24 and 25, the Comparators 26 and 27, the electronic switches 28 and 29, the scaling unit 30 and multichannel recorder 31.Connection diagram shown in the drawing.Fiber optic receiver gradient of the sound pressure is as follows.Install the sensing element of the TPO in the test environment so that the fiber coil 3 and 4 were located one behind the other with respect to the sound wave 32 (Fig. 1).Suppose that the input signal GP has the appearance shown in Fig. 3, under item 33 (here under the positions 34 and 35 presents the output curves, respectively, single-beam and multibeam interferometers).If the pre-use phase-shifting devices 16 and 17, the initial phase difference set in the point a (the point of greatest curvature and linearity of the output curves 34 and 35), the receiver can be considered ready for use.Assume that you start working less sensitive single-beam interferometer.Sound wave 32 (Fig. 1) causes the appearance on pricescope signal amplitude. The interference filter 9 passes useful optical signal on the photodetector 7, the output of which is allocated signal 36 (Fig. 3). The variable component proportional to the gradient of the sound pressure of an acoustic wave 32 (Fig. 1), is amplified by the amplifier 30 and is recorded on a multichannel recorder 31 (Fig. 2).At the same Registrar you can register and the output signal is more sensitive multibeam interferometer. And subsequent analysis allows you to choose one or the other of the recorded output signals, depending on the magnitude of the input signal.The selection of the mode of EO can be done automatically.For this purpose, the integrator 22 directs the integrated output signal to a comparator 24 for comparing the output signal level with a reference voltage unit 26 reference voltages characterizing the limiting sensitivity of the single-beam interferometer and the maximum linear range of the multibeam interferometer. If the output signal of the single-beam interferometer more support, then the output signal is passed electronic key 28 on a multichannel recorder 31, if less, the signal is delayed and informaregulations interferometer with the photodetector 7 through the filter 19 to the high frequency and the amplifier 20 is fed to the integrator 22, after which, in the comparator 25 compares the value of the other reference voltage (block 27 reference voltages). The value of the second reference voltage is selected as the linearity of the plot output curve 35 multibeam interferometer for a given signal level. If the integrated value of the output signal of the multibeam interferometer does not exceed the reference, the signal passes through an electronic key 29 on a multichannel recorder 31. If exceeded, the signal is delayed electronic key 25 and begins to work one-beam interferometer.The scaling unit 30 allows you to record the output signals of the various interferometers in the same scale.Thus, the GP can increase the sensitivity of the device without reducing its operating range.Sources of information:
1. G. B. Mills, S. L. Garrett, E. F. Carome. Fiber optic gradient Hydrophone "Proc. Soc. Photo-Opt. Instrum. Eng.", 1984, Fiber Opt. and Laser Sinsors II, Proc. Conf. Arlengton, Va, Tay 1-2, 1984, 98-103. (R. D. MIT, 1985, N 10.32.420).2. U.S. patent N 4799752, CL 350-9615 (C 02 B 6/26), 1989. 1. Fiber optic receiver gradient of the sound pressure, containing a laser and a photodetector, optically coordinated through two fiber coils, RAS well as a high-pass filter, the amplifier and multichannel recorder, and the output of the photodetector through a high pass filter connected to the input of the amplifier, is connected by the output to multi-channel recorder, characterized in that it further contains a third fiber coil, protected from sound pressure, a second laser, the second photodetector, the second high pass filter and a second amplifier, and two phase-shifting device, one of which is installed in the first or second fiber coils, and the other in the third fiber coil, while the lasers are made at different wavelengths, fibers of the first and second coils are made of material transparent to the radiation of both lasers, and the third fiber coil of material transparent to radiation of the second laser, the second laser and a second photodetector optically aligned with the first, second, and third fiber coils with the formation of multibeam controllable two-annular interferometer, while before the first photodetector has an interference filter at the wavelength of the first laser and the second photodetector has an interference filter at the wavelength of the second laser, and the output of the second photodetector through the second filter high cha is 2. The receiver under item 1, characterized in that the first and second fiber coil is made of quartz glass fibers, and a third of the polymeric fiber, the first laser is performed on a wavelength and the second wavelength N
FIELD: the invention refers to the mode of manufacturing lens in the shape of peaks on the end-faces of single-mode and multi-mode optical fibers.
SUBSTANCE: the manufacturing mode is in plotting drops of polymerized substance on the end-face plane of the fiber, radiation of the plotted drop with a source of light for realization light photo polymerization. At that before exposure they choose one or several desired modes subjecting the optical fiber to mechanical strains, at the stages of plotting the drop and radiation they execute control and management of the form and the sizes of the peak, before the radiation stage they hold out the mixture at the given temperature for achieving viscosity of the mixture which allows to get the needed height of the drop, regulate duration of exposure and/or intensity of the light for regulating the end radius of the curvature of the peak.
EFFECT: provides possibility to get peaks of different heights and different radiuses on the end-face planes of the optical fibers and also provides possibility to control the indicated parameters of the peaks in time of their manufacturing.
26 cl, 13 dwg
FIELD: electrical engineering .
SUBSTANCE: device for introduction of laser emission in fibre, which contains optical single-mode or multimode fibres equipped with microlenses that are shaped of transparent materials, differs because microlenses are made of optical glass, refractive exponent of which is higher than the refractive exponent of light conducting thread of fibre, in the shape of sphere that embraces light conducting thread at the end of fibre, and the end surface of fibre is made in the form of polished cylindrical surface, besides, axis of cylindrical surface intersects with fibre axis and is perpendicular to fibre axis.
EFFECT: increases coefficient of emission introduction and reduces dependency of introduction coefficient on misalignment.
5 cl, 5 dwg
FIELD: physics; optics.
SUBSTANCE: invention relates to devices for splitting optical fibres, specifically to manual portable instruments. The mechanism for breaking optical fibres contains apparatus for breaking fibres and one or more clamping elements which can clamp an optical fibre at one end, which should be cut off, and apply a pulling force so as to stretch the fibre when breaking it. The mechanism is designed such that, the clamping element(s) can also push the broken part of the fibre using devices which enable the clamping element(s) to continue applying a pulling force to the cut off part of the fibre after breaking. The clamping element or each clamping element releases the cut off part when moving the cut off part of the fibre.
EFFECT: high quality joining and reliability of fibres.
11 cl, 15 dwg
SUBSTANCE: fibro-optical connector comprises first and second half-couplings to receive first and second sections of optical fiber. First and second pairs of step-down optical multilayer transformers are arranged on end faces of said sections. Air gap is arranged between outer layers of said first and second pairs of said transformers. Layers of first and second pairs of aforesaid transformers are made from materials with differing indices of reflection and are counted from outer layers of aforesaid transformers in direction of the end faces of connected sections of optical fiber. Thickness of every layer makes one fourth of average signal wave λ0 transmitted over optical fiber, while the number of layers is selected subject to conditions covered by invention claim.
EFFECT: reduced power loss, expanded performances.
4 cl, 9 dwg
SUBSTANCE: fibre-optic connector has first and second half couplings for sealing first and second sections of optical fibre on whose butt ends there are first and second pairs of step-up and step-down optical multi-layer transformers. There is an air gap between the outer layers of the first and second pairs of optical multi-layer transformers. Layers of the first and second pairs of optical multi-layer transformers are made from materials with different refraction indices and are measured from outer layers of step-down transformers of the first and second pairs of optical multi-layer transformers adjacent to the air gap towards the butt ends joined to optical fibre sections. Thickness of each layer is equal to a quarter of the medium wave Xo of the signal transmitted over the optical fibre and the number of layers is selected based on conditions given in the formula of invention.
EFFECT: lower level of power loss arising due to insufficiently close contact or welded joint at the position of the joint and wider range of apparatus for this purpose.
4 cl, 7 dwg
FIELD: oil and gas extraction.
SUBSTANCE: fibre-optic rotating connector with a symmetrical structure has a housing in which there is a first and a second fibre-optic waveguide. The first fibre-optic waveguide is mounted in the first optical terminal piece which is fixed in bearing housings with possibility of rotation. There is a spacer ring between the bearings. The second fibre-optic waveguide is mounted similarly. The optical terminal pieces are pressed to each other by springs and coupling nuts. Displacement between optical axes of the fibre-optic waveguides is the limiting value of the radial beat of the inner ring of the roller bearing is defined by the expression: where α is the radius of the fibre-optic waveguide, Pi is the power at the end of the transmitting waveguide, Pp is the power at the end of the receiving waveguide, z is the distance between ends of interfaced waveguides, NA is the numerical aperture of the fibre-optic waveguide, r=α+z·tgα is the radiation field distribution radius in the plane of the end of the receiving waveguide, sinα=NA.
EFFECT: simple design, reliability, low optical loss.
4 cl, 1 dwg
SUBSTANCE: optical cable connector has an invar housing in form of a bushing on whose two sides of which there are two nodes through which cables pass. The node which can rotate consists of a shaft with a stepped hole along the axis, bearings and a spacer bushing. The rigidly mounted node consists of a bushing superimposed with a ferrule. The ferrule has a lateral recess which is filled with gel and is closed with a casing. Cleared ends of the cables are placed in the lateral recess.
EFFECT: more reliable operation and miniaturisation.
3 cl, 4 dwg
SUBSTANCE: apparatus has two collimating units which can turn relative each other around an axis of rotation, and one optical element which compensates for rotation. A first power splitter receives input signals and splits said signals into at least two signals for transmission over at least two optical channels through the collimating units and the optical element compensating for rotation. After passing through the second collimating unit, the signals are combined into one signal in a second power splitter. A version of the apparatus has an optical attenuator which is connected to one component from the first collimating unit, the second collimating unit and the optical element compensating for rotation, or a gear which rotates the optical attenuator. In one of the versions, the attenuator is controlled by a controller.
EFFECT: minimisation of change in attenuation in a rotary joint during rotation, as well as provision for transmission of analogue optical signals which carry information encoded in the amplitude or level of the signal.
17 cl, 9 dwg