Microresonator fiber optic physical quantities
(57) Abstract:Microresonator fiber optic physical quantities can be used to measure temperature, pressure, acceleration. The Converter contains a fiber-optic laser, one end of the optical fiber is coupled to the collimator forming a parallel beam of light to the reflecting surface of the microcavity. The second end of the fiber, which output is connected to the spectrum analyzer through the photodetector. The reflective surface of the microcavity is under some given angle to the axis of the collimated beam of light. Self-oscillating mode in the system of fiber-optic laser - microresonator is due to modulation of the amplitude of the reflection coefficient of the optical resonator fiber laser or q-switching two-mirror optical resonator due to photoinduced angular deviations of one of the mirrors, which serves as the reflecting surface of the microcavity. Stable measurement results. 2 C.p. f-crystals, 3 ill. The invention relates to fiber-optic transducers of physical quantities (temperature, d is known to work on the creation of a new class of fiber-optic sensors (WATER) physical quantities based on micromechanical resonator (Mr) and optical radiation, interacting with the microcavity MP. In the literature reported the development of various schemes for optical excitation of vibrations Mr and their practical implementation. In all cases, the intensity modulation of optical radiation occurs at the resonance frequency of the MRI.When it absorbs MP optical radiation of its illuminated side is experiencing thermal expansion, resulting in Mr occurs bending moment varying in phase with the modulated optical radiation, which leads to mechanical vibrations at the resonance frequency of the MRI.External influences (temperature, pressure, acceleration, etc.) is converted into the internal stress MRI, which leads to change of its own resonant frequency determined by the dimensions of the Mr and its physical properties.Due to small amplitude oscillations Mr ( 0.1 ám) in WATER physical quantities used interferometric method for obtaining information about the resonance frequency of the Mr using the Fabry-Perot interferometer, a resonator which is formed of a reflective surface Mr and semi-transparent mirror or the end face of the light guide, sopryazhennymi with a reflective surface Mr.However microresonator WATER physical quantities, based on photometric Mr excitation and optical detection of oscillations, have the following drawbacks: the position of the working point And the Fabry-Perot interferometer unstable and shift depends both from the drift of the main characteristics of the Mr, and the instability of the radiation source and the parameters of the Fabry-Perot interferometer.In other words, on the effective functioning of the WATERS of the physical quantities simultaneously affect the instability characteristics of the channel of the Mr excitation and channel interferometric information retrieval that requires special measures to stabilize the position of the working point A.Closest to the proposed technical solution to the technical essence and the achieved result is a fiber optic sensor (WATER) physical quantities (application WO 89/00677, CL G 01 D 5/26, 26.01.89) containing a laser radiation source, the optical fiber, the splitter, collimator, microresonator with the reflecting surface, the photodetector and high stability requirements power source (the pump current of the laser diode) and careful control of the operating point of the Fabry-Perot interferometer due to changes in the small limits of optical radiation power, falling for Mr; additional loss of optical power caused by the presence of the necessary discrete elements forming an additional feedback channel in the electronic circuit; stringent requirements on the stability characteristics of the resonator Fabry-Perot, and characteristics of Mr in because of the limited possibilities of their correction in the present electronic circuit; limited adjustment of the working point of the Fabry-Perot interferometer by changing the wavelength of the optical radiation of the laser diode when implementing complex electronic circuits reverse the positive connection.The problem solved by this invention is the development of a microresonator optical fiber transducer of physical quantities on the basis of fiber-optic laser and the q-switching two-mirror optical resonator due to photoinduced angular deviations of one of the mirrors, which serves as the MP.At one end of the single-mode optical fiber, the optical fiber laser is associated with a collimator that forms a parallel light beam on the reflective surface Mr, the normal to which makes an angle with the axis of the incident beam, stvie effect of photoinduced deformation to the modulation of the deflection angle of the reflected beam (t), i.e., the modulation of optical power.As a collimator uses a gradient rod lens (GSL) in a quarter of a period, forming a Gaussian beams.Regardless of the topology and design of the Mr under certain conditions in the device is self-oscillating mode with frequency F, which practically coincide with the resonant frequency f F.These conditions are as follows: in the initial state, the deflection angle =andis in the interval1and2limits (1,2) depend on the characteristics of Mr and optical fiber laser; the resonant frequency of the Mr is close to the frequency of the relaxation oscillations of fiber-optic laser fRel.or its harmonics, i.e., f n fRel.where n = 1, 2, 3,..., n. Note that fRel.is determined by the relative pumping m = Pn/PN. p.where PN. p.- the threshold level of the laser pump; average radiation power exceeds a certain threshold level is dependent on characteristics of the Mr and optical fiber laser.As a result of the system Mr-fiber-optic laser self-oscillations at the resonant frequency of the Mr no nThe essence of the proposed technical solution is the development of a microresonator optical fiber transducer of physical quantities, in which the excitation of self-oscillations at the resonant frequency of the Mr uses a fiber-optic laser without introducing additional optical fiber devices. Thus the existence of the self-oscillatory mode in the system Mr - fiber-optic laser is carried out by modulation of the amplitude of the reflection coefficient R of the optical cavity fiber laser, resulting from photoinduced angular deviations Mr, normal to the reflective surface which is oriented at an angleandto the optical axis of the collimated beam of light.Fiber optic laser is a segment of single-mode type optical fiber of length l, the pumping can be performed in various ways, for example through the segment buffer of non-activated fiber, is perfectly consistent with carbon fiber.The unique properties of the fiber-optic laser to achieve the effective optical approval of Mr with fiber-optic laser, and najcescih materials such as Si, SiO2, CaAs allow you to implement Mr patterns with predetermined acoustic and optical characteristics and topology (for example, in the form of micromembrane, micromastia, microconsole and so on), allowing the system Mr - fiber-optic laser self-oscillations, resonance frequency which depends on the impact of relevant external factors: temperature, pressure, acceleration, etc.From the above it follows that the new properties system Mr - fiber-optic laser give reason to consider this system as the basis for developing principles of frequency converters of physical quantities of different designs.Note that with this method of excitation of self-oscillations for the effective interaction of fiber-optic laser with Mr it is necessary to consider the relationship of parameters of optical fiber system, the geometric dimensions of the MRI and the relative instability of the resonant frequency of the oscillator.Consider this question for a microresonator converters with basic topology: micromatic on the membrane and micromatic for measuring pressure and temperature, respectively.Ratios are the - the thickness of the bridge; d is the thickness of the membrane; r is the radius of the membrane; and E is the Poisson's ratio and young's modulus for the material of the Mr, respectively; H is the distance between GSL and Mr.From (1) it follows that with increasing L Kpdramatically, however, the resonant frequency of the Mr f0hs/L2this significantly decreases. Given that, for example, when f0= 10 kHz frequency measurement signal with a relative error f/f0=10-4requires minimum time for signalmin= 1, and if f/f0=10-5youmin= 10, which may be unacceptable from the point of view of providing the necessary speed sensor should be taken that the resonant frequency of the applied Mr must be equal to f059 kHz.So, when f0= 50 kHz will get the following optimal from a performance perspective, and apply the ratio signal/noise dimensions of a microresonator structure: L = 900-1400 μm, hs=5-7 µm, r =900-1400 mm. While the conversion factor for a microresonator pressure sensor with dimensions L = 1200 µm, hs= 6 ám, d =30 μm, H = 30 μm get Kp= 400% ATM-1.As for the temperature sensor, the coefficient of conversion; hsthe film thickness (for example, Nickel), applied to the reflecting surface of the bridge.The resonant frequency of micromastia with the metal film density of Psiis determined by the expression
< / BR>Similarly, the pressure sensor conversion temperature Ktdescribed by expression (2), with increasing L increases, and the resonance frequency according to (3) with significant falls. To achieve the specified performance and apply the ratio signal/noise dimensions microresonator structures were selected as follows: 1400 x 300 x 6 mm. The resonant frequency of the main fashion was f56,3 kHz at T20oC. In the temperature range of 10-70oC system was still in the mode of stable self-oscillations ( - coefficient).For the chosen parameters of a microresonator structure at the instability frequency oscillator f/f = 210-4have Kt=-0,08% K-1. According to the results of experimental studies of the temperature measurement error at room temperature is
< / BR>In Fig. 1 presents a diagram of a microresonator optical fiber transducer of physical quantities, allowing you to control the resonant hour fiber-optic laser and collimator. Here 1 - fiber-optic laser (OX), 2 - MP, 3 - collimator, 4 - isotropic single-mode fiber, 5 - semi-transparent mirror M1, which serves as the interface of the fiber - air with a reflectivity of R1=3,2%, 6 - sensor, 7 - spectrum analyzer, 8 - semiconductor pump laser at a wavelength of = 0.98 μm, 9 - external influence (pressure P, temperature T, and so on).The device operates as follows. As a result of exposure measured physical quantities regardless of the type and parameters of the Mr system is installed self-oscillating mode with frequency F, which coincides with the resonant frequency of the i-th fashion lebani Mr: fi=F, where i = 1, 2,..., m. When this self-oscillating mode in the system Mr-fiber-optic laser is carried out by modulation of the amplitude of the reflection coefficient R of the optical resonator fiber laser due to photoinduced corner otklonennyj mirror, which is Mr.In Fig. 2(a) shows the topology Mr "micromatic on the membrane" microresonator optical fiber pressure transducer. Here the position of the LASS="ptx2">In Fig. 2(a) depicts the 3 - collimator 10 - micromatic thickness hs11 - the membrane thickness d, 12 - a distance H between GSL and Mr, R is the radius of the membrane, L is the length of micromastia.The principle of fiber-optic pressure transducer with Mr, made in the form of macromastia on the membrane and oriented at an angleandto the optical axis of the collimator 3, based on the fact that the pressure P causes deformation of the membrane, which is micromatic 10. Due to this deformation micromastia arise tensile (or compressive) stress, leading to change of the resonance frequency of micromastia.High conversion factor Kpconfirmed by the experimental data of the dependence of the frequency of self-oscillation of F on pressure for Mr with the following parameters: L = 1650 μm, hs= 6 ám, d = 130 ám, r = 1900 μm, H = 200 ám.Note that in this case micromatic and membrane were made of heterogeneous materials: micromatic from silicon membrane is made of glass. The experimental data of Kp= 20% ATM-1that agrees satisfactorily with the evaluation of Kpobtained by the formula (1) and equal to Kp= 16% ATM-1.The principle of fiber-opt case if Mr use micromatic on the membrane, made of a homogeneous material, for example of monocrystalline silicon anisotropic etching method.For a given value of the pressure fluctuation frequency of the oscillator was (F/F)FL= 2 10-4that corresponds to a standard error of measurement pressure
< / BR>Thus, on the basis of experimental data it can be argued that the measurement error of the pressure in the vicinity of P 1 ATM is P = 110-3the ATM.In Fig. 2(b) shows the topology Mr "micromatic" microresonator optical fiber transducer temperature. Here position 1 is a top view of Mr in the form of micromastia, item II - side view of the Mr section a-a of the same microcavity. In Fig. 2(b) shows: 3 - collimator 10 - micromatic thickness hs, 12 - H distance between GSL and Mr.The principle of operation of a fiber-optical temperature transducer with Mr, made in the shape of micromastia and oriented at an angleandto the optical axis of the collimator 3, based on the fact that the temperature T is the deformation of micromastia, resulting in micromastia arise tensile (or compressive) esperimental obtained the dependence of the frequency of self-oscillations of pressure F(P) and the dependence of the frequency of self-oscillations of temperature F(T) (a and b, respectively). The experimental dependence of the frequency of self-oscillations on the temperature of micromastia T was measured by using a Peltier element in the temperature range of 10-70oC. Microresonator film of Ni had dimensions 1400 x 300 x 6 mm. The resonant frequency of the main fashion at room temperature was equal to F 56 kHz. When the temperature variations in this range of values, the system was still in the mode of stable self-oscillations. The function F(T) is almost linear with temperature coefficient
< / BR>At a constant temperature Mr of short-term frequency instability of the oscillator was (F/F)FL= 210-4. Therefore, the accuracy of this transducer temperature equal
< / BR>what percentage corresponds to 0.3% in the measured temperature range.Note that the experimental value of the temperature coefficient agrees satisfactorily with the calculated calculated according to the formula (2). In addition, it should be emphasized that according to (2) Ktsignificantly depends on the presence of residual internal strain of micromastia, given that =0+twhere0- the term describing the source of the internal deformation of the microresonator article is microresonators patterns, change0allows you to control the conversion coefficient Kt, i.e., the effect of residual deformations0can be crucial when determining TOt.Thus, by spraying micromatic corresponding material of the required thickness can be formed of a temperature-sensitive microresonator structure in accordance with a specified range of measured temperatures. 1. Microresonator fiber optic physical quantities, comprising a laser source of the optical radiation from the optical fiber, microresonator, the photodetector and the spectrum analyzer, with one end face of the light guide is associated with a collimator interposed between this end and the microcavity, and the second end of the fiber is an output and is connected to the spectrum analyzer through the photodetector, wherein the laser source of the optical radiation is made in the form of fiber-optic laser, thus reflecting surface forms a microcavity with an output end of the optical fiber, the two-mirror optical resonator fiber laser, and the reflecting surface of the microcavity in the initial position is oriented to the protected area, the optical transducer of physical quantities under item 1, wherein microresonator made in the form of macromastia on the membrane.3. Microresonator fiber optic physical quantities under item 1, characterized in that microresonator made in the form of micromastia.
FIELD: instrument engineering.
SUBSTANCE: converter can be used for measuring parameters of acoustic fields in gases and liquids. Fiber-optic converter has optical radiation source exciting circuit, optical radiation source, optical coupler, auxiliary optical radiation, fiber-optic light guide made in form of cylindrical two-channel coaxial tied structure, which has rod single-mode waveguide and tubular single-mode waveguide. Device also has optical radiation divider, which divides optical radiation from rod waveguide and tubular waveguide, optical radiation receiver for receiving optical radiation from output of rod waveguide , additional optical radiation receiver which receives optical radiation from output of tubular waveguide, and analog signal processing unit.
EFFECT: improved precision of fiber-optic converter.
FIELD: measurement technology; electric-power industry; geological prospecting; aircraft industry.
SUBSTANCE: device can be used for inspecting deformations in big structures, for measuring temperature modes of transformers and temperature distributions along wells and for checking structural deformations in flying vehicles. Device has comparator, pulse former and pulse sampling unit for selecting optical pulses after they were reflected from reference point. As reference points the optical connectors are used mounted among sections of fiber-optic cable, which is used as measuring transformer. Selected pulses run auto-oscillating mode through positive feedback circuit. Oscillation repetition period defines delay in propagation of optical signal to selected reference point. Changes in temperature and influence of mechanical stresses resulting to deformation of optical fiber change refraction factor of material of optical fiber core. Due to change in refraction factor the delay of optical signal changes. Value of temperature or value of deformation acting on any section of measuring transformer are determined by change in delay of optical signals from any reference point.
EFFECT: simplified design; improved precision; widened dynamic range of operation.
FIELD: measuring technique.
SUBSTANCE: fiber-optic deformation sensor comprises generator of sinusoidal signals that modulates the intensity of laser emitter and spectrum analyzer that is used for determining the resonance frequencies of the signal of back scattering from the measuring converter. The values of the resonance frequencies are related to the mechanical deformation of different zones of the structure that is provided with the measuring converter.
EFFECT: reduced measurement time.
FIELD: oil-gas industry, possible use for diagnostics of extensive objects used during operation of wells or during transportation of product to collection stations and further, etc.
SUBSTANCE: method for monitoring status of extensive objects includes equipping extensive object with sensitive optical fiber, producing a series of coherent optical impulses with length T with spectrum width about 1/T and temporal interval between impulses equal to T1, organization of reflection-metric channel and feeding aforementioned impulses into sensitive optical fiber with length L, registration of amplitude of reverse dissipation signals, comparative analysis of aforementioned reverse dissipation signals in serial reflectograms and selecting local changes in them, pointing at presence of influence on extensive object, while coordinate of position of influence resulting from presence of selected local changes along the length of sensitive optical fiber is determined by position of changes on reflectogram, while a condition is maintained, in accordance to which length L of sensitive optical fiber is such, that temporal interval T1 between impulses exceeds value 2L/V, where: V-speed of light in sensitive optical fiber, while registration of amplitude of reverse dissipation signal is performed by means of photo-receiver with temporal resolution not worse than duration of impulse T. The method is realized by means of an appropriate device.
EFFECT: decreased requirements to coherence of impulse source of optical radiation used during diagnostics (width of optical impulse spectrum may be equal to about 1/T); increased number of measuring channels and working length of sensitive optical fiber.
2 cl, 3 dwg
FIELD: laser technology; measuring technique.
SUBSTANCE: device and method can be used for fiber-optic measurement of spatial distribution of temperature/deformation of elongated objects, namely, it can be used in oil industry, power engineering, automotive industry for monitoring of deformations in structures of bridges, supports and buildings. System has radiation source - laser - optically connected with optical fiber (with diameter of 150-600 mcm and diameter of core of 12-20 mcm) composed of point detectors on base of Bragg fiber arrays, reflecting light at different resonant wavelengths; fiber beam-splitting unit; spectrum analyzer in for of photoreceiver. Detectors with different reflection factors and/or with different width and shape of spectrum reflection alternate in optical fiber to follow preset order, including selection into groups. Detectors are recorded in thick optical fiber by laser at wavelength of 240-270 nm and at power of 0,5 W and higher. They also van be recorded through protecting polymer envelope disposed onto light guide by means of laser radiation at wavelengths of 270-450 nm and at power of 1 W and higher. Uniformity and stability of recorded Bragg array is improved.
EFFECT: improved reliability; reduced cost; higher speed of operation; increased sensitivity of array to environment influence.
4 cl, 2 dwg
FIELD: invention refers to measuring technique.
SUBSTANCE: sensor of measuring of deformation has at least one sensor element which provides changing of quantity of passing light at changing curvature of light guide. Sensor element is confined in body fulfilled with possibility of impacting on sensor element from one side with aid of pusher in shape of at least from one side of elastic wall of body or with aid of pusher passing through wall of body and having possibility to impact on sensor element and from other side with aid of support in shape of immovable wall of body. Pusher ensures perception of deformation of medium and/or deformation of surface, and body ensures possibility of switching of at least one light guide for supply light from source of light to sensor element and discharge of output light from sensor element.
EFFECT: invention is assigned for accommodation of optical sensor for measuring of deformation of elements of building constructions including reinforced concrete.
SUBSTANCE: fibre-optic temperature sensor has a capillary inside of which there is optical fibre and a light-reflecting element which is placed at a distance from the butt end of the optical fibre. According to the first version, the sensor has a housing with a through hole and two blind holes coaxial with the through hole. In one of the blind openings there is a thread for a screw whose end is inserted into the through hole and has a light-reflecting butt end. In the opposite threaded blind hole there is an iron ring rigidly attached to the housing with a capillary inside which is also inside the through hole. According to the second version, the fibre-optic temperature sensor has a housing with a through hole and two blind holes coaxial with it. In each of the blind holes there is an iron ring with a capillary inside, where the capillary is also inside the through hole. One of the iron rings is rigidly attached to the housing. According to the third version, a fibre-optic deformation sensor has capillary inside of which there is an optical fibre and a light-reflecting element which is fitted at a distance from the butt end of the optical fibre. The sensor has a dumbbell shaped housing with cylindrical outer surfaces. On the surfaces of the ends of the housing there are threads, with a right-handed thread on one end and a left-handed on the other.
EFFECT: increased measurement accuracy, protection of the sensor from external mechanical effects, possibility of attaching the housing of the sensor to measurement objects, shorter time for transfer of temperature from objects to sensor elements and transfer of deformation of the material of objects to active elements of the sensor.
17 cl, 5 dwg
SUBSTANCE: fibre-optic position sensor has a magnetic or electromagnetic element, a broad-band light source, optical fibre, at least two sensors in form of a fibre-optic Bragg grating made from optical fibre, at least one segment of magnetostrictive material, a rod made from magnetic field impermeable material. At least one of the two sensors is attached to the segment of the magnetostrictive material, where at least one of the segments of magnetostrictive material is attached to the rod. The magnetic or electromagnetic element and the rod are superposed in such a way that they experience displacement only along the axis of the rod. Said displacement causes changes in the dimensions of the segment of magnetostrictive, which leads to changes in the length of waves reflected by the sensors in form of a fibre-optic Bragg grating.
EFFECT: ensuring safety when using the sensor in explosion hazard zones owing to absence of electrical signals in the immediate proximity of the measurement point.
16 cl, 11 dwg
SUBSTANCE: optical reflectometre generates a probing pulse which falls on a first examined Bragg grating through a circulator. Part of the probing pulse is reflected from the grating and falls on reference gratings whose reflection spectra lie equidistant from the spectrum of the examined Bragg grating. Two reflected signals are generated, having power which is determined by the spectral interval between the spectrum of examined grating and the spectrum of the corresponding reference grating. Reflected signals are returned to the reflectometre and are displayed on a reflectogram in form of two peaks whose amplitude is proportional to the power of these signals. The spectrum of the examined grating shifts in case of an external physical effect. One of the peaks increases while the other falls. The difference between the amplitude of these peaks is the picked up signal. In order to pick up signals of the next groups of examined fibre Bragg gratings, the reference Bragg gratings are rearranged so that the initial resonance wavelengths of the examined fibre Bragg gratings are exactly between the resonance wavelengths of reference Bragg gratings.
EFFECT: wider measurement range and high resistance to amplitude noise.
SUBSTANCE: reflectometer has a pulse modulator and a pulsed radiation source connected to each other and a means of facilitating bidirectional transmission of radiation. The means of facilitating bidirectional transmission of radiation is connected to the pulsed radiation source, a sensitive fibre and through a photodetector to a control and processing unit, which is connected to the input of the pulse modulator. The connection between the means of facilitating bidirectional transmission of radiation and the pulsed radiation source is in form of two optical paths formed by two optical splitters. One of the splitters is connected to the output of the pulsed radiation source and the other to the means of facilitating bidirectional transmission of radiation. One of the optical paths has a delay line and the other has a phase modulator connected to the control and processing unit.
EFFECT: improved invention.
9 cl, 2 dwg
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