CN113419341B - Method and device for reconstructing optical field of optical fiber interferometer in complex manner - Google Patents

Method and device for reconstructing optical field of optical fiber interferometer in complex manner Download PDF

Info

Publication number
CN113419341B
CN113419341B CN202110688836.5A CN202110688836A CN113419341B CN 113419341 B CN113419341 B CN 113419341B CN 202110688836 A CN202110688836 A CN 202110688836A CN 113419341 B CN113419341 B CN 113419341B
Authority
CN
China
Prior art keywords
signal
optical
interference
complex
pulse signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110688836.5A
Other languages
Chinese (zh)
Other versions
CN113419341A (en
Inventor
马丽娜
陈祥国
尚凡
戚悦
陈羽
王俊
熊水东
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
National University of Defense Technology
Original Assignee
National University of Defense Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by National University of Defense Technology filed Critical National University of Defense Technology
Priority to CN202110688836.5A priority Critical patent/CN113419341B/en
Publication of CN113419341A publication Critical patent/CN113419341A/en
Application granted granted Critical
Publication of CN113419341B publication Critical patent/CN113419341B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines

Abstract

The invention relates to the field of optics, and relates to the technical contents of optical fiber interferometer signal demodulation, optical field conversion, signal crosstalk, polarization suppression and the like, in particular to a method and a device for reconstructing a complex number of an optical fiber interferometer optical field, wherein the method comprises the following steps: s1: judging the form of the inquiry pulse signal; s2: confirming an interference signal sampling mode according to the inquiry pulse signal form; and S3, interference light field complex reconstruction. The invention can accurately reconstruct the interference signal of the optical fiber optical interferometer actually acquired by the photoelectric detector into a complex expression form, and the complex expression form of the interference signal can be more conveniently and efficiently applied to the basic operation process of the signal, and is a necessary signal processing link for realizing the technologies such as polarization synthesis, crosstalk inhibition and the like.

Description

Method and device for reconstructing optical field of optical fiber interferometer in complex manner
Technical Field
The invention relates to the field of optics, relates to the technical contents of signal demodulation, light field conversion, signal crosstalk, polarization suppression and the like of an optical fiber interferometer, and particularly relates to a method and a device for reconstructing a complex number of an optical fiber interferometer light field.
Background
The optical fiber interferometer has important application in the fields of optical fiber gyroscopes, optical fiber underwater sound detection, seismic wave detection and the like. The optical coherent detection mode is adopted, so that the optical fiber sensing system has the outstanding advantages of high sensitivity, large dynamic range and the like, and is widely applied to the civil and military fields by combining the inherent advantages of small volume, light weight, electromagnetic interference resistance and the like of the optical fiber sensing system. However, since the sensitivity of the fiber interferometer is high, a lot of environmental disturbances, optical path crosstalk and the like affect the phase, and it is one of the basic technologies to remove the influence of disturbance factors by various signal processing means, and the signal processing technology is generally complex.
In many interference signal processing processes, it is often necessary to perform multiplication and division operations on a plurality of interference results to achieve the purpose of phase information cancellation or phase information growth. The documents "Reduction of crosstalk in interferometric sensor arrays using inversion profiling" (proc. SPIE,2008, vol.704, paper 70044Z) and the patent "Method and apparatus for applying crosstalk of crosstalk and noise in time-division multiplexed interferometric sensor systems (patent No. US 7466422B 2)" report an inversion stripping algorithm that requires subtraction of two interference signals to eliminate crosstalk between different interference channels. The document "Low-Cross and Polarization-Independent multiline interference Fiber Array Based on Fiber Bragg gratings" (. J.Lightw.Technol.34 (2016) 4232-4239) reports a Polarization synthesis algorithm that requires multiplication and subtraction of four interference signals to eliminate Polarization-affecting factors between different interference channels. In practice, the interference result of the fiber interferometer is obtained as a real number expression result after conversion by the photoelectric detector, and can be written as (formula 1)
Figure GDA0003787999690000011
I (t) represents the light intensity output by the interferometer, A represents the DC component, B represents the AC component amplitude, re represents the operation taking the real part of the complex number,
Figure GDA0003787999690000012
a signal term representing the interferometer is used to,
Figure GDA0003787999690000013
is the noise of the interferometer. When the addition, subtraction, multiplication and division operation of the interference light field is involved, an unnecessary frequency term appears when the (formula 1) is directly adopted for calculation. For two interference signals I 1 (t) and I 2 (t)
Figure GDA0003787999690000014
Figure GDA0003787999690000015
Obtaining sum or difference terms of interference signals, i.e. obtaining
Figure GDA0003787999690000016
Or
Figure GDA0003787999690000017
But in actual operation, directly connecting I 1 (t) and I 2 (t) when addition, subtraction, multiplication, and division are performed, an extra phase term is generated in any case, and the phase term and the desired phase term are often not separated. For example, performing a mixing multiplication yields:
Figure GDA0003787999690000021
it can be easily deduced that adding, subtracting and dividing will all be a coupled result of a plurality of frequency terms. A simple way to do this is to obtain a complex representation of the interference field, i.e.
Figure GDA0003787999690000022
Figure GDA0003787999690000023
The complex expression forms of the two interference light fields are directly subjected to multiplication and division operation to obtain
Figure GDA0003787999690000024
And
Figure GDA0003787999690000025
then the real part is calculated to obtain
Figure GDA0003787999690000026
And
Figure GDA0003787999690000027
the complex expression form of the visible interference light field is a simplified algorithm and an improved meter in many applicationsThe key of calculation efficiency is that complex processing of the complex signals of the optical fiber interferometer is often simplified and even becomes the basis for ensuring the correctness of the algorithm.
Due to the complexity of the interference light field, signals are often loaded in a phase term of a cosine function, phase shift of frequency spectrum components is brought by directly obtaining a sine term from the cosine term through mathematical transformation, and special design is needed for the complex reconstruction of the interference light field according to the signal characteristics of the interference light field.
Disclosure of Invention
The invention aims to provide a method and a device for reconstructing the complex number of an optical fiber interferometer optical field.
In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:
a method for reconstructing a complex number of an optical field of an optical fiber interferometer comprises the following steps:
s1: determination of query pulse signal form: if the query pulse signal is a pair of signals with a fixed frequency difference f m The pulse of (3) is judged as a heterodyne modulation signal; if the inquiry pulse is three adjacent pulse pairs with the phase difference of 120 degrees, the inquiry pulse is judged to be a 3 multiplied by 3 modulation signal;
s2: confirming an interference signal sampling mode according to the inquiry pulse signal form: when the interrogation pulse signal is heterodyne modulation signal, a group of interference results is collected, defined as I H (t); when the inquiry pulse signal is a 3 multiplied by 3 modulation signal, three groups of interference results are collected and are respectively marked as I 1 (t)、I 2 (t) and I 3 (t)；
S3, interference light field complex reconstruction:
s3.1 set of interference results I for S2 acquisition H (t), the following steps are taken:
s3.1.1 general formula I H (t) is each independently related to cos (2 π f) m t)、sin(2πf m t) mixing to obtain two expressions I C And I S Namely:
Figure GDA0003787999690000028
s3.1.2 general formula I C And I S Low-pass filtering is respectively carried out, and the retention is less than f m Obtaining the spectral components of expression I C_low And I S_low ：
Figure GDA0003787999690000031
Figure GDA0003787999690000032
Wherein B represents the amplitude of the alternating current quantity,
Figure GDA0003787999690000033
a signal term representing the interferometer is used to,
Figure GDA0003787999690000034
is the noise of the interferometer;
s3.1.3 Generation of phase term complex optical field expression form I com ：
Figure GDA0003787999690000035
S3.2 three groups of interference results I for S2 acquisition 1 (t)、I 2 (t) and I 3 (t) the following steps are taken:
s3.2.1 general formula I 1 (t)、I 2 (t) and I 3 (t) adding and averaging to obtain a direct current term:
A＝{I 1 (t)+I 2 (t)+I 3 (t)}/3
s3.2.2 general formula I 1 (t)、I 2 (t) and I 3 (t) subtracting the direct current terms respectively to obtain three alternating current terms,namely:
Figure GDA0003787999690000036
Figure GDA0003787999690000037
Figure GDA0003787999690000038
s3.2.3 will
Figure GDA0003787999690000039
Minus
Figure GDA00037879996900000310
Obtaining a sine term:
Figure GDA00037879996900000311
s3.2.4 Synthesis of Complex representation form I of interferometric results containing phase term of interferometer com ：
Figure GDA00037879996900000312
Preferably, the interrogation pulse signal, which contains the heterodyne modulation signal, is generated by means of optical frequency shift.
Preferably, the interrogation pulse signal, which contains a heterodyne modulation signal, is generated by modulating the light source frequency using a triangular wave.
Preferably, for a query pulse signal containing a 3 × 3 modulated signal, the three sets of phase differences are
Figure GDA00037879996900000313
0 and
Figure GDA00037879996900000314
is generated.
Preferably, the interrogation pulse signal, which contains a 3 × 3 modulation signal, is generated by a 3 × 3 coupler.
The invention also provides a device for reconstructing the complex number of the optical fiber interferometer optical field based on the method, which comprises a modulation signal loading module 1 and a signal processing module 2;
the modulation signal loading module 1 is used for generating a pulse sequence of an interrogation interferometer and injecting the pulse sequence into the optical fiber interferometer, and comprises an interrogation pulse module 101 and an optical fiber interferometer 102, wherein the interrogation pulse module 101 is used for generating the pulse sequence of the interrogation interferometer and injecting the pulse sequence into the optical fiber interferometer 102, the optical fiber interferometer 102 is used for generating an interference optical field and comprises a coupler 102A and Faraday rotators 102B and 102C, and the interrogation pulse module 101 is connected to an input port 102A1 of the optical fiber interferometer 102 through an optical fiber;
the signal processing module 2 is used for performing photoelectric conversion on an interference light field generated by the optical fiber interferometer 102 and then performing complex reconstruction processing, and comprises a photoelectric conversion module 201, an acquisition module 202 and a PC 203; the photoelectric conversion module 201 is used for photoelectric conversion, the acquisition module 202 is used for sampling an electric signal after photoelectric conversion, and the PC 203 is used for storing, displaying and performing complex reconstruction on the sampled signal; the photoelectric conversion module 201 is connected to an acquisition module 202 through a cable, and the acquisition module 202 is connected to the PC 203 through a signal line.
The signal loading module 1 and the signal processing module 2 are connected by an optical fiber, and the connection mode is that the output port 102A2 of the optical fiber interferometer 102 is connected to the photoelectric conversion module 201.
The invention has the following beneficial effects: the invention can accurately reconstruct the interference signal of the optical fiber optical interferometer actually acquired by the photoelectric detector into a complex expression form, and the complex expression form of the interference signal can be more conveniently and efficiently applied to the basic operation process of the signal, and is a necessary signal processing link for realizing the technologies such as polarization synthesis, crosstalk inhibition and the like.
Drawings
FIG. 1 is a flow chart of a method for the complex reconstruction of an optical field of an optical fiber interferometer according to the present invention;
FIG. 2 is a structural diagram of the optical fiber interferometer light field complex reconstruction device of the present invention.
Detailed Description
The present invention is further described with reference to the accompanying drawings, and as shown in fig. 1, the method for performing the complex reconstruction of the optical fiber interferometer optical field according to the present invention includes the following steps for performing different processing on the optical fiber interferometer optical fields of two different modulation methods:
s1: determining interrogation pulse signal form
If the query pulse signal is a pair of signals with a fixed frequency difference f m The pulse of (3) is judged as a heterodyne modulation signal; if the inquiry pulse is three adjacent pulses with the phase difference of 120 degrees, the inquiry pulse is judged to be a 3 multiplied by 3 modulation signal;
s2: confirming an interference signal sampling mode according to the inquiry pulse signal form: when the interrogation pulse signal is a heterodyne modulation signal, a set of interference results, defined as I, is collected H (t), can be expressed as
Figure GDA0003787999690000041
I H (t) represents the light intensity output by the interferometer after heterodyne modulation, A represents the DC component, B represents the AC component amplitude, re represents the operation of taking the real part of a complex number, 2 pi f m t is the heterodyne modulation term, where f m In order to modulate the frequency of the signal,
Figure GDA0003787999690000042
a signal term representing the interferometer is used to,
Figure GDA0003787999690000043
is the noise of the interferometer.
When the inquiry pulse signal is 3 multiplied by 3 modulation signal, three groups of interference results are collected and respectively marked as I 1 (t)、I 2 (t) and I 3 (t) can be shownIs up to
Figure GDA0003787999690000044
Figure GDA0003787999690000045
Figure GDA0003787999690000046
I 1 (t)、I 2 (t) and I 3 (t) represents the light intensity output by the 3X 3 modulation interferometer, A represents the DC component, B represents the amplitude of the AC component, re represents the operation of taking the real part of the complex number,
Figure GDA0003787999690000047
a signal term representing the interferometer is used to,
Figure GDA0003787999690000048
is the noise of the interferometer.
Figure GDA0003787999690000049
Is the phase of the interferometer itself, I 1 (t)、I 2 (t) and I 3 (t) are respectively superposed by 3 x 3 modulation
Figure GDA00037879996900000410
0 and
Figure GDA00037879996900000411
phase.
S3, interference light field complex reconstruction:
s3.1 set of interference results I for S2 acquisition H (t), the following steps are taken:
s3.1.1 modulation term 2 pi f due to heterodyne m t is human as an introduction item, I H (t) is each independently related to cos (2 π f) m t)、sin(2πf m t) mixing to obtain two expressions I C And I S Wherein:
Figure GDA0003787999690000051
Figure GDA0003787999690000052
s3.2.2 general formula I C And I S Low-pass filtering respectively, keeping less than f m Obtaining the spectral components of:
Figure GDA0003787999690000053
Figure GDA0003787999690000054
s3.3.3 Complex expression form of synthetic interference result
Figure GDA0003787999690000055
Figure GDA0003787999690000056
S3.2 three groups of interference results I for S2 acquisition 1 (t)、I 2 (t) and I 3 (t) the following steps are taken:
s3.2.1 general formula I 1 (t)、I 2 (t) and I 3 (t) adding to obtain a DC term
Figure GDA0003787999690000057
Thus is provided with
A＝{I 1 (t)+I 2 (t)+I 3 (t)}/3
S3.2.2 general reaction of I 1 (t)、I 2 (t) and I 3 (t) subtracting the direct current terms respectively to obtain three alternating current terms, namely:
Figure GDA0003787999690000058
Figure GDA0003787999690000059
Figure GDA00037879996900000510
s3.2.3 will
Figure GDA00037879996900000511
Minus one (C) of
Figure GDA00037879996900000512
Obtaining a sine term:
Figure GDA0003787999690000061
s3.2.4 Complex expression form I of synthetic interference result com
Figure GDA0003787999690000062
It can be seen that the complex expression form of the interference signal light field, that is, the complex light field of the interference signal, can be obtained by adopting the method for synthesizing the interference light complex light field of the invention, and a signal basis is provided for polarization control, multi-channel crosstalk inhibition and the like.

Claims (5)

1. A method for reconstructing a plurality of optical fiber interferometer optical fields is characterized by comprising the following steps:
s1: determination of query pulse signal form: if the inquiry pulse signal is a pair containing a fixed frequency difference f m Is determined to be heterodyneModulating the signal; if the inquiry pulse is three adjacent pulse pairs with the phase difference of 120 degrees, the inquiry pulse is judged to be a 3 multiplied by 3 modulation signal;
s2: confirming an interference signal sampling mode according to the inquiry pulse signal form: when the interrogation pulse signal is a heterodyne modulation signal, a set of interference results, defined as I, is collected H (t); when the inquiry pulse signal is 3 multiplied by 3 modulation signal, three groups of interference results are collected and respectively marked as I 1 (t)、I 2 (t) and I 3 (t)；
S3, interference light field complex reconstruction:
s3.1 set of interference results I for S2 acquisition H (t), the following steps are taken:
s3.1.1 general formula I H (t) is each independently related to cos (2 π f) m t)、sin(2πf m t) mixing to obtain two expressions I C And I S Namely:
I C ＝I H (t)×cos(2πf m t)
I S ＝I H (t)×sin(2πf m t)；
s3.1.2 general formula I C And I S Low-pass filtering is respectively carried out, and the retention is less than f m Obtaining the spectral components of expression I C_low And I S_low ：
Figure FDA0003787999680000011
Figure FDA0003787999680000012
Wherein, B represents the amplitude of the alternating current quantity,
Figure FDA0003787999680000013
a signal term representing the interferometer is used to,
Figure FDA0003787999680000014
is the noise of the interferometer;
s3.1.3 Generation of phase term complex optical field expression form I com ：
Figure FDA0003787999680000015
S3.2 three groups of interference results I for S2 acquisition 1 (t)、I 2 (t) and I 3 (t) the following steps are taken:
s3.2.1 general formula I 1 (t)、I 2 (t) and I 3 (t) adding and averaging to obtain a direct current term:
A＝{I 1 (t)+I 2 (t)+I 3 (t)}/3
s3.2.2 general formula I 1 (t)、I 2 (t) and I 3 (t) subtracting the direct current terms respectively to obtain three alternating current terms, namely:
Figure FDA0003787999680000016
Figure FDA0003787999680000017
Figure FDA0003787999680000018
s3.2.3 will
Figure FDA0003787999680000019
Minus
Figure FDA00037879996800000110
Obtaining a sine term:
Figure FDA00037879996800000111
s3.2.4 Synthesis of interferometerComplex representation of interference results of phase terms I com ：
Figure FDA00037879996800000112
2. A method for the complex reconstruction of the optical field of the fiber interferometer according to claim 1, characterized in that: the interrogation pulse signal containing heterodyne modulation signal is generated by optical frequency shift.
3. A method for the complex reconstruction of the optical field of a fiber interferometer according to claim 2, characterized in that: for an interrogation pulse signal containing a heterodyne modulation signal, it is generated by two optical frequency shifters.
4. A method for the complex reconstruction of the optical field of the fiber interferometer according to claim 1, characterized in that: for a query pulse signal containing a 3 x 3 modulated signal, the three groups of phase differences are respectively
Figure FDA0003787999680000021
0 and
Figure FDA0003787999680000022
is generated.
5. A method for the complex reconstruction of the optical field of the fiber interferometer according to claim 4, characterized in that: for a query pulse signal containing a 3 x 3 modulated signal, it is generated by a 3 x 3 coupler.
CN202110688836.5A 2021-06-22 2021-06-22 Method and device for reconstructing optical field of optical fiber interferometer in complex manner Active CN113419341B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110688836.5A CN113419341B (en) 2021-06-22 2021-06-22 Method and device for reconstructing optical field of optical fiber interferometer in complex manner

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110688836.5A CN113419341B (en) 2021-06-22 2021-06-22 Method and device for reconstructing optical field of optical fiber interferometer in complex manner

Publications (2)

Publication Number Publication Date
CN113419341A CN113419341A (en) 2021-09-21
CN113419341B true CN113419341B (en) 2022-11-18

Family

ID=77789693

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110688836.5A Active CN113419341B (en) 2021-06-22 2021-06-22 Method and device for reconstructing optical field of optical fiber interferometer in complex manner

Country Status (1)

Country Link
CN (1) CN113419341B (en)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1752836A (en) * 2005-09-27 2006-03-29 北京理工大学 Demodulation method of optical fiber interference signal
CN101718563A (en) * 2009-12-09 2010-06-02 北京理工大学 Phase-shift white light interferometry method based on 3*3 optical fiber coupler
CN102353393B (en) * 2011-07-01 2014-08-20 浙江大学 Quadrature demodulation device for interference type photo-sensor based on pi/2 phase modulation
CN102322880B (en) * 2011-08-18 2013-06-05 天津大学 Polarization sensitive distributive optical frequency domain reflection disturbance sensor and demodulation method
CN104932112B (en) * 2015-06-26 2017-10-20 中国科学院上海光学精密机械研究所 A kind of real-time light field reconfigured geometry and reconstructing method
CN106643813A (en) * 2016-10-14 2017-05-10 中国人民解放军国防科学技术大学 Method for synthesizing phase generated carrier modulation signal-contained interference light complex-number optical field
CN108020314B (en) * 2016-11-01 2019-09-13 北京大学 Scale Fiber-Optic Hydrophone Array system and acceleration transducer array system and measurement method
CN106679790B (en) * 2016-12-05 2023-04-21 华南理工大学 Cross-correlation demodulation method for improving sensitivity of distributed optical fiber vibration sensing

Also Published As

Publication number Publication date
CN113419341A (en) 2021-09-21

Similar Documents

Publication Publication Date Title
CN103954310B (en) A kind of large Dynamic Signal demodulating equipment and demodulation method of interferometric optical fiber sensor
Chen et al. High-fidelity distributed fiber-optic acoustic sensor with fading noise suppressed and sub-meter spatial resolution
Plotnikov et al. Dynamic range analysis of the phase generated carrier demodulation technique
US20090111417A1 (en) Adaptive mixing for high slew rates
Paitz et al. Rotation and strain ambient noise interferometry
Liu et al. Quantitative demodulation of distributed low-frequency vibration based on phase-shifted dual-pulse phase-sensitive OTDR with direct detection
CN101686087B (en) Wavelength demodulation system and method based on two outputs of a 3 x 3 coupler
Hou et al. Large dynamic range and high sensitivity PGC demodulation technique for tri-component fiber optic seismometer
Cameron et al. A symmetric analogue demodulator for optical fiber interferometric sensors
CN106323478A (en) Phase generation and carrier modulation and demodulation system of optical fiber interferometric sensor with polarization fading resistance
Chen et al. Denoising of distributed acoustic sensing seismic data using an integrated framework
CN110987373B (en) Method and device for measuring phase modulation depth of interference type optical fiber sensor
Chen et al. Denoising method of the Φ-OTDR system based on EMD-PCC
Sun et al. High accuracy and real-time positioning using MODWT for long range asymmetric interferometer vibration sensors
Song et al. An efficient wavefield inversion for transversely isotropic media with a vertical axis of symmetry
CN113419341B (en) Method and device for reconstructing optical field of optical fiber interferometer in complex manner
US6363034B1 (en) Methods and apparatus for phase angle demodulation
Li et al. Denoising method based upon ECEMD and selective addition for phi-OTDR
Baziw et al. Principle phase decomposition: A new concept in blind seismic deconvolution
CN106643813A (en) Method for synthesizing phase generated carrier modulation signal-contained interference light complex-number optical field
Faggioni The information protection in automatic reconstruction of not continuous geophysical data series
Zhang et al. Investigation on the maximum signal handling capability of fiber optic interferometric sensor based on the digital heterodyne demodulation scheme
Zhang et al. Denoising using 3× 3 coupler demodulation
CN113219525A (en) Offset imaging defuzzification method and device
CA2843156C (en) Sensor data carrying capability of phase generated carriers

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant