CN101975975B - Zero temperature coefficient optical wave plate and polarization state converter - Google Patents

Abstract

The invention provides multiple zero temperature coefficient optical wave plates or optical wave polarization state converters. The optical wave plate or optical wave polarization state converter is formed by the way that two refractive optical mediums HB1 and HB2 the fast axes of which are mutually vertical or parallel are welded or connected together. The length of HB1 is L1, beat length is LB1, temperature coefficient of beat length is KB1, phase delay of linear polarized light the polarization direction of which is respectively parallel with fast axis and slow axis of HB1 after passing through HB1 is Phi1; the length of HB2 is L2, beat length is LB2, temperature coefficient of beat length is KB2, phase delay of linear polarized light the polarization direction of which is respectively parallel with fast axis and slow axis of HB2 after passing through HB2 is Phi2; the length of optical wave plate and optical wave polarization state converter formed by HB1 and HB2 according to the method is L which is equal to L1+L2, and phase delay theta is Phi1-Phi2 or Phi1+Phi2. When KB1 is different from KB2, the optical wave plate and optical wave polarization state converter designed according to the method provided by the invention have phase delay theta with the temperature coefficient of zero.

Description

Zero-temperature coefficient optical wave plate and polarization state transducer

Technical field

The invention belongs to responsive electronics and sensor field in electronics and the infosystem, and the high voltage of electrician's subject and Super-Current Measurement field, be specifically related to have the various optical wave plates of zero-temperature coefficient, optical-fibre wave plate particularly, this class wave plate is applicable to and need analyzes and the various optical systems of controlling polarization state of light, such as various Fibre Optical Sensors, various full optical fiber type optics or photoeletric measuring system etc.In such optics or electro-optical system, this optical wave plate, such as the polarization state transducer that can be used as wherein, light polarization face spinner, optoisolator, the optical splitter that light splitting is variable, optical attenuator, photoswitch etc.

Background technology

Wave plate is widely used in and need analyzes and the various optical systems of controlling polarization state of light, such as various Fibre Optical Sensors, and various optics or photoeletric measuring system etc.In such optics or electro-optical system, wave plate can be used as polarization state transducer wherein, light polarization face spinner, optoisolator, the optical splitter that light splitting is variable, optical attenuator, photoswitch etc. [1], also can in the satellite light quantum communication of transmission photon polarization state information, follow the tracks of the photon polarization state, realize quantum key coding [2].

Traditional block medium wave plate, control wave plate size and optical axis direction difficulty during making during use and the coupling difficulty of optical fiber, integrated optical wave guide device, is not easy to adopt in the fiber optic system that prevails day by day, developed optical-fibre wave plate for this reason.

Optical-fibre wave plate can be made by the high linear birefringence optical fiber (being called for short HiBi optical fiber) of one section appropriate length, also can be made by the high circular birefringence optical fiber of one section appropriate length.The former sees document [3], [4], [5], and the domestic and international patent of relevant fibre-optic current/voltage sensor, as Chinese patent 01801947.1,01101389.3,01812641.3, (03825967.2 application number), (200510076617.2 application number), (200810056486.5 application number) etc., United States Patent (USP) 5953121,6628869B2,6636321B2,6734657B2,7046867B2,7075286B2,7339680B2,5644397,5987195,6023331,6122415,6122425,6166816,6188811B1,6307632B1,6356351B1,7038786B2,6281672B1,6831749B2,7102757B2 etc.; The latter sees Chinese patent 01112680.9,80107389 (application number), 91107430.9 (application numbers), 200710111969.6 (application numbers), United States Patent (USP) 4943132,5096312,7206468,8810789 etc.

Be example with the HiBi optical-fibre wave plate.If HiBi optical fiber slow axis, fast axle refringence are An, after then the polarization direction is parallel to the two-beam propagation unit length of the fast axle of optical fiber, slow axis respectively, the slow-axis direction optical retardation is in the phase differential (hereinafter referred to as phase delay (retardation)) of quick shaft direction light, and namely the birefringence δ of this optical fiber is:

$\mathrm{\δ}=\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\mathrm{\Δn}$

λ in the formula ₀It is light wave wavelength in a vacuum.Definition

$L_B=\frac{2\mathrm{\π}}{\mathrm{\δ}}=\frac{{\mathrm{\λ}}_0}{\mathrm{\Δn}}$

For this optical fiber is λ for the vacuum medium wavelength ₀The bat of light wave long (be called for short clap long), after then light skimmed over this optical fiber that length is L, phase delay φ (L) was:

$\mathrm{\&phi;}\left(L\right)=\mathrm{\&delta;}\&CenterDot;L=\frac{\mathrm{<figure-callout\; id="2"\; label="L\; L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}{L_B}2\mathrm{\&pi;}---\left(1\right)$

Fig. 1 is the polarization converted function of HiBi optical fiber and the relation of fiber lengths.By (1) formula and Fig. 1 as can be known, to intercept a segment length be L, clap the long L that is _BHiBi optical fiber, a kind of exactly phase differential is φ (L)=2 π L/L _BOptical-fibre wave plate.The existing fiber wave plate is made just like this, so Fig. 1 also is the structure of existing fiber wave plate.The obvious optical-fibre wave plate of making like this, the optical axis direction aligning that block wave plate is run into when not having making, wave plate thickness be the difficulty of processing accurately.

Optical-fibre wave plate is except available one section linear birefringence optical fiber fabrication, and also available one section circular birefringent fiber is made.Chinese patent 80207389,91107430, CN01112680, in the United States Patent (USP) 4943132,5096312,7206468,8810789 application protection or what adopt is exactly the circular birefringent fiber wave plate with specific function.

Because optical-fibre wave plate is one section high birefringence optical fiber, so it is easy to and optical fiber, integrated optical wave guide device coupling, can be widely used in various advanced persons' full fibre system.Loop-type shown in Figure 2 (Loop version) Sagnac interferometer type fibre optic current sensor [5], [6] with reflective (In-line version) [3] shown in Figure 3, [6] Sagnac interferometer type fibre optic current sensor is to adopt optical-fibre wave plate as the typical optical system of critical optical elements.

Among two figure, the 60th, light source, the 61, the 62nd, fiber coupler, the 63rd, the optical-fiber type polarizer, the 64th, phase-modulator, the 65th, photodiode, the 66th, signal processing circuit, the 2, the 3rd, protect the bias tyre Transmission Fibers, 4, the 5th, to these two kinds of optical systems a kind of special fiber wave plate (detailed description is seen below) of playing a crucial role of principle of work, S is the conductor of carrying tested electric current, the 1st, and the sensor fibre circle, 3 ' be reflective optical system.

In these two kinds of fibre optic current sensors, the optic path beyond the sensor fibre circle be that amplitude equates, the mutually perpendicular two kinds of line polarisations in polarization direction; Every kind of line polarisation is changed into two kinds of rotatory polarizations that amplitude equates, sense of rotation is opposite again before entering the sensor fibre circle.Because the magnetic field that tested electric current produces makes the electron magnetic moment in the optical fiber produce around the precession of magnetic field rotation, sense of rotation can only be pointed on the direction of right-handed helix rule regulation of magnetic direction at thumb, this just makes the sense of rotation rotatory polarization identical or opposite with electronics precession direction produce the different frequency shifts of amplitude, thereby causes two kinds of phase differential between the rotatory polarization.After rotatory polarization returns transmission light path changes the mutually perpendicular two kinds of line polarisations in polarization direction into, the phase differential of rotatory polarization is converted to the phase differential of line polarisation, so the measurement problem to current field just changes the measurement problem to line polarisation phase place into, the fibre optic interferometer technology of available maturation realizes.Because line polarisation phase place is convenient to be compensated with voltage modulation type optical waveguide phase-modulator, therefore this fibre optic current sensor is realized operation with closed ring easily, is conducive to improve stability and the measuring accuracy of system again.

These advantages of this fibre optic current sensor all have benefited from the line-circle-line conversion of light polarization, so this conversion of perfect realization is the gordian technique of this fibre optic current sensor.Realize a kind of-quarter-wave optical-fibre wave plate (being called for short λ/4 optical-fibre wave plates or λ/4 wave plates) in the optical-fibre wave plate just of this gordian technique.The effect of optical-fibre wave plate in the contemporary optics system seen some from this.

Though optical-fibre wave plate has above-mentioned advantage and effect, also there is a deadly defect, that birefringence that is exactly this wave plate is not natural formation, different mechanical stress produces but force in two mutually perpendicular directions in optical fiber cross section artificially.Because mechanical stress is to responsive to temperature, so the birefringence of optical-fibre wave plate is also to responsive to temperature, and it is long that this just makes the key parameter one of optical-fibre wave plate clap, thus the responsive to temperature of phase retardation φ just.The temperature coefficient of the phase retardation of most optical-fibre wave plates is for negative, but the temperature coefficient that phase retardation is also arranged is positive optical-fibre wave plate, such as, document [3] and United States Patent (USP) 5987195 introduced, and a kind of relative temperature coefficient of clapping the phase retardation of long very long elliptical core fiber wave plate is 0.1%/℃, during 100 ℃ of temperature variation, the phase retardation of the λ that this optical fiber is made/4 optical-fibre wave plates will change more than 10%, and this will produce serious influence to the identical performance of optics that adopts optical-fibre wave plate.

Be example with Sagnac interferometer type fibre optic current sensor, the temperature characterisitic of λ/4 wave plate phase retardations, be that (another factor is the Verdet constant of sensing head optical fiber for one of the two big factors of this sensor performance stability of influence, see United States Patent (USP) 7425820), this principle of work by this Fibre Optical Sensor of introducing previously can be found out.

The analysis of back will show that also λ/4 wave plate phase retardations vary with temperature the scale-up factor S (being the measurement efficient of system) that not only makes between system's output and the measured signal and descend, and the linearity of S is worsened, and also will bring interference noise.The Verdet constant varies with temperature the linearity that then neither makes S to be worsened, and does not also bring interference noise, and scale-up factor S is descended.So influence in the two big factors of system performance stability, it is more serious that λ/4 wave plate phase retardations change the influence that causes.

During phase retardation φ=90 of λ/4 wave plates °, from the X of Transmission Fibers, the line polarisation of Y-direction, λ/4 wave plates by optical axis direction and Transmission Fibers optical axis direction angle at 45, phase retardation φ=90 °, change the right side, left rotatory polarization respectively into, after returning Transmission Fibers into and out of the sensor fibre circle again, be still X, Y-direction (loop-type, see Fig. 2 (b)) or Y, directions X (reflective, see Fig. 3 (b)) the line polarisation, just both phase differential have produced the variation relevant with tested current field.

The phase retardation of λ/4 wave plates is acted upon by temperature changes when departing from 90 °, and is different when situation and φ=90 °.Line polarisation from the directions X that transmits light path, after this faulty λ/4 wave plates by optical axis direction and Transmission Fibers optical axis direction angle at 45, φ ≠ 90 ° enter the sensor fibre circle, no longer only be converted to a branch of right rotatory polarization, but be converted to the big right rotatory polarization R of a branch of amplitude _XThe left rotatory polarization L little with a branch of amplitude _XSAfter λ/4 wave plates return the transmission light path, for reflective, no longer only be converted to the line polarisation of a branch of Y-direction, but the line polarisation of 4 bundle X, Y-direction: two bundle amplitudes, the Y-direction line polarisation Y that phase place is different _R(from R _X) and Y _SL(from L _XS), two bundle amplitudes, the directions X line polarisation X that phase place is different _SR(from R _X) and X _SSL(from L _XS), shown in Fig. 3 (c).Equally, after returning, the line polarisation of Y-direction also no longer only converts the line polarisation of a branch of directions X to, but two bundle amplitudes, directions X line polarisation X that phase place is different _LWith X _SSR, with two bundle amplitudes, Y-direction line polarisation Y that phase place is different _SLWith Y _SSRIn this 8 bundle back light, has only X _LLight and Y _RInformation after the interference of light is the tested current information that we need, 6 bundle light in addition or cause measuring error, or increase the DC level (seeing United States Patent (USP) 5987195,7038786) of output light in the mode of interference noise.Moreover, this 6 bundle light has also taken X _LLight and Y _RThe energy of light has reduced their interference efficient, thereby has reduced the visibility (Visibility, or claim contrast, contrast) of the detected interference signal of photoelectric device, and the ability that makes system detect small-signal descends.Phase retardation about λ/4 wave plates departs from 90 ° to the quantitative test of this sensor measurement error effect, sees document [3], [5] and United States Patent (USP) 5987195 for details, slightly.

, X, the Y-direction of line of return polarisation need only be exchanged and got final product with reflective identical the analysis of loop-type.

Adopt other optical systems of λ/4 wave plates to also have Fig. 4, optical fiber-block medium mixed optical path voltage sensor shown in Figure 5 and block optical medium voltage sensor etc.In this two figure, the effect of λ/4 wave plates all is to produce 90 ° additional biasing phase place, so that system works is at the highest linearity range of sensitivity.

By top analysis as can be known, under the condition of variation of ambient temperature, keep the ideal value of phase retardation for setting of wave plate, significant to the performance that improves relevant electro-optical system.The existing method that addresses this is that, all can not keep the phase retardation of wave plate not to be acted upon by temperature changes, but departed from phase retardation under the prerequisite of ideal value, the visibility that is interference signal descends, under the situation that the ability of system's detection small-signal descends thereupon, the measuring error that the compensating delay phase change brings is not acted upon by temperature changes accuracy of measurement.

Be example with Sagnac interferometer type fibre optic current sensor, existing compensation λ/4 phase retardations change the method for the measuring error of bringing, and have following three kinds:

(1). the DC level of utilizing output light and λ/4 wave plate phase retardations depart from 90 ° the relevant characteristics of deviation value ε, determine ε by the DC level of detected output light, concern the correction measurement result by the ε that analyzes and measuring error again.See document [3], [5] and laid-open U.S. Patents 5987195 in 1999 of delivering in 1998 for details; What the Chinese patent 200810056486.5 (application number) of the Chinese patent 200510076617.2 (application number) of 2005 applications, application in 2008 adopted also is this method.

(2). with the temperature of temperature sensor monitors λ/4 wave plates and sensor fibre circle, temperature coefficient by λ/4 wave plate phase retardations is determined ε, determine actual Verdet constant value by the temperature coefficient of sensor fibre circle Verdet constant, concern the correction measurement result by measuring error and ε and Verdet constant.See United States Patent (USP) 7425820 for details.

(3). the temperature coefficient that utilizes the Verdet constant is just (0.7 * 10 ^-4/ ℃), the temperature coefficient of λ/4 wave plate phase retardations for negative (such as being-2.2 * 10 to certain oval this temperature coefficient of core HiBi optical fiber ^-4/ ℃) characteristics.When this characteristics made temperature increase, the scale-up factor S between system's output and the measured signal will increase with the variation of Verdet constant, reduced with the variation of λ/4 wave plate phase retardations.The deviation value ε that makes λ/4 wave plate phase retardations under the room temperature is a certain optimal value ε ₀, in the range of temperature of regulation, the Verdet constant changes the complementary result who changes with λ/4 wave plate ε, just can make measuring error within the error range that allows.This method sees document [5], United States Patent (USP) 6734657, Chinese patent 01101389.3 for details.

Also have a kind of λ of compensation/4 wave plate phase retardations to vary with temperature the method for the measuring error that causes in addition, that utilizes the characteristics of optical-fibre wave plate phase retardation relevant with wavelength (dispersion characteristics) exactly, reduces the temperature variant amplitude of wave plate phase retardation by the centre wavelength that changes light source.Change optical source wavelength two kinds of methods are arranged again: utilize the centre wavelength characteristics relevant with temperature of light source, change wavelength by the environment temperature that changes place, light source place; Utilize lightwave filter to change the operation wavelength of wideband light source.This method can only compensate λ/4 wave plate phase retardations and change the error that causes in very little range of temperature, implement also inconvenient, gives no comment, and only first three methods is done further to comment herein.

The leave phase retardation of wave plate of preceding two kinds of methods varies with temperature and produces error ε, and therefore the system that leaves departs from optimum Working, and the scale-up factor S (seing before) that leaves departs from optimum value S _OptBecome S ε, therefore the light path system of leaving produces additional noise, revises S then _ε, eliminate S _εIn the additive error item and the nonlinear factor that produce because of ε.Back a kind of method even make the phase retardation of wave plate depart from ideal value artificially makes system be in non-optimum Working artificially, increases the additional noise that produces therefrom artificially.So these three kinds of methods are all to sacrifice the optimal proportion coefficient S that obtains when optical-fibre wave plate has the ideal delay phase place _OptBe cost, all can not take full advantage of the best-of-breed functionality of system, such as the range of linearity, signal to noise ratio (S/N ratio) etc.

By top explanation as can be known, still there is not the optical-fibre wave plate that a kind of phase retardation is not subjected to influence of temperature change so far; If the phase retardation of optical-fibre wave plate is not subjected to influence of temperature change, one of two big factors that influence the said system performance just will thoroughly be got rid of, and the method that the compensation wave plate phase retardation of existing various complexity changes the measuring error of bringing all need not adopt.Therefore should seek the optical-fibre wave plate that phase retardation is not subjected to influence of temperature change.

Referenced patent

United States Patent (USP): 5953121,6628869B2,6636321B2,6734657B2,7046867B2,7075286B2,7339680B2,5644397,5987195,6023331,6122425,6166816,6188811B1,6307632B1,6356351B1,7038786B2,6281672B1,6831749B2,7102757B2,4943132,5096312,7206468,8810789; Chinese patent: 01801947.1,01101389.3,01812641.3,01112680.9; Chinese patent application: 03825967.2,200510076617.2,200810056486.5,80107389,91107430.9,200710111969.6.

List of references

[1] .Basic Polarization Techniques and Devices, 2005Meadowlark Optics, Inc, see: Http:// www.meadowlark.com/applicationnotes/basic%20polarization %20techniques%20and%20de Vices.pdf

[2]. the horse crystalline substance, Zhang Guangyu, Rong Yiwen, Tan Liying is based on the polarization tracking theoretical analysis of half-wave plate, Acta Physica Sinica, 2006,55 (1): 24-28.

[3].Shayne?X.Short，Alexandr?A.Tselikov，Josiel?U.de?Arruda，and?James?N.Blake，Imperfect?Quarter-Waveplate?Compensation?in?Sagnac?Interferometer-Type?Current?Sensors，Journal?of?Lightwave?Technology，1998，16(7)：1212-1219.

[4].Shayne?X.Short，Josiel?U.de?Arruda，Alexandr?A.Tselikov，and?James?N.Blake，Elimination?of?Birefringence?Induced?Scale?Factor?Errors?in?the?In-Line?Sagnac?Interferometer?Current?Sensor，Journal?of?Lightwave?Technology，1998，16(10)：1844-1850.

[5].K.Bohnert，P.Gabus，J.Nehring，and?H.

，Temperature?and?Vibration?Insensitive?Fiber-Optic?Current?Sensor，Journal?of?Lightwave?Technology，2002，20(2)：267-276.

[6].J.Blake，P.Tantaswadi?and?R.T.de?Carvalho，In-Line?Sagnac?Interferometer?Current?Sensor，IEEE?Trans.Power?Delivery，1996，11(1)：116-121.

Summary of the invention

The objective of the invention is to eliminate temperature variation to the influence of wave plate phase retardation, improve must adopt wave plate the sensitivity of various systems (such as various Fibre Optical Sensors, various optics or photoeletric measuring system), stability, measuring accuracy, and linear working range etc.

One of technical scheme of the present invention provides the optical-fibre wave plate that various phase retardations have zero-temperature coefficient, comprise: a segment length is a kind of HiBi optical fiber HB1 of L1, one segment length is the another kind of HiBi optical fiber HB2 of L2, and described fiber segment HB1 and HB2 are fused into the optical-fibre wave plate FWP that a segment length is L1+L2 so that quick shaft direction is orthogonal.

The temperature coefficient of a kind of phase delay θ of the present invention is zero optical-fibre wave plate or optical polarization transducer (following general designation FWP), comprising: one section birefringence fiber HB1, and another section birefringence fiber HB2; The length of described HB1 fiber segment is L ₁, thermal expansivity is K _L1, clap the long L that is _B1, clapping long temperature coefficient is K _B1The length of described HB2 fiber segment is L ₂, thermal expansivity is K _L2, clap the long L that is _B2, clapping long temperature coefficient is K _B2It is L=L that the fast fast axle perpendicular to described HB1 of described HB2 is fused into a segment length ₁+ L ₂FWP, the length L of described HB1 fiber segment ₁Length L with described HB2 fiber segment ₂Determined by following formula respectively:

${\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_1=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_2}{K_2-K_1}{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B$

${\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_2=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_1}{K_2-K_1}{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B$

In the formula, K ₁=K _B1-K _L1, K ₂=K _B2-K _L2

The temperature coefficient of a kind of phase delay θ of the present invention is zero FWP, comprising: one section birefringence fiber HBp, and another section birefringence fiber HBn; The length of described HBp fiber segment is L _p, thermal expansivity is K _Lp, clap the long L that is _Bp, clapping long temperature coefficient is K _Bp〉=0; The length of described HBn fiber segment is L _n, thermal expansivity is K _Ln, clap the long L that is _Bn, clapping long temperature coefficient is (K _Bn)＜0; It is L=L that the fast axle that the fast axle of HBn is parallel to HBp is fused into a segment length _p+ L _nFWP, the length L of described HBp fiber segment _pLength L with described HBn fiber segment _nDetermined by following formula respectively:

$L_p=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_n}{K_p+K_n}{L}_{\mathrm{Bp}}$

$L_n=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_p}{K_p+K_n}{L}_{\mathrm{Bn}}$

In the formula, K _p=K _Bp-K _Lp, K _n=K _Bn+ K _Ln

Wherein, the bat of described fiber segment HB1 is long to be LB1, and clapping long relative temperature coefficient is KB1, and thermal expansivity is KL1, and the relative phase delay that two bunch polarisations of quick shaft direction parallel for the polarization direction and perpendicular to it produce is φ ₁

Wherein, the bat of described fiber segment HB2 is long to be LB2, and clapping long relative temperature coefficient is KB2, and the relative phase delay that two bunch polarisations of quick shaft direction parallel for the polarization direction and perpendicular to it produce is φ ₂

Wherein, the relative phase delay that produces of described optical-fibre wave plate FWP two bunch polarisations of the quick shaft direction of going into to hold optical fiber (being described fiber segment HB1) parallel for the polarization direction and perpendicular to it is that θ is θ=φ ₁-φ ₂

Two of technical scheme of the present invention provides the optical-fibre wave plate that various phase retardations have zero-temperature coefficient, comprise: a segment length is a kind of HiBi optical fiber HB1 of Lp, one segment length is the another kind of HiBi optical fiber HB2 of Ln, and described fiber segment HB1 and HB2 are fused into the optical-fibre wave plate FWP that a segment length is Lp+Ln so that quick shaft direction is parallel to each other.

Wherein, the bat of described fiber segment HB1 is long to be LBp, and clapping long relative temperature coefficient is KBp 〉=0, and thermal expansivity is KLp, and the relative phase delay that two bunch polarisations of quick shaft direction parallel for the polarization direction and perpendicular to it produce is φ _p

Wherein, the bat of described fiber segment HB2 is long to be LBn, claps long relative temperature coefficient and be that (KBn)＜0, the relative phase delay of two bunch polarisations generation of quick shaft direction parallel for the polarization direction and perpendicular to it is φ _n

Wherein, the relative phase delay that produces of described optical-fibre wave plate FWP two bunch polarisations of the quick shaft direction of going into to hold optical fiber (being described fiber segment HB1) parallel for the polarization direction and perpendicular to it is that θ is θ=φ _p+ φ _n

Three of technical scheme of the present invention provides the block optical medium wave plate that various phase retardations have zero-temperature coefficient, comprise: one section block optical medium BC1 of a kind of birefringence that thickness is L1, one section block optical medium BC2 of another kind of birefringence that thickness is L2, the unusual optical axis of described block optical medium BC1 and BC2 is orthogonal, and all perpendicular to the light wave propagation direction; The long definition of their bat is identical with HiBi optical fiber, i.e. L _B=λ ₀/ Δ n, λ in the formula ₀Be light wave wavelength in a vacuum, Δ n is the λ that this bulk optical medium is for wavelength ₀Refractive index poor of ordinary light, unusual light.

Wherein, the bat of described block optical medium BC1 is long to be LB1, and clapping long relative temperature coefficient is KB1, and thermal expansivity is KL1, and the relative phase delay that two bunch polarisations of quick shaft direction parallel for the polarization direction and perpendicular to it produce is Г ₁

Wherein, the bat of described block optical medium BC2 is long to be LB2, and clapping long relative temperature coefficient is KB2, and the relative phase delay that two bunch polarisations of quick shaft direction parallel for the polarization direction and perpendicular to it produce is Г ₂

Wherein, the relative phase delay θ that produces of described block optical medium wave plate WP two bunch polarisations of the quick shaft direction of going into to hold optical fiber (being described fiber segment HB1) parallel for the polarization direction and perpendicular to it is θ=Г ₁-Г ₂

The invention has the beneficial effects as follows:

(1) wave plate of making according to the present invention, can be used as fiber segment HB1 and fiber segment HB2 by selecting two kinds of appropriate H iBi, or suitable block optical medium is used as BC1 and BC2, make the phase delay θ of optical-fibre wave plate FWP or block optical medium wave plate WP not be acted upon by temperature changes, must adopt the various systems of wave plate (such as various Fibre Optical Sensors thereby improve, various optics or photoeletric measuring system etc.) sensitivity, stability, important performance indexes such as measuring accuracy and linear working range.

When (2) making the optical-fibre wave plate of various phase retardations according to the present invention, there is not the difficulty that optical axis direction is aimed at, wave plate thickness is accurately processed that block wave plate is run into when making.

(3) replace existing wave plate with optical-fibre wave plate of the present invention, can save in the existing system phase retardation for the compensation wave plate and change additional light path, circuit and the corresponding calculation procedure that the measuring error brought adopts, simplify system architecture, reduced system cost, improved the work efficiency of system.

Description of drawings

The invention will be further described below in conjunction with accompanying drawing.

Fig. 1 is after linearly polarized light passes through the existing HiBi optical-fibre wave plate HB (comprising polarization state transducer) of different length, the relation of optical polarization and wave plate length;

Fig. 2 (a) and (b) are respectively the main light channel structures of the loop-type Sagnac interferometer type fibre optic current sensor that plays a crucial role of λ/4 optical-fibre wave plates, polarization converted synoptic diagram in light path during and desirable λ/4 optical-fibre wave plates.

Fig. 3 (a) and (b), (c) are respectively the main light channel structures of the reflective Sagnac interferometer type fibre optic current sensor that plays a crucial role of λ/4 optical-fibre wave plates, polarization converted synoptic diagram in light path during and desirable, irrational λ/4 optical-fibre wave plates.

Fig. 4 (a) and (b), (c) are respectively the application of λ/4 wave plates in reflecting light fibre voltage sensor and optical fiber-block medium mixed type voltage sensor.Among the figure: the 11st, light source, the 12nd, photo-coupler, the 13rd, the polarizer, 14, the 16th, polarization maintaining optical fibre, 15 provide the phase-modulator of biasing and feedback phase, the 17th, the electrooptical effect sensor of the tested local voltage of sensing, the 18th, polarization maintaining optical fibre lag line, the 19th, λ/4 optical-fibre wave plates, the 20th, reflective optical system, 21,40, the 41st, photoelectric commutator, the 22nd, closed-loop signal processor, the 23rd, integrator, the 25th, Faraday rotator, the 26th, open-loop signal processor, 29 represent the not offset light that light source sends, the 30th, the linearly polarized light after rising partially, 31, the 37th, optical splitter, 32,33,34,36,38,39 represent the linearly polarized light of out of phase, 35, the 46th, λ/4 wave plates, the 42nd, signal processor, the 45th, measured voltage indicator.

Fig. 5 is the application of λ/4 wave plates in the voltage sensor that adopts block optical medium.

Fig. 6 (a) and (b) are respectively that the fast axle, slow axis of a kind of HiBi optical-fibre wave plate structure of the present invention and wave plate are with respect to the orientation of incident light X, Y polarization direction.

Fig. 7 (a) and (b) are respectively that the fast axle, slow axis of a kind of tc compensation type HiBi optical-fibre wave plate structure of the present invention and wave plate are with respect to the orientation of incident light X, Y polarization direction.

Fig. 8 is the orientation of ordinary optical axis (o light), unusual optical axis (e light) in the optical wave plate WP structure of two optical crystals of a kind of employing of the present invention and two crystal, wherein, and BC1 and BC2 or be all positive crystal, or be all negative crystal.

Fig. 9 is the orientation of ordinary optical axis (o light), unusual optical axis (e light) in a kind of optical wave plate WP structure that adopts positive crystal and negative crystal of the present invention and two crystal, and wherein, BC3 and BC4 must one is positive crystal, and another is negative crystal.

Figure 10 (d), (b) are respectively the measurement curves that the phase retardation (ordinate) of two kinds of HiBi optical-fibre wave plates providing of document [5], document [3] changes with environment temperature (horizontal ordinate), the temperature coefficient of the former phase retardation is negative (clap long temperature coefficient for just), and the temperature coefficient of the latter's phase retardation be just (clapping long temperature coefficient is to bear).

Figure 11 is by method provided by the invention, claps long L according to used HiBi optical fiber _B1, L _B2, temperature coefficient K ₁, K ₂Or K _B1, K _B2, and the phase retardation θ that requires, several temperatures coefficient of designing are the geometric parameter L of zero optical-fibre wave plate ₁, L ₂Example.

Figure 12 is the phase retardation of optical-fibre wave plate of the present invention and the relation curve of environment temperature.

Embodiment

Embodiment 1

Fig. 6 is the basic embodiment 1 according to the inventive method, and wherein (a) is optical-fibre wave plate of the present invention or optical fiber polarisation attitude transducer (general designation FWP) structural representation, (b) is that the fast axle, slow axis of FWP are with respect to the orientation maps of incident light X, Y polarization direction.Among Fig. 6 (a), HB1 is that length is L ₁One section HiBi optical fiber, the thermal expansivity of this optical fiber is K _L1, clap the long L that is _B1, clapping long temperature coefficient is K _B1HB2 is that length is L ₂Another kind of HiBi optical fiber, the thermal expansivity of this optical fiber is K _L2, clap the long L that is _B2, clapping long temperature coefficient is K _B2It is L=L that the fast fast axle perpendicular to HB1 of HB2 is fused into a segment length ₁+ L ₂FWP (all in random order for HB1, HB2).

One bunch polarisation is decomposed into the X-ray that the polarization direction is parallel to the fast axle of HB1 F1 pass through HB1 with the Y light that the polarization direction is parallel to HB1 slow axis S1 after, the phase place of X-ray will be ahead of Y light.By (1) formula, leading phase mass, i.e. phase delay φ between X-ray and the Y light ₁(L) be:

${\mathrm{\&phi;}}_1=\frac{L_1}{{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}---\left(2\right)$

Do not exist at HB1 under the situation of circular birefringence, the Jones matrix of HiBi fiber segment HB1 correspondence is (seeing document [4]):

${\mathrm{<figure-callout\; id="1"\; label="J"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">J</figure-callout>}}_1=\left[\begin{array}{cc}{e}^{{\mathrm{j\&phi;}}_1/2}& 0\\ 0& e^{-j{\mathrm{\&phi;}}_1/2}\end{array}\right]$

In like manner, axle F2, Y polarisation of light direction are parallel under the situation of HB2 slow axis S2 phase delay (retardation) φ that HB2 produces soon to be parallel to HB2 in the polarization direction of X-ray ₂(L) and corresponding Jones matrix J ₂Be respectively:

${\mathrm{\&phi;}}_2=\frac{L_2}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}---\left(3\right)$

${\mathrm{<figure-callout\; id="1"\; label="J"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">J</figure-callout>}}_1=\left[\begin{array}{cc}{e}^{{\mathrm{j\&phi;}}_2/2}& 0\\ 0& e^{-j{\mathrm{\&phi;}}_2/2}\end{array}\right]$

If the polarization direction of X-ray is parallel to HB2 slow axis S2, Y polarisation of light direction is parallel to the fast axle of HB2 F2, the Jones matrix of HB2 correspondence at this moment then

For:

${\tilde{J}}_2=\left[\begin{array}{cc}{e}^{{-\mathrm{j\&phi;}}_2/2}& 0\\ 0& e^{j{\mathrm{\&phi;}}_2/2}\end{array}\right]={{\mathrm{<figure-callout\; id="2"\; label="J"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">J</figure-callout>}}_2}^{*}$

* represents complex conjugate in the formula.The embodiment of the invention 1 belongs to latter event, and namely X-ray is parallel to the S2 axle, and the Y parallel light is in the F2 axle, and therefore the wave plate of being made up of HB1, HB2 for the X-ray of incident, the Jones matrix J of Y light is:

$J={{\mathrm{<figure-callout\; id="2"\; label="J"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">J</figure-callout>}}_2}^{*}\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="J"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">J</figure-callout>}}_1=\left[\begin{array}{cc}{e}^{-j{\mathrm{\&phi;}}_2/}& 0\\ 0& e^{j{\mathrm{\&phi;}}_2/2}\end{array}\right]\left[\begin{array}{cc}{e}^{j{\mathrm{\&phi;}}_1/2}& 0\\ 0& e^{-j{\mathrm{\&phi;}}_1/2}\end{array}\right]$

$=\left[\begin{array}{cc}{e}^{j({\mathrm{\&phi;}}_1-{\mathrm{\&phi;}}_2/)2}& 0\\ 0& e^{-j({\mathrm{\&phi;}}_1-{\mathrm{\&phi;}}_2)/2}\end{array}\right]=\left[\begin{array}{cc}{e}^{\mathrm{j\&theta;}/2}& 0\\ 0& e^{-\mathrm{j\&theta;}/2}\end{array}\right]---\left(4\right)$

In the formula

$\mathrm{\&theta;}={\mathrm{\&phi;}}_1-{\mathrm{\&phi;}}_2=\frac{L_1}{{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}-\frac{L_2}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}---\left(5\right)$

It is exactly the phase retardation of optical-fibre wave plate shown in Figure 6.According to (2), (3) two formulas, φ ₁, φ ₂Rate of temperature change be respectively:

$\frac{1}{{\mathrm{\&phi;}}_1}\frac{{\mathrm{d\&phi;}}_1}{\mathrm{dT}}=-\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}\frac{{\mathrm{<figure-callout\; id="1"\; label="dL\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">dL</figure-callout>}}_B}{\mathrm{dT}}+\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\frac{{\mathrm{<figure-callout\; id="1"\; label="dL"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">dL</figure-callout>}}_1}{\mathrm{dT}}=-{\mathrm{<figure-callout\; id="1"\; label="K\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">K</figure-callout>}}_B+{\mathrm{<figure-callout\; id="1"\; label="K\; L"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">K</figure-callout>}}_L=-{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">K</figure-callout>}}_1$

$\frac{1}{{\mathrm{\&phi;}}_2}\frac{{\mathrm{d\&phi;}}_2}{\mathrm{dT}}=-\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}\frac{{\mathrm{<figure-callout\; id="2"\; label="dL\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">dL</figure-callout>}}_B}{\mathrm{dT}}+\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}\frac{{\mathrm{<figure-callout\; id="2"\; label="dL"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">dL</figure-callout>}}_2}{\mathrm{dT}}=-{\mathrm{<figure-callout\; id="2"\; label="K\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_B+{\mathrm{<figure-callout\; id="2"\; label="K\; L"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_L=-{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_2$

In the formula, K _B1, K _L1Be the long temperature coefficient of bat and the thermal expansivity of HB1 optical fiber, K _B2, K _L2Be the long temperature coefficient of bat and the thermal expansivity of HB2 optical fiber:

${\mathrm{<figure-callout\; id="1"\; label="K\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">K</figure-callout>}}_B=\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}\frac{{\mathrm{<figure-callout\; id="1"\; label="dL\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">dL</figure-callout>}}_B}{\mathrm{dT}},{\mathrm{<figure-callout\; id="2"\; label="K\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_B=\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}\frac{{\mathrm{<figure-callout\; id="2"\; label="dL\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">dL</figure-callout>}}_B}{\mathrm{dT}},$

${\mathrm{<figure-callout\; id="1"\; label="K\; L"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">K</figure-callout>}}_L=\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\frac{{\mathrm{<figure-callout\; id="1"\; label="dL"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">dL</figure-callout>}}_1}{\mathrm{dT}},{\mathrm{<figure-callout\; id="2"\; label="K\; L"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_L=\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}\frac{{\mathrm{<figure-callout\; id="2"\; label="dL"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">dL</figure-callout>}}_2}{\mathrm{dT}}=\frac{1}{L}\frac{\mathrm{dL}}{\mathrm{dT}}$

K ₁＝K _B1-K _L1，K ₂＝K _B2-K _L2

A kind of design-calculated approach of simplifying this optical-fibre wave plate is: HB1, HB2 make with the HiBi optical fiber of glass of fiber core material identical (such as fused silica glass), at this moment,

K _L1＝K _L2＝K _L，K ₁＝K _B1-K _L，K ₂＝K _B2-K _L

By (2), (3), (5) three formulas, during temperature variation Δ T, φ ₁, φ ₂And the variation of Fig. 6 optical-fibre wave plate FWP phase retardation θ is respectively:

${\mathrm{\&Delta;\&phi;}}_1=\frac{1}{{\mathrm{\&phi;}}_1}\frac{{\mathrm{d\&phi;}}_1}{\mathrm{dT}}{\mathrm{\&phi;}}_1\&CenterDot;\mathrm{\&Delta;t}=-{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">K</figure-callout>}}_1\&CenterDot;{\mathrm{\&phi;}}_1\&CenterDot;\mathrm{\&Delta;T}=-K_1\frac{L_1}{{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}\&CenterDot;\mathrm{\&Delta;T}$

${\mathrm{\&Delta;\&phi;}}_2=-K_2\frac{L_2}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}\&CenterDot;\mathrm{\&Delta;T}$

$\mathrm{\&Delta;\&theta;}=\mathrm{\&Delta;}({\mathrm{\&phi;}}_1-{\mathrm{\&phi;}}_2)={\mathrm{\&Delta;\&phi;}}_1-{\mathrm{\&Delta;\&phi;}}_2=2\mathrm{\&pi;}(K_2\frac{L_2}{L_{B2}}-K_1\frac{L_1}{L_{B1}})\&CenterDot;\mathrm{\&Delta;T}$

Got by above three formulas:

$\frac{{\mathrm{\&Delta;\&phi;}}_1}{\mathrm{\&Delta;T}}=-K_1\frac{L_1}{{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}---\left(6\right)$

$\frac{{\mathrm{\&Delta;\&phi;}}_2}{\mathrm{\&Delta;T}}=-K_2\frac{L_2}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}---\left(7\right)$

$\frac{\mathrm{\&Delta;\&theta;}}{\mathrm{\&Delta;T}}=2\mathrm{\&pi;}(K_2\frac{L_2}{L_{B2}}-K_1\frac{L_1}{L_{B1}})---\left(8\right)$

By above analysis, θ is not acted upon by temperature changes must guarantees following two formulas establishment simultaneously:

$\frac{L_1}{{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}-\frac{L_2}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}2\mathrm{\&pi;}=\mathrm{\&theta;}---\left(9\right)$

$K_1\frac{L_1}{L_{B1}}-K_2\frac{L_2}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}=0---\left(10\right)$

Above two formulas of simultaneous solution get:

${\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_1=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_2}{K_1-K_1}{L}_{B1}---\left(11\right)$

${\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_2=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_1}{K_2-K_1}{L}_{B2}---\left(12\right)$

$\frac{L_1}{{\mathrm{<figure-callout\; id="1"\; label="L\; B"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_2}{K_2-K_1}---\left(13\right)$

$\frac{L_2}{{\mathrm{<figure-callout\; id="2"\; label="L\; B"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_B}=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_1}{K_2-K_1}---\left(14\right)$

(13), (14) two formula substitution (8) formulas are got:

$\frac{\mathrm{\&Delta;\&theta;}}{\mathrm{\&Delta;T}}=2\mathrm{\&pi;}(K_2\frac{L_2}{L_{B2}}-K_1\frac{L_1}{L_{B1}})=\mathrm{\&theta;}(\frac{K_2{K}_1}{K_2-K_1}-\frac{K_1{K}_2}{K_2-K_1})=0---\left(15\right)$

When HB1, HB2 make with the HiBi optical fiber of glass of fiber core material identical (such as fused silica glass), K _L1=K _L2=K _L, K ₁=K _B1-K _L, K ₂=K _B2-K _L, L at this moment ₁, L ₂Design formula be reduced to:

${\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_1=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_2}{K_{B2}-K_{B1}}{L}_{B1}---(11-1)$

${\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_2=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_1}{K_{B2}-K_{B1}}{L}_{B2}---(12-1)$

Generally speaking, K _L≈ 10 ^-6, K _B≈ 10 ^-4～10 ^-3, K ₁=K _B1-K _L≈ K _B1, K ₂=K _B2-K _L≈ K _B2, L at this moment ₁, L ₂Design formula be reduced to:

${\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000278696000081.png,HSA00000278696000111.png"\; state="\{\{state\}\}">L</figure-callout>}}_1=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_{B2}}{K_{B2}-K_{B1}}{L}_{B1}---(11-2)$

${\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_2=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_{B1}}{K_{B2}-K_{B1}}{L}_{B2}---(12-2)$

According to the long temperature coefficient long with bat of the bat of selected HiBi, calculate the length L of HB1 by above formula ₁Length L with HB2 ₂, press the optical-fibre wave plate that Fig. 6 constitutes then, be exactly phase retardation be θ=φ ₁-φ ₂, the temperature coefficient of θ is 0 optical-fibre wave plate.

By (11)～(12-2) formula as can be known, K ₂＞K ₁Or K _B2＞K _B1The time, θ＞0, K ₂＜K ₁Or K _B2＜K _B1The time, θ＜0.

Figure 11 is as stated above, claps long L according to used HiBi optical fiber _B1, L _B2, temperature coefficient K ₁, K ₂Or K _B1, K _B2, and the phase retardation θ that requires, several temperatures coefficient of designing are the geometric parameter L of zero optical-fibre wave plate ₁, L ₂Example.

Figure 12 (a) is the related parameter that has by λ/4 optical-fibre wave plates of this patent method design, (b) is the phase retardation φ of HB1 section ₁, the HB2 section phase retardation φ ₂, wave plate the temperature variant curve of phase retardation θ.The parameter of HB1 section HiBi optical fiber identical with Figure 10 (a) (seeing document [5]): L _B1=3.0mm, K _B1=2.2 * 10 ^-4/ ℃; The parameter of HB2 section HiBi optical fiber is: L _B2=3.6mm, K _B2=1.5K _B1=3.3 * 10 ^-4/ ℃, the L that designs ₁=2.25mm, φ ₁=270 °, L ₂=1.8mm, φ 2=180 °, θ=φ ₁-φ ₂=90 °, Δ φ ₁/ Δ T=Δ φ ₂/ Δ T=-1.037 * 10 ^-3Rad./℃=-0.0594 °/℃.

Embodiment 2

Fig. 7 is the basic embodiment of temperature complementary type FWP according to the inventive method, and wherein (a) is the structural representation of this FWP, (b) is that the fast axle, slow axis of FWP are with respect to the orientation maps of incident light X, Y polarization direction.Among Fig. 7 (a), HBp is that length is L _pOne section HiBi optical fiber, the thermal expansivity of this optical fiber is K _Lp, clap the long L that is _Bp, clapping long temperature coefficient is K _Bp〉=0; HBn is that length is L _nAnother kind of HiBi optical fiber, the thermal expansivity of this optical fiber is K _Ln, clap the long L that is _Bn, clapping long temperature coefficient is (K _Bn)＜0.It is L=L that the fast axle that the fast axle of HBn is parallel to HBp is fused into a segment length _ρ+ L _nTemperature complementary type FWP (all in random order for HBp, HBn).

The analysis of imitative embodiment 1, at this moment

$\mathrm{\&theta;}={\mathrm{\&phi;}}_p+{\mathrm{\&phi;}}_n=\frac{L_{\mathrm{<figure-callout\; id="2"\; label="p\; L\; Bp"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">p</figure-callout>}}}{L_{\mathrm{Bp}}}2\mathrm{\&pi;}+\frac{L_{\mathrm{<figure-callout\; id="2"\; label="n\; L\; Bn"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">n</figure-callout>}}}{L_{\mathrm{Bn}}}2\mathrm{\&pi;}---\left(13\right)$

$\frac{1}{{\mathrm{\&phi;}}_p}\frac{{\mathrm{d\&phi;}}_p}{\mathrm{dT}}=-\frac{1}{L_{\mathrm{Np}}}\frac{{\mathrm{dL}}_{\mathrm{Bp}}}{\mathrm{dT}}+\frac{1}{L_p}\frac{{\mathrm{dL}}_p}{\mathrm{dT}}=-K_{\mathrm{Bp}}+K_{\mathrm{Lp}}=-K_p$

$\frac{1}{{\mathrm{\&phi;}}_n}\frac{{\mathrm{d\&phi;}}_n}{\mathrm{dT}}=-\frac{1}{L_{\mathrm{Bn}}}\frac{{\mathrm{dL}}_{\mathrm{Bn}}}{\mathrm{dT}}+\frac{1}{L_n}\frac{{\mathrm{dL}}_n}{\mathrm{dT}}=K_{\mathrm{Bn}}+K_{\mathrm{Ln}}=K_n$

In the formula,

K _p＝K _Bp-K _Lp，K _n＝K _Bn+K _Ln

And K _p, K _n(note: the long temperature coefficient of the bat of HBn fiber segment is (K to be positive number _BnSo)＜0 is K _Bn＞0)

When HBp, HBn make with the HiBi optical fiber of glass of fiber core material identical (such as fused silica glass), K _Lp=K _Ln=K _L,

K _p＝K _Bp-K _L，K _n＝K _Bn+K _L

During temperature variation Δ T, φ _p, φ _nAnd the variation of Fig. 7 optical-fibre wave plate FWP phase retardation θ is respectively:

${\mathrm{\&Delta;\&phi;}}_p=\frac{1}{{\mathrm{\&phi;}}_p}\frac{{\mathrm{d\&phi;}}_p}{\mathrm{dT}}{\mathrm{\&phi;}}_p\&CenterDot;\mathrm{\&Delta;T}=-K_p\&CenterDot;{\mathrm{\&phi;}}_p\&CenterDot;\mathrm{\&Delta;T}=-K_p\frac{L_{\mathrm{<figure-callout\; id="2"\; label="p\; L\; Bp"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">p</figure-callout>}}}{L_{\mathrm{Bp}}}2\mathrm{\&pi;}\&CenterDot;\mathrm{\&Delta;T}$

${\mathrm{\&Delta;\&phi;}}_n=K_n\frac{L_{\mathrm{<figure-callout\; id="2"\; label="n\; L\; Bn"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">n</figure-callout>}}}{L_{\mathrm{Bn}}}2\mathrm{\&pi;}\&CenterDot;\mathrm{\&Delta;T}$

$\frac{\mathrm{\&Delta;\&theta;}}{\mathrm{\&Delta;T}}=\frac{{\mathrm{\&Delta;\&phi;}}_p}{\mathrm{\&Delta;T}}+\frac{{\mathrm{\&Delta;\&phi;}}_n}{\mathrm{\&Delta;T}}=2\mathrm{\&pi;}(K_n\frac{L_n}{L_{\mathrm{Bn}}}-K_p\frac{L_p}{L_{\mathrm{Bp}}})---\left(14\right)$

At this moment keep θ not become by the condition of influence of temperature change:

$\frac{L_p}{L_{\mathrm{Bp}}}+\frac{L_n}{L_{\mathrm{Bn}}}=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}---\left(15\right)$

$K_n\frac{L_n}{L_{\mathrm{Bn}}}-K_p\frac{L_p}{L_{\mathrm{Bp}}}=0---\left(16\right)$

Above two formulas of simultaneous solution get:

$\frac{L_p}{L_{\mathrm{Bp}}}=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_n}{K_p+K_n}---\left(17\right)$

$\frac{L_n}{L_{\mathrm{Bn}}}=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_p}{K_p+K_n}---\left(18\right)$

(17), (18) two formula substitution (14) formulas are got:

$\frac{\mathrm{\&Delta;\&theta;}}{\mathrm{\&Delta;T}}=2\mathrm{\&pi;}(K_n\frac{L_n}{L_{\mathrm{Bn}}}-K_p\frac{L_p}{L_{\mathrm{Bp}}})=\mathrm{\&theta;}(\frac{K_n{K}_p}{K_p+K_n}-\frac{K_p{K}_n}{K_p+K_n})=0---\left(19\right)$

Design example:

With L _Bp=3.0mm, K _Lp≈ K _Bp=(1/L _Bp) (dL _Bp/ dT)=-(1/ φ _p) (d φ _p/ dT)=2.2 * 10 ^-4/ ℃ HiBi optical fiber (see Figure 11 (a) with document [5]) be HBp, with L _Bn=32.64mm, K _Ln≈ K _Bn=-(1/ φ _n) (d φ _n/ dT)=-1.0 * 10 ^-3/ ℃ HiBi optical fiber (see Figure 11 (b) with document [3]) be HBn, design temperature complementary type single order λ/4 wave plates, i.e. λ/4 wave plates of θ=(2n+1) * pi/2=3 * pi/2.

Design result:

$\frac{L_p}{L_{\mathrm{Bp}}}=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_n}{K_p+K_n}=\frac{3}{4}\&times;\frac{1}{1.22}$

$L_p=\frac{L_p}{L_{\mathrm{Bp}}}\&times;L_{\mathrm{Bp}}=\frac{3}{4}\&times;\frac{1}{1.22}\&times;3\mathrm{mm}\&ap;1.8426\mathrm{mm}$

$\frac{L_n}{L_{\mathrm{Bn}}}=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_p}{K_p+K_n}=\frac{3}{4}\&times;\frac{0.22}{1.22}$

$L_n=\frac{L_n}{L_{\mathrm{Bn}}}\&times;L_{\mathrm{Bn}}=\frac{3}{4}\&times;\frac{0.22}{1.22}\&times;32.64\mathrm{mm}\&ap;4.4144\mathrm{mm}$

Check:

$\mathrm{\&theta;}={\mathrm{\&phi;}}_p+{\mathrm{\&phi;}}_n=\frac{L_{\mathrm{<figure-callout\; id="2"\; label="p\; L\; Bp"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">p</figure-callout>}}}{L_{\mathrm{Bp}}}2\mathrm{\&pi;}+\frac{L_{\mathrm{<figure-callout\; id="2"\; label="n\; L\; Bn"\; filenames="HSA00000278696000011.png,HSA00000278696000031.png"\; state="\{\{state\}\}">n</figure-callout>}}}{L_{\mathrm{Bn}}}2\mathrm{\&pi;}=\frac{3}{4}\&times;(\frac{1}{1.22}+\frac{0.22}{1.22})\&times;2\mathrm{\&pi;}=3\mathrm{\&pi;}/2$

Embodiment 3

Fig. 8 is according to basic embodiment 2 of the present invention, wherein BC1 is that thickness is a kind of positive crystal (or negative crystal) birefringence optics medium of L1 on the optical propagation direction, BC2 is that thickness is another kind of positive crystal (or negative crystal) the birefringence optics medium of L2 on the optical propagation direction, the optical axis of BC1, BC2 is orthogonal, and all perpendicular to optical propagation direction.When L1, L2 satisfy formula (11), (12), or (11-1), (12-1), or (11-2), during the requiring of (12-2), the phase retardation that BC1, BC2 form is that the temperature coefficient of the wave plate of θ is zero.

Embodiment 4

Fig. 9 is according to basic embodiment 3 of the present invention, wherein BC3 is that thickness is a kind of positive crystal (or negative crystal) birefringence optics medium of L1 on the optical propagation direction, BC4 is that thickness is a kind of negative crystal (positive crystal) birefringence optics medium of L2 on the optical propagation direction, the optical axis of BC3, BC4 is parallel to each other, and perpendicular to optical propagation direction.When L1, L2 satisfy formula (11), (12), or (11-1), (12-1), or (11-2), during the requiring of (12-2), the phase retardation that BC3, BC4 form is that the temperature coefficient of the wave plate of θ is zero.

Invention has been described according to specific exemplary embodiment herein.It will be apparent carrying out suitable replacement to one skilled in the art or revise under not departing from the scope of the present invention.Exemplary embodiment only is illustrative, rather than to the restriction of scope of the present invention, scope of the present invention is by appended claim definition.

Claims (20)

1. the temperature coefficient of a phase delay θ is zero optical-fibre wave plate, comprising: one section birefringence fiber HB1, and another section birefringence fiber HB2; The length of described HB1 fiber segment is L ₁, thermal expansivity is K _L1, clap the long L that is _B1, clapping long temperature coefficient is K _B1The length of described HB2 fiber segment is L ₂, thermal expansivity is K _L2, clap the long L that is _B2, clapping long temperature coefficient is K _B2It is L=L that the fast fast axle perpendicular to described HB1 of described HB2 is fused into a segment length ₁+ L ₂Optical-fibre wave plate, the length L 1 of described HB1 fiber segment is determined by following formula respectively with the length L 2 of described HB2 fiber segment:

$L_1=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_2}{K_2-K_1}{L}_{B1}$

$L_2=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_1}{K_2-K_1}{L}_{B2}$

In the formula, K ₁=K _B1-K _L1, K ₂=K _B2-K _L2

2. optical-fibre wave plate as claimed in claim 1 is characterized in that the long temperature coefficient K of bat of described fiber segment HB1, HB2 _B1With K _B2Be negative value.

3. optical-fibre wave plate as claimed in claim 1 is characterized in that the long temperature coefficient K of bat of described fiber segment HB1, HB2 _B1With K _B2Be on the occasion of.

4. the temperature coefficient of a phase delay θ is zero optical-fibre wave plate, comprising: one section birefringence fiber HBp, and another section birefringence fiber HBn; The length of described HBp fiber segment is L _p, thermal expansivity is K _Lp, clap the long L that is _Bp, clapping long temperature coefficient is K _Bp〉=0; The length of described HBn fiber segment is L _n, thermal expansivity is K _Ln, clap the long L that is _Bn, clapping long temperature coefficient is (K _Bn)＜0; It is L=L that the fast axle that the fast axle of HBn is parallel to HBp is fused into a segment length _p+ L _nOptical-fibre wave plate, the length L of described HBp fiber segment _pLength L with described HBn fiber segment _nDetermined by following formula respectively:

$L_p=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_n}{K_p+K_n}{L}_{\mathrm{Bp}}$

$L_n=\frac{\mathrm{\&theta;}}{2\mathrm{\&pi;}}\frac{K_p}{K_p+K_n}{L}_{\mathrm{Bn}}$

In the formula, K _p=K _Bp-K _Lp, K _n=K _Bn+ K _Ln

5. the temperature coefficient that constitutes as each described optical-fibre wave plate among the claim 1-4 is λ/4 wave plates of zero, it is characterized in that phase delay θ=(2n+1) * 90 °, wherein n is integer, the line polarisation at the fast axle angle at 45 of polarization direction and described wave plate is by behind the described wave plate, and emergent light is left rotatory polarization; Left side rotatory polarization is by behind the described wave plate, and emergent light is the line polarisation at the fast axle angle at 45 of polarization direction and described wave plate.

6. the temperature coefficient that constitutes as each described optical-fibre wave plate among the claim 1-4 is λ/4 wave plates of zero, it is characterized in that phase delay θ=-(2n+1) * 90 °, wherein n is integer, the line polarisation at the fast axle angle at 45 of polarization direction and described wave plate is by behind the described wave plate, and emergent light is right rotatory polarization; Right rotatory polarization is by behind the described wave plate, and emergent light is the line polarisation at the fast axle angle at 45 of polarization direction and described wave plate.

7. the temperature coefficient that constitutes as each described optical-fibre wave plate among the claim 1-4 is zero half-wave plate, it is characterized in that phase delay θ=(2n+1) * 180 °, wherein n is integer, during the fast axle of described wave plate and X or Y-direction angle at 45, the line polarisation of X or Y-direction is by behind the described wave plate, and emergent light is the line polarisation of Y-direction or directions X.

8. the temperature coefficient that constitutes as each described optical-fibre wave plate among the claim 1-4 is zero optical polarization transducer, it is characterized in that phase delay θ ≠ ± (2n+1) * 90 ° and ± (2n+1) * 180 °, wherein n is integer, described optical polarization transducer can be according to different phase-delay values, change the line polarisation of different directions the elliptically polarized light of different ovalitys, different major axis or short-axis direction into, or the elliptically polarized light of different ovalitys, different major axis or short-axis direction is changed into the line polarisation of different polarization direction.

9. one kind is the line polarisation isolator that zero λ/4 wave plates, the line polarisation polarizer and reflective optical system formed by claim 5 or 6 described temperatures coefficient, it is characterized in that described λ/4 wave plates between the described polarizer and described reflective optical system, the fast axle angle at 45 of the polarization direction of the described polarizer and described λ/4 wave plates; After the line polarisation of any direction entered described optoisolator, the amplitude of the emergent light that returns was zero.

10. one kind is transformed to right rotatory polarization by what half-wave plate constituted with left rotatory polarization, or right rotatory polarization is transformed to the optical polarization transducer of left rotatory polarization, it is characterized in that described half-wave plate is that the temperature coefficient described in the claim 7 is zero half-wave plate.

11. a temperature coefficient is zero optical wave plate, it is characterized in that: this optical wave plate is that described HB1, HB2 in the described optical-fibre wave plate of claim 1 are replaced with the mutually perpendicular block optical medium of optical axis, and all is positive optical axis crystal.

12. a temperature coefficient is zero optical wave plate, it is characterized in that: this optical wave plate is that described HB1, HB2 in the described optical-fibre wave plate of claim 1 are replaced with the mutually perpendicular block optical medium of optical axis, and all is negative optical axis crystal.

13. a temperature coefficient is zero optical wave plate, it is characterized in that: this optical wave plate is that described HB1, HB2 in the described optical-fibre wave plate of claim 1 are replaced with optical axis block optical medium parallel to each other, and HB1 is that negative crystal and HB2 are positive crystals, and perhaps HB1 is that positive crystal and HB2 are negative crystal.

14. the temperature coefficient of a phase delay θ is zero composite fiber wave plate, comprising: n is zero optical-fibre wave plate as each described temperature coefficient of claim 1-4, and described phase delay θ is the phase delay θ of n optical-fibre wave plate _iSum, wherein i=1,2 ... n, n are integer.

15. the temperature coefficient of a phase delay θ is zero optical wave plate, comprising: n is zero optical wave plate as each described temperature coefficient of claim 11-13, and described phase delay θ is the phase delay θ of n optical wave plate _iSum, wherein i=1,2 ... n, n are integer.

16. a loop-type Sagnac interferometer type fibre optic current sensor is characterized in that: comprising as claim 5, or the described temperature coefficient of claim 6 is λ/4 wave plates of zero.

17. a reflective Sagnac interferometer type fibre optic current sensor is characterized in that: comprising as claim 5, or the described temperature coefficient of claim 6 is λ/4 wave plates of zero.

18. a reflection type optical fibre voltage sensor is characterized in that: comprising as claim 11, or claim 12, or the described temperature coefficient of claim 13 is zero optical wave plate.

19. optical fiber-block medium mixed type voltage sensor is characterized in that: comprising as claim 11, or claim 12, or the described temperature coefficient of claim 13 is zero optical wave plate.

20. a block medium mixed-voltage sensor is characterized in that: comprising claim 11, or claim 12, or the described temperature coefficient of claim 13 is zero optical wave plate.

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