CN204330856U - The polarization error restraining device of the Y waveguide loop of optical fiber current mutual inductor - Google Patents
The polarization error restraining device of the Y waveguide loop of optical fiber current mutual inductor Download PDFInfo
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- CN204330856U CN204330856U CN201520015690.8U CN201520015690U CN204330856U CN 204330856 U CN204330856 U CN 204330856U CN 201520015690 U CN201520015690 U CN 201520015690U CN 204330856 U CN204330856 U CN 204330856U
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Abstract
The utility model provides a kind of polarization error restraining device of Y waveguide loop of optical fiber current mutual inductor, belongs to technical field of optical fiber sensing.Y waveguide loop is realized by Y waveguide phase-modulator and polarization beam apparatus, two output tail optical fibers of Y waveguide phase-modulator input tail optical fiber with fusing point 2 with two of polarization beam apparatus respectively by fusing point 1 and are connected, two tail optical fibers that two tail optical fibers connected by fusing point 1 are connected with by fusing point 2 form the two-arm of Y waveguide loop respectively, Y waveguide loop two-arm Length discrepancy, arm length difference is △ L.The input tail optical fiber of Y waveguide phase-modulator is connected with circulator, and the output tail optical fiber of polarization beam apparatus is connected with guarantor's off-delay fiber optic loop.The utility model can reduce optical path loss further, reduces the shot noise of detector, improves the small current measurement precision of mutual inductor; By suppressing the polarization error of Y waveguide loop, can further improve the stability of small current measurement precision.
Description
Technical field
The utility model relates to a kind of polarization error restraining device of Y waveguide loop of optical fiber current mutual inductor, belongs to technical field of optical fiber sensing.
Background technology
Based on the all-fiber current transformator of Faraday effect because of its principal advantage, be acknowledged as the substitute of traditional electrical magnetic inductive current transformer.Under the background that country greatly develops extra-high voltage and intelligent grid, optical fiber current mutual inductor is as the significant assembly application on a small scale of intelligent grid, by the restriction of the factors such as light path noise and digital quantization noise, small current measurement precision and stability thereof are difficult to meet metrology applications demand, become and limit its major technology bottleneck at metering field application.
The mainstream technology scheme of optical fiber current mutual inductor adopts Sagnac interferometer and digital closed loop detection technique.According to the difference of institute's use phase-modulator in light path, the specific implementation of Sagnac interferometer has the following two kinds
(1) based on the implementation of straight waveguide phase modulator: as shown in Figure 1, the light that light source 10 sends is transferred to the polarizer 12 through circulator 11, the linearly polarized light that the polarizer 12 exports is through first 45 ° of fusing point, be divided into the orthogonal linearly polarized light of two bundles protects off-delay fiber optic loop 14 fast and slow axis transmission along straight waveguide phase modulator 13 input, after protecting off-delay fiber optic loop 14, the orthogonal circularly polarized light of two bundles is become from second 45 ° of fusing point, second 45 ° of fusing point is returned after catoptron 15 reflects, again the linearly polarized light that two bundles are orthogonal is become, after first 45 ° of fusing point, two bundle orhtogonal linear polarizaiton light interfere at the component of the polarizer 12 optical direction, generate interference signal, photodetector 16 detects interference signal and sends to signal processing unit 17, interference signal only carries faraday's phase shift that tested electric current produces.
The advantage of the program is that light channel structure has good reciprocity, have good immunity, but there are the following problems to the environmental interference such as temperature, vibration:
A) optical path loss is large, requires that the transimpedance of light source output power and photodetector is enough large, could meeting the requirement of mutual inductor output signal-to-noise ratio, because this increasing light path noise, affecting the small current measurement precision of mutual inductor;
B) production technology of straight wave guide is immature, and cannot monitoring shaft angle degree of waveguide chip and input and output tail optical fiber, the polarization error introduced thus causes mutual inductor output offset larger.
(2) based on the implementation of Y waveguide phase-modulator: use for reference fiber-optics gyroscope, ABB AB proposes the implementation based on Y waveguide phase-modulator, as shown in Figure 2.The measuring principle of the program is identical with the straight wave guide scheme shown in Fig. 1, difference is: adopt Y waveguide phase-modulator 21 to complete the function of the polarizer 12, first 45 ° of fusing point and straight waveguide phase modulator 13 3 devices, and by realizing the orthogonal of two linearly polarized lights with 90 ° of fusing points of coupling mechanism 22 tail optical fiber, two orthogonal linearly polarized lights realize closing light at the output terminal of coupling mechanism 22.
The technical advantage of this light path scheme is:
A) Y waveguide is integrated with the function of the polarizer and phase-modulator, greatly reduces optical path loss, reduces light path noise, can improve the small current measurement precision of mutual inductor;
B) Y waveguide mature production technology, greatly reduces the output offset of mutual inductor.
But also there are the following problems for the program:
A) comparatively straight wave guide scheme is poor for light path reciprocity, to vibration and rotation effect sensitivity.Reason is: the Y waveguide loop that Y waveguide phase-modulator and coupling mechanism input tail optical fiber are formed, and can be equivalent to M-Z interferometer or Sagnac interferometer, to vibration and rotation effect sensitivity, affect the stability of mutual inductor measuring accuracy of measurement.
B) impact of polarization error on mutual inductor measuring accuracy of measurement of Y waveguide loop is larger.
At present, the research of optical fiber current mutual inductor Y waveguide loop polarization characteristic and suppression technology thereof is not yet had.
Summary of the invention
The essence improving optical fiber current mutual inductor small current measurement precision reduces system noise, improves the output signal-to-noise ratio of mutual inductor.The purpose of this utility model is to reduce light path noise to improve small current measurement precision and stability thereof, proposing a kind of polarization error restraining device of Y waveguide loop of optical fiber current mutual inductor.
The polarization error restraining device of the Y waveguide loop of the optical fiber current mutual inductor that the utility model provides, comprises Y waveguide phase-modulator and polarization beam apparatus.Two output tail optical fibers of Y waveguide phase-modulator input tail optical fiber with fusing point 2 with two of polarization beam apparatus respectively by fusing point 1 and are connected, two tail optical fibers that two tail optical fibers connected by fusing point 1 are connected with by fusing point 2 form the two-arm of Y waveguide loop respectively, and the arm length difference of Y waveguide loop two-arm is △ L.The input tail optical fiber of Y waveguide phase-modulator is connected with circulator, and the output tail optical fiber of polarization beam apparatus is connected with guarantor's off-delay fiber optic loop.Described fusing point 1 is determined according to the working method of polarization beam apparatus, if polarization beam apparatus select fast axle lead to light wait a moment axle cut-off working method, fusing point 1 is 0 °, otherwise fusing point 1 is 90 °; Described fusing point 2 is 90 °.
Advantage of the present utility model and good effect are: (1) can reduce optical path loss further, reduce the shot noise of detector, improve the small current measurement precision of mutual inductor; (2) by suppressing the polarization error of Y waveguide loop, can further improve the stability of small current measurement precision.
Accompanying drawing explanation
Fig. 1 is the optical fiber current mutual inductor light path schematic diagram based on straight waveguide phase modulator;
Fig. 2 is the optical fiber current mutual inductor light path schematic diagram based on Y waveguide phase-modulator;
Fig. 3 is the schematic diagram of the polarization error restraining device of Y waveguide loop of the present utility model;
Fig. 4 is the schematic diagram of the optical fiber current mutual inductor of the polarization error restraining device using Y waveguide loop of the present utility model.
Embodiment
Below in conjunction with drawings and Examples, the technical solution of the utility model is described in further detail.
The utility model adopts the combination of Y waveguide phase-modulator and polarization beam apparatus to replace the combination of Y waveguide phase-modulator in Fig. 2 and coupling mechanism, by the two-arm arm length difference of asymmetric coupling Y waveguide loop, as novel light path design, the polarization error that the program can effectively suppress waveguide loop to be introduced.
The utility model provides a kind of polarization error restraining device of Y waveguide loop of optical fiber current mutual inductor, as shown in Figure 3, comprise Y waveguide phase-modulator 21 and polarization beam apparatus 31, two output tail optical fibers of Y waveguide phase-modulator 21 input tail optical fiber with fusing point 2 with two of polarization beam apparatus 31 by fusing point 1 and are connected, two tail optical fibers that two tail optical fibers connected by fusing point 1 are connected with by fusing point 2 form the two-arm of Y waveguide loop respectively, Y waveguide loop two-arm Length discrepancy, arm length difference is △ L.The Y waveguide loop that the utility model proposes is made up of the fusing point of Y waveguide phase-modulator 21 and polarization beam apparatus 31 and two device tail optical fibers thereof, in the light path of optical fiber current mutual inductor, Y waveguide loop respectively with 2 ports of circulator 11 with protect off-delay fiber optic loop 14 and be connected, wherein, the input tail optical fiber of Y waveguide phase-modulator 21 is connected with 2 ports of circulator 11, and the output tail optical fiber of polarization beam apparatus 31 is connected with guarantor's off-delay fiber optic loop 14.
Wherein: fusing point 2 is 90 °; Fusing point 1 is determined according to the working method of polarization beam apparatus 31.To wait a moment the working method of axle cut-off if polarization beam apparatus 31 selects fast axle to lead to light, then fusing point 1 is 0 °, otherwise if polarization beam apparatus selects slow axis to lead to light and the working method of fast axle cut-off, then fusing point 1 is 90 °.
As shown in Figure 4, the polarization error restraining device of the Y waveguide loop provided by the utility model is used for optical fiber current mutual inductor, the light that light source 10 sends is transferred to the polarization error restraining device of Y waveguide loop of the present utility model through circulator 11, Y waveguide phase-modulator 21 exports the orthogonal linearly polarized light of two bundles, again through polarization beam apparatus 31, the fast and slow axis transmission of the linearly polarized light input guarantor off-delay fiber optic loop 14 that two bundles are orthogonal, after protecting off-delay fiber optic loop 14, become the orthogonal circularly polarized light of two bundles from 45 ° of fusing points, the fusing point 3 in Fig. 4 is 45 °.Fusing point 3 is returned after catoptron 15 reflects, again the linearly polarized light that two bundles are orthogonal is become, again through polarization beam apparatus 31 and Y waveguide phase-modulator 21, two bundle orhtogonal linear polarizaiton light interfere at the component of Y waveguide phase-modulator 21 optical direction, generate interference signal, photodetector 16 detects interference signal and sends to signal processing unit 17.
By the polarization error that the arm length difference of asymmetric coupling Y waveguide loop two-arm suppresses waveguide loop to be introduced in the utility model, the arm length difference △ L of Y waveguide loop is specifically depending on the coherence of light source and the decoherence length of light path.
The Y waveguide loop of optical fiber current mutual inductor of the present utility model comprises Y waveguide phase-modulator and polarization beam apparatus, due to any optical device polarization characteristic and non-fully is desirable, and light path manufacture craft can not ensure that the coupling angle of Y waveguide phase-modulator and polarization beam apparatus tail optical fiber is desirable 45 °, above-mentioned nonideal characteristic causes there is some polarization coupled point in waveguide loop, thus causes the polarization coupled component producing multiple parasitism in light path.Theoretical and simulation analysis shows, in the process changing waveguide loop arm length difference, the optical path difference wherein between some distributed polarization coupling component is compensated and reconstructs its coherence, thus occurs error extreme value.When the arm length difference of waveguide loop continues to increase, make optical path difference between any distributed polarization coupling component all much larger than the coherent length of light source, thus not there is coherence, therefore can not produce polarization and cause measuring error, Here it is suppresses the effective ways of polarization error when waveguide loop optical device polarization characteristic does not meet the demands.
Verify by experiment, after application the utility model device, can significantly improve small current measurement precision and the stability thereof of optical fiber current mutual inductor, specific targets are, the precision of the optical fiber current mutual inductor after application the utility model reaches IEC 0.2S when rated current is 600A ~ 1200A.
Claims (1)
1. a polarization error restraining device for the Y waveguide loop of optical fiber current mutual inductor, is characterized in that, comprises Y waveguide phase-modulator and polarization beam apparatus; Two output tail optical fibers of described Y waveguide phase-modulator input tail optical fiber with fusing point 2 with two of polarization beam apparatus respectively by fusing point 1 and are connected, two tail optical fibers that two tail optical fibers connected by fusing point 1 are connected with by fusing point 2 form the two-arm of Y waveguide loop respectively, and the arm length difference of Y waveguide loop two-arm is △ L; The input tail optical fiber of Y waveguide phase-modulator is connected with circulator, and the output tail optical fiber of polarization beam apparatus is connected with guarantor's off-delay fiber optic loop;
Described fusing point 1 is determined according to the working method of polarization beam apparatus, if polarization beam apparatus select fast axle lead to light wait a moment axle cut-off working method, fusing point 1 is 0 °, otherwise fusing point 1 is 90 °; Described fusing point 2 is 90 °.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201520015690.8U CN204330856U (en) | 2015-01-09 | 2015-01-09 | The polarization error restraining device of the Y waveguide loop of optical fiber current mutual inductor |
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| CN201520015690.8U CN204330856U (en) | 2015-01-09 | 2015-01-09 | The polarization error restraining device of the Y waveguide loop of optical fiber current mutual inductor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104535819A (en) * | 2015-01-09 | 2015-04-22 | 胡雨亭 | Polarization error restraining device and method for Y waveguide loop of optical current transformer |
| CN107727911A (en) * | 2017-11-15 | 2018-02-23 | 中国电力科学研究院有限公司 | A kind of optical fiber current mutual inductor device and its current measuring method |
| CN108534798A (en) * | 2018-02-27 | 2018-09-14 | 北京大学 | A kind of nonreciprocal error cancelling method of polarization in dual-polarization optical fibre gyro and dual-polarization optical fibre gyro |
-
2015
- 2015-01-09 CN CN201520015690.8U patent/CN204330856U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104535819A (en) * | 2015-01-09 | 2015-04-22 | 胡雨亭 | Polarization error restraining device and method for Y waveguide loop of optical current transformer |
| CN104535819B (en) * | 2015-01-09 | 2018-06-01 | 胡雨亭 | The polarization error restraining device and method of the Y waveguide loop of optical fiber current mutual inductor |
| CN107727911A (en) * | 2017-11-15 | 2018-02-23 | 中国电力科学研究院有限公司 | A kind of optical fiber current mutual inductor device and its current measuring method |
| CN108534798A (en) * | 2018-02-27 | 2018-09-14 | 北京大学 | A kind of nonreciprocal error cancelling method of polarization in dual-polarization optical fibre gyro and dual-polarization optical fibre gyro |
| CN108534798B (en) * | 2018-02-27 | 2022-05-03 | 北京大学 | Polarization nonreciprocal error elimination method in dual-polarization fiber-optic gyroscope and dual-polarization fiber-optic gyroscope |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150513 Termination date: 20180109 |