CN109556756B - Temperature sensor based on vernier effect of multi-wavelength fiber laser - Google Patents

Temperature sensor based on vernier effect of multi-wavelength fiber laser Download PDF

Info

Publication number
CN109556756B
CN109556756B CN201811609127.8A CN201811609127A CN109556756B CN 109556756 B CN109556756 B CN 109556756B CN 201811609127 A CN201811609127 A CN 201811609127A CN 109556756 B CN109556756 B CN 109556756B
Authority
CN
China
Prior art keywords
wavelength
optical fiber
filter
fiber
laser
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
CN201811609127.8A
Other languages
Chinese (zh)
Other versions
CN109556756A (en
Inventor
周雪芳
周豫
刘柯
毕美华
杨国伟
胡淼
李齐良
卢旸
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.)
Hangzhou Dianzi University
Original Assignee
Hangzhou Dianzi University
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 Hangzhou Dianzi University filed Critical Hangzhou Dianzi University
Priority to CN201811609127.8A priority Critical patent/CN109556756B/en
Publication of CN109556756A publication Critical patent/CN109556756A/en
Application granted granted Critical
Publication of CN109556756B publication Critical patent/CN109556756B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
    • G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres

Abstract

The invention belongs to the technical field of optical fiber sensing, and particularly relates to a temperature sensor based on vernier effect of a multi-wavelength optical fiber laser, which comprises the following components: the device comprises a pumping light source, a wavelength division multiplexer, an erbium-doped optical fiber, an optical fiber FP filter, an optical fiber Sagnac filter and a spectrometer which are sequentially arranged along the direction of a light path, wherein pumping light output by the pumping light source outputs wide-spectrum laser after passing through the wavelength division multiplexer and the erbium-doped optical fiber, the wide-spectrum laser enters the optical fiber FP filter to form multi-wavelength laser, the multi-wavelength laser outputs multi-wavelength optical fiber laser signals with envelopes based on vernier effect in the optical fiber Sagnac filter, and the multi-wavelength optical fiber laser signals are input into the spectrometer for measurement. According to the temperature sensor, the erbium-doped optical fiber is used as a gain medium, the optical fiber Sagnac filter and the FP filter are in mixed cascade connection to control multi-wavelength output, and compared with the existing single-filter multi-wavelength optical fiber laser sensor, the temperature sensor is higher in temperature sensitivity.

Description

Temperature sensor based on vernier effect of multi-wavelength fiber laser
Technical Field
The invention belongs to the technical field of optical fiber sensing, and particularly relates to a temperature sensor based on vernier effect of a multi-wavelength optical fiber laser.
Background
The optical fiber sensing technology is a novel sensing technology which is developed along with the development of the optical fiber technology and the optical fiber communication technology in the 70 s of the 20 th century; the optical fiber sensing and detecting device senses and detects an external detected signal by taking optical waves as a sensing signal and optical fibers as a transmission medium, and is greatly different from the traditional electrical sensor in the aspects of sensing mode, sensing principle, signal detection and processing and the like. The optical fiber has the advantages of no electricity, small volume, small mass, easy bending, electromagnetic interference resistance and good radiation resistance, and is particularly suitable for being used in the severe environments of flammability and explosiveness, strict limitation of space, strong electromagnetic interference and the like. Therefore, once the optical fiber sensing technology is available, great attention is paid to the optical fiber sensing technology, and the optical fiber sensing technology is researched and applied to various important fields.
The multi-wavelength fiber laser (MWFL) has the advantages of simple structure, good compatibility with an optical fiber system, corrosion resistance, electromagnetic interference resistance, high reaction sensitivity and the like. Therefore, MWFL is widely used in the fields of modern optical communication, photoelectric detection and sensing, structure embedded monitoring, aerospace, etc. In MWFL, the fiber interferometer is usually used as a comb filter unit of the system, and in addition, the fiber interferometer can also be used as a sensor to detect some parameters, such as temperature, pressure, ultrasound, tension, refractive index, humidity, gas concentration, and the like. The sensitivity is an important index for representing the performance of the sensor, so that the improvement of the sensitivity of the sensor has important practical significance.
However, the conventional multi-wavelength laser temperature sensor has the disadvantages of high cost, complex structure, low temperature sensitivity, inconvenience in temperature detection and the like.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the temperature sensor based on the vernier effect of the multi-wavelength fiber laser.
In order to achieve the purpose, the invention adopts the following technical scheme:
temperature sensor based on multi-wavelength fiber laser vernier effect includes: the multi-wavelength laser spectrometer comprises a pumping light source, a wavelength division multiplexer, an erbium-doped optical fiber, an optical fiber FP filter, an optical fiber Sagnac filter and a spectrometer which are sequentially arranged along the direction of a light path, wherein pumping light output by the pumping light source outputs wide-spectrum laser after passing through the wavelength division multiplexer and the erbium-doped optical fiber, the wide-spectrum laser enters multi-wavelength laser of the optical fiber FP filter, the multi-wavelength laser outputs multi-wavelength optical fiber laser signals with envelope based on vernier effect in the optical fiber Sagnac filter, and the multi-wavelength optical fiber laser signals are input into the spectrometer for measurement.
Preferably, the optical fiber Sagnac filter comprises a polarization maintaining optical fiber and an optical coupler with four ports.
Preferably, the pump light source is connected with an input port of the wavelength division multiplexer, an output port of the wavelength division multiplexer is connected with one end of the erbium-doped fiber, the other end of the erbium-doped fiber is connected with an input port of the fiber FP filter, an output port of the fiber FP filter is connected with a first port of the optical coupler, a third port of the optical coupler is connected with one end of the polarization maintaining fiber, the other end of the polarization maintaining fiber is connected with a fourth port of the optical coupler, and a second port of the optical coupler is connected with the spectrometer.
Preferably, the polarization maintaining fiber is a panda type polarization maintaining fiber, the beat length is 3.8mm, the length is 6.6m, and the working range is 1530-1580 nm.
Preferably, the working range of the optical fiber FP filter and the optical coupler is 1530-1580 nm.
Preferably, the free spectrum interval of the optical fiber FP filter at 1530nm is 0.78nm.
Preferably, the four ports of the optical coupler are all ports with a splitting ratio of 50%.
Preferably, the gain range of the erbium-doped fiber is 1530-1570 nm.
Preferably, the pump light source is a 980nm pump light source.
Preferably, the vernier effect uses the output wavelengths of the FP filter and the optical fiber sagnac filter as sliding and fixed part vernier scales respectively; the overlap between the two scales is used for measurement; the interference peaks of the two filters present peaks at wavelengths where they overlap, all peaks forming a spectral envelope, the free spectral region of the envelope satisfying:
FSR envelope ＝FSR 1 FSR 2 /|FSR 1 -FSR 2 |
wherein, FSR 1 、FSR 2 、FSR envelope Representing the free spectral ranges of the Sagnac filter, the FP filter and the envelope, respectively; when the output spectrum of the Sagnac filter has temperature drift, the temperature sensitivity is amplified by a vernier effect by M times, and the amplification factor M is as follows: m =FSR 1 /|FSR 1 -FSR 2 |。
Compared with the prior art, the invention has the beneficial effects that:
the temperature sensor based on the vernier effect of the multi-wavelength fiber laser adopts erbium-doped fibers as gain media and adopts the mixed cascade of the fiber Sagnac filter and the FP filter to control multi-wavelength output, and compared with the existing single-filter multi-wavelength fiber laser sensor, the temperature sensor has higher temperature sensitivity and can reach 10.35 nm/DEG C; the structure is simple, the cost is low, the integration of an optical fiber system is easy, the temperature sensitivity is high, and the stability of laser output is good.
Drawings
FIG. 1 is a schematic structural diagram of a temperature sensor based on vernier effect of a multi-wavelength fiber laser according to an embodiment of the present invention;
fig. 2 is a graph of the output spectra of the multi-wavelength fiber laser vernier effect based temperature sensor at 23 ℃ and 24 ℃ in the embodiment of the invention.
Detailed Description
The technical solution of the present invention is further described below by means of specific examples.
As shown in fig. 1, the temperature sensor based on the vernier effect of the multi-wavelength fiber laser according to the embodiment of the present invention includes a 980nm pump light source 1, a wavelength division multiplexer 2, an erbium-doped fiber 3, a fiber FP filter 4, an optical coupler 5 with four ports, a panda-type polarization maintaining fiber 26, and a spectrometer 7; wherein, the erbium-doped fiber 3 is used as a gain medium, and the gain range is 1530nm to 1570nm; the working ranges of the wavelength division multiplexer 2, the optical fiber FP filter 4 and the optical coupler 5 are 1530nm to 1580nm, and the free spectrum range of the optical fiber FP filter 4 at 1530nm is 0.78nm; the four ports of the optical coupler 5 are all ports with a splitting ratio of 50%, and the second port h is used as a laser output port; the panda polarization maintaining fiber 6 has a beat length of 3.8mm, a length of 6.6m and a working range of 1530nm to 1580nm.
The specific connection structure is as follows: the 980nm pump light source 1 is connected with a 980nm wavelength input port a of the wavelength division multiplexer 2, an output port b of the wavelength division multiplexer 2 is connected with one end of an erbium-doped fiber 3, the other end of the erbium-doped fiber 3 is connected with an input port of an optical fiber FP filter 4, an output port of the optical fiber FP filter 4 is connected with a first port d of an optical coupler 5, a third port e of the optical coupler 5 is connected with one end of a panda type polarization maintaining fiber 6, the other end of the panda type polarization maintaining fiber 6 is connected with a fourth port f of the optical coupler 5, a second port h of the optical coupler 5 is connected with a spectrometer 7, and the multi-wavelength temperature sensitivity of 10.35 nm/DEG C is obtained from the spectrometer 7. The embodiment of the invention adopts an optical fiber FP filter and an optical fiber Sagnac filter cascade structure consisting of a polarization maintaining optical fiber and a four-port coupler to jointly control the output waveform of the optical fiber laser, thereby obtaining a multi-wavelength optical fiber laser signal with envelope based on vernier effect; the temperature sensitivity of the individual filter output wavelengths is replaced by the temperature sensitivity of the filter cascade output envelope.
The basic principle of the temperature sensor based on the vernier effect of the multi-wavelength fiber laser is as follows: pump light output by a 980nm pump light source 1 passes through a wavelength division multiplexer 2 and then enters an erbium-doped optical fiber 3 along the wavelength division multiplexer to generate self-excitation radiation, wide-spectrum laser is output and enters an optical fiber FP filter 4 to generate multi-wavelength laser with a free spectrum interval of 0.78nm, the multi-wavelength laser enters an optical fiber Sagnac filter formed by a panda type polarization maintaining optical fiber 6 and an optical coupler 5 through a first port d of a four-port coupler 5, the free spectrum interval is 0.88nm, a multi-wavelength optical fiber laser signal enveloping the free spectrum to be 5.57nm is output based on a vernier effect, and finally the multi-wavelength optical fiber laser signal enters a spectrum analyzer (model is AQ 6370B) 7 to be observed and measured.
Vernier effect, using FP filter and fiber sagnac filter output wavelengths as sliding and fixed part vernier scales, respectively. The overlap between the two tick marks is used for the measurement. The interference peaks of the two filters will exhibit peaks at the wavelengths at which they overlap and the height of each of these peaks will be determined by the amount of overlap. The peak of the total output appears when the peaks of the two interferometers are at the same wavelength. All peaks form a spectral envelope, the Free Spectral Region (FSR) of which is given by:
FSR envelope ＝FSR 1 FSR 2 /|FSR 1 -FSR 2 |
wherein，FSR 1 、FSR 2 、FSR envelope Representing the free spectral ranges of the Sagnac filter, the FP filter and the envelope, respectively; when the output spectrum of the Sagnac filter has temperature drift, the temperature sensitivity is amplified by a vernier effect by M times, and the amplification factor M is as follows: m = FSR 1 /|FSR 1 -FSR 2 |。
The invention starts the pumping light source and adjusts the output power of the pumping light source, and controls the output power of the laser; selecting an optical fiber FP filter with proper filter characteristics, selecting an erbium-doped optical fiber and a panda type polarization maintaining optical fiber with proper lengths, generating self-excitation radiation under the action of pump light, and generating output envelope under the action of an optical fiber Sagnac filter consisting of the optical fiber FP filter, the panda polarization maintaining optical fiber and an optical coupler 5 with four ports.
The sensing process of the temperature sensor based on the vernier effect of the multi-wavelength fiber laser comprises the following steps:
1. and selecting the erbium-doped fiber in the corresponding gain range according to the output envelope range of the multi-wavelength fiber laser required to be obtained, and determining the length of the erbium-doped fiber according to the line loss.
2. And the optical circulator and the optical coupler are used for selecting an operating wavelength range to cover the output wavelength range of the multi-wavelength fiber laser to be acquired.
3. And selecting free spectrum intervals of the optical fiber FP filter according to the temperature sensitivity required to be obtained, and selecting panda polarization maintaining optical fibers with proper lengths.
4. And starting the pump light source, adjusting the output power of the pump light source, and realizing stable multi-wavelength output envelope of the multi-wavelength laser.
5. And measuring the frequency shift of the output envelope at different temperatures by a spectrum analyzer, and sensing the temperature.
Continuously tracking one trough of the output envelope of the temperature sensor with the vernier effect of the multi-wavelength fiber laser, so as to obtain the change condition of the output envelope along with the temperature, wherein as shown in fig. 2, when the temperature is changed from 23 ℃ to 24 ℃, the envelope is subjected to red shift of 10.35nm, namely, the temperature sensor with the temperature sensitivity of 10.35 nm/DEG C based on the vernier effect of the multi-wavelength fiber laser can be obtained; the temperature measurement range and the temperature sensitivity of the device are controlled by a filter device and a gain medium, and with the continuous development of various photoelectric devices, higher temperature sensitivity can be obtained, and the application of the device is wider.
While the preferred embodiments and principles of this invention have been described in detail, it will be appreciated by those skilled in the art that variations may be made in these embodiments without departing from the spirit of the invention, and these variations are to be considered within the scope of the invention.

Claims (7)

1. Temperature sensor based on multi-wavelength fiber laser vernier effect, its characterized in that includes: the device comprises a pumping light source, a wavelength division multiplexer, an erbium-doped optical fiber, an optical fiber FP filter, an optical fiber Sagnac filter and a spectrometer which are sequentially arranged along the direction of a light path, wherein pumping light output by the pumping light source outputs wide-spectrum laser after passing through the wavelength division multiplexer and the erbium-doped optical fiber, the wide-spectrum laser enters the optical fiber FP filter to form multi-wavelength laser, the multi-wavelength laser outputs multi-wavelength optical fiber laser signals with envelope based on vernier effect in the optical fiber Sagnac filter, and the multi-wavelength optical fiber laser signals are input into the spectrometer for measurement;
the optical fiber Sagnac filter comprises a polarization-maintaining optical fiber and an optical coupler with four ports;
the pump light source is connected with an input port of the wavelength division multiplexer, an output port of the wavelength division multiplexer is connected with one end of the erbium-doped fiber, the other end of the erbium-doped fiber is connected with an input port of the fiber FP filter, an output port of the fiber FP filter is connected with a first port of the optical coupler, a third port of the optical coupler is connected with one end of the polarization maintaining fiber, the other end of the polarization maintaining fiber is connected with a fourth port of the optical coupler, and a second port of the optical coupler is connected with the spectrometer;
the vernier effect respectively uses the output wavelengths of the FP filter and the optical fiber sagnac filter as sliding and fixed part vernier scales; the overlap between the two scales is used for measurement; the interference peaks of the two filters present peaks at wavelengths where they overlap, all peaks forming a spectral envelope, the free spectral region of the envelope satisfying:
FSR envelope ＝FSR 1 FSR 2 /|FSR 1 -FSR 2 |
wherein, FSR 1 、FSR 2 、FSR envelope The free spectral ranges represent the Sagnac filter, the FP filter and the envelope, respectively; when the output spectrum of the Sagnac filter has temperature drift, the temperature sensitivity is amplified by a vernier effect by M times, and the amplification factor M is as follows: m = FSR 1 /|FSR 1 -FSR 2 |。
2. The multi-wavelength fiber laser vernier effect based temperature sensor according to claim 1, wherein the polarization maintaining fiber is a panda type polarization maintaining fiber, the beat length is 3.8mm, the length is 6.6m, and the working range is 1530-1580 nm.
3. The multi-wavelength fiber laser vernier effect based temperature sensor of claim 1, wherein the working range of the fiber FP filter and the optical coupler is 1530-1580 nm.
4. The multi-wavelength fiber laser vernier effect based temperature sensor of claim 3, wherein said fiber FP filter has a free spectral spacing of 0.78nm at 1530 nm.
5. The multi-wavelength fiber laser vernier effect based temperature sensor of claim 1, wherein each of the four ports of the optical coupler is a 50% split port.
6. The multi-wavelength fiber laser vernier effect based temperature sensor as claimed in claim 1, wherein the gain range of the erbium doped fiber is 1530-1570 nm.
7. The multi-wavelength fiber laser vernier effect based temperature sensor of claim 1, wherein the pump light source is a 980nm pump light source.
CN201811609127.8A 2018-12-27 2018-12-27 Temperature sensor based on vernier effect of multi-wavelength fiber laser Active CN109556756B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811609127.8A CN109556756B (en) 2018-12-27 2018-12-27 Temperature sensor based on vernier effect of multi-wavelength fiber laser

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811609127.8A CN109556756B (en) 2018-12-27 2018-12-27 Temperature sensor based on vernier effect of multi-wavelength fiber laser

Publications (2)

Publication Number Publication Date
CN109556756A CN109556756A (en) 2019-04-02
CN109556756B true CN109556756B (en) 2023-04-14

Family

ID=65871556

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811609127.8A Active CN109556756B (en) 2018-12-27 2018-12-27 Temperature sensor based on vernier effect of multi-wavelength fiber laser

Country Status (1)

Country Link
CN (1) CN109556756B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112161723B (en) * 2020-09-04 2022-07-26 苏州易奥秘光电科技有限公司 Temperature sensor based on vernier effect of optical resonant cavity and control method thereof
CN112816096A (en) * 2021-03-08 2021-05-18 杭州电子科技大学 Cascade interferometer optical fiber temperature sensor based on vernier effect
CN113029218B (en) * 2021-03-11 2022-07-01 西北大学 Vernier effect optical fiber interference sensor demodulation device and method based on silicon-based micro-ring

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5226164B2 (en) * 2001-06-14 2013-07-03 富士通株式会社 Optical amplifier
CN102610987A (en) * 2012-02-22 2012-07-25 上海大学 Switchable multi-wavelength erbium-doped optical fiber laser based on optical fiber Mach-Zehnder interferometer
CN102751648A (en) * 2012-06-25 2012-10-24 北京航空航天大学 Anti-radiation wide-spectrum optical-fiber light source based on photo-bleaching

Also Published As

Publication number Publication date
CN109556756A (en) 2019-04-02

Similar Documents

Publication Publication Date Title
CN106248121B (en) The fiber grating sensing demodulation device and demodulation method of suppression are fluctuated under environment alternating temperature
CN109556756B (en) Temperature sensor based on vernier effect of multi-wavelength fiber laser
CN104390723B (en) Multi-wavelength Brillouin fiber laser based optical fiber temperature sensor
CN104457803A (en) Wave length demodulating system and method based on F-P etalon and reference gratings
CN103697922A (en) High-speed demodulation system of optical fiber F-P cavity sensor
Martins et al. Temperature-insensitive strain sensor based on four-wave mixing using Raman fiber Bragg grating laser sensor with cooperative Rayleigh scattering
CN203642944U (en) High-speed demodulation system of optical fiber F-P chamber sensor
RU102256U1 (en) DEVICE FOR MEASURING PHYSICAL FIELD PARAMETERS
CN103674497A (en) High accuracy measurement system of line width of narrow line width laser
CN102706451B (en) Utilize the high precision spectroanalysis instrument of excited Brillouin light loss mechanism
CN104931431A (en) FPI (Fabry-Perot interferometer) hydrogen sensor based on fiber brag grating microcavity
CN107192449A (en) Based on Fabry Perot chamber interferometry pulsed laser energy sensor and pulsed light energy measuring method
CN207557107U (en) A kind of cavity ring-down spectroscopy humidity measurement system based on intracavitary amplification
CN206862524U (en) A kind of double measurement sensors based on twin-core fiber
CN101900575B (en) Opto-sensor based on active resonant cavity and passive resonant cavity cascaded with same
CN105092085A (en) Single-mode core-dislocated fiber temperature measurement method based on dual-coupling structure having correction function
CN107063317A (en) A kind of demodulation method of multi-core optical fiber Bragg grating curvature sensor
CN107941254A (en) A kind of fiber grating sensing system and its demodulation method
CN108801500A (en) Fiber-optical grating temperature sensor based on chaos associated fiber ring attenuation and vibration technique
CN101710068B (en) Fiber gas sensor based on Fourier transform spectrometry
CN203719878U (en) A narrow linewidth laser linewidth high precision measurement system
CN103256982A (en) Method based on annular resonant cavity vernier effect for improving frequency difference measurement accuracy or wavelength difference measurement accuracy
CN111811554A (en) Optical cavity ring-down-based large-range high-precision fiber grating sensing method and device
CN204807443U (en) FPI hydrogen sensor based on fiber grating microcavity
CN205449324U (en) Device based on dislocation optic fibre temperature measurement is realized to laser beat frequency

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