CN105758626A - Testing system for measuring ultra-narrow line width of 852 nm semiconductor laser unit based on delayed self-heterodyne method - Google Patents
Testing system for measuring ultra-narrow line width of 852 nm semiconductor laser unit based on delayed self-heterodyne method Download PDFInfo
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Abstract
The invention discloses a testing system for measuring the ultra-narrow line width of an 852 nm semiconductor laser unit based on a delayed self-heterodyne method, and belongs to the field of the semiconductor optoelectronic technology.The testing system comprises the semiconductor laser unit, a first 3dB coupler, a time delay multimode fiber, an acousto-optic frequency shifter, a second 3dB coupler, a photoelectric detector and a frequency spectrograph.An output port of the semiconductor laser unit is an FC/PC fiber interface, and the semiconductor laser unit is connected with an input port of the first 3dB coupler through a flange plate.Output of the first 3dB coupler includes two paths, one path is connected with the time delay multimode fiber through a flange plate, and the other path is connected with the acousto-optic frequency shifter through a flange plate.Output of the time delay multimode fiber and output of the acousto-optic frequency shifter are combined into one through the second 3dB coupler.The output end of the second 3dB coupler is connected with the photoelectric detector, and the output end of the photoelectric detector is connected with the frequency spectrograph through a BNC radio frequency cable.The line width of the 852 nm semiconductor laser unit can be measured, and the precision of the testing system can be guaranteed.
Description
Technical field
The present invention relates to the test system of narrow linewidth semiconductor laser live width, belong to field of semiconductor photoelectron technique, be specifically related to the live width test system of a kind of 852nm narrow linewidth semiconductor laser.
Background technology
Narrow linewidth semiconductor laser, because of its line width, the performance such as noise is low, electromagnetism interference is strong, is widely used in Fibre Optical Sensor, oil exploration, pipe monitoring, laser radar and submarine communication and other high accuracy spectral measurement fields.Wherein 852nm narrow linewidth semiconductor laser is mainly used in the fields such as Cs atom frequency spectrum, junction service, and the linewidth requirements of laser instrument is more and more higher.Bandwidth is measuring of light-source monochromaticity, and monochromaticity is more good, and coherence time is more long.Therefore, the live width accurately measuring these laser instrument is necessary for the performance evaluating single-frequency laser.
The measuring method of spectral line width substantially has three kinds: spectrometer measurement method, F-P interferometric method, beat frequency method spectrogrph certainty of measurement be about 100GHz, F-P interferometric method certainty of measurement and be about 100MHz, beat frequency method precision then can reach below 100kHz.Heterodyne method is to measure the comparatively ideal method of very narrow linewidth, it is possible to obtain satisfied resolution.
Laser linewidth field tests generally concentrates on 1310nm and 1550nm semiconductor laser, owing to being subject to wavelength restriction, relatively fewer for the semiconductor laser super-narrow line width test that wave band is 852nm, conventional narrow live width test system is no longer tested suitable in the laser linewidth of special wave band.But, the laser instrument demand of 852nm also increases day by day, so the super-narrow line width test system for special wave band has quite wide application prospect.
Summary of the invention
It is an object of the invention to provide the live width of a kind of 852nm narrow linewidth laser test system.Core texture is tradition Mach-Zehnder interferometer system, and the light sent from laser instrument is through three-dB coupler so that a road incident illumination is divided into two-way, will a wherein road light fiber delay time, and another light path carries out shift frequency by frequency shifter.The light path of time delay and shift frequency makes two-way light clap mutually then through a three-dB coupler, through opto-electronic conversion, obtains the photoelectric current spectral line after clapping mutually, determine laser linewidth from time delay photoelectric current spectral line on spectrum analyzer.The Line-width precision of the test system and test of the present invention can reach below 100kHz.
Being different from other laser linewidth test system, the present invention is applicable to the operation wavelength measurement at the laser linewidth of 852nm, the domestic laser linewidth rarely having laboratory to remove to build co-wavelength test system.Additionally, Transmission Fibers used in the present invention is multimode fibre, it was demonstrated that multimode fibre can also be used for fiber delay time self-heterodyne test system.Additionally, due to the optical fiber multimode fibre price of transmission 852nm laser is high, through the derivation of equation, time delay optical fiber is more long, and detectable Line-width precision is more high.But, more long time delay optical fiber, caused loss also will increase.We have weighed the stake of precision, loss and cost, and finally we are used for time delay with relatively short multimode fibre, and meet test request.
A kind of 852nm narrow linewidth semiconductor laser live width test system, specifically includes that
Semiconductor laser (1), the first three-dB coupler (2), time delay multimode fibre (3), acousto-optic frequency shifters (4), the second three-dB coupler (5), photodetector (6) and audiofrequency spectrometer (7) composition；
Semiconductor laser output port is the optical fiber interface of FC/PC, is connected by the input port of semiconductor laser and the first three-dB coupler by ring flange；First three-dB coupler is output as two-way, and ring flange of leading up to connects time delay multimode fibre, and ring flange of separately leading up to connects acousto-optic frequency shifters；Second three-dB coupler is combined into a road the output of time delay multimode fibre and the output of acousto-optic frequency shifters；The outfan of the second three-dB coupler connects photodetector, and the outfan of photodetector uses BNC radio frequency line to be connected with audiofrequency spectrometer.
Described semiconductor laser is 852nm narrow linewidth semiconductor laser, and excitation wavelength is 852nm, and exiting surface is coated with the reflectance antireflective film less than 0.01%, and another side is coated with the reflectance high-reflecting film more than 90%；
The first described three-dB coupler and the second three-dB coupler, splitting ratio is all 50/50, and fiber type is multimode fibre, and fibre-optical splice is FC/PC；
Described multimode time delay optical fiber, operation wavelength is at 850-852nm, and time delay optical fiber loss is 3.5dB/km, and core diameter is 50 μm, and the refractive index of fibre core is 1.5, and fibre-optical splice is FC/PC；
Described acousto-optic frequency shifters is the frequency shifter for 850nm design, and working media is TeO2, operating central wavelength is 850-852nm, and shift frequency value is 100MHz, and maximum insertion is 2dB；
Described photodetector detection is fixed gain silicon detector, and detection material is Si, and operating wavelength range is from 200nm to 1100nm, responsiveness at 850-852nm place is 0.35A/W, bandwidth is 150MHz, has fixing gain module, and amplification reaches 5000 times；
Described spectrum analyzer is for the frequency-domain analysis of radiofrequency signal, based on fast Fourier transform, by Fourier's computing, measured signal being resolved into acquisition frequency spectrum profile after discrete frequency component processes, bandwidth is 100kHz-3.6GHz, and resolution has reached 100Hz.
The first described three-dB coupler is that the output light of laser instrument is divided into two-way；Described multimode fibre is used for time delay；Described acousto-optic frequency shifters is used for shift frequency；The second described three-dB coupler is that the light path of shift frequency Yu time delay is carried out beat frequency；Described photodetector converts optical signal into the signal of telecommunication, and is amplified by the signal of telecommunication；Described audiofrequency spectrometer will obtain photoelectric current spectral line, and be determined the live width of laser instrument by photoelectric current spectral line.This test system accuracy can reach 100kHz, and beat frequency is positioned near the intermediate frequency of non-zero-frequency, it is to avoid the low-frequency disturbance that system is brought by surrounding enviroment, thus reducing systematic error, improving certainty of measurement.
What the present invention brought has the beneficial effect that:
The live width of 852nm semiconductor laser can be measured, and when reducing time delay optical fiber length as far as possible, it is ensured that the degree of accuracy of test system, the minimum feature can surveyed in theory is about 100kHz, provides cost savings simultaneously.
Accompanying drawing explanation
Fig. 1 is the test system schematic of 852nm narrow linewidth semiconductor laser live width；
In Fig. 1: 1, semiconductor laser, the 2, first three-dB coupler, 3, multimode time delay optical fiber, 4, acousto-optic frequency shifters, the 5, second three-dB coupler, 6, photodetector, 7, audiofrequency spectrometer.
Fig. 2 is 852nm narrow linewidth semiconductor laser live width test spectrogram, and laser linewidth is 100kHz, the spectrogram of test when centre wavelength is 852nm.
Detailed description of the invention
As it is shown in figure 1, the test system of a kind of 852nm narrow linewidth semiconductor laser live width, mainly include 852nm semiconductor laser, the first three-dB coupler, multimode time delay optical fiber, acousto-optic frequency shifters, the second three-dB coupler, photodetector, spectrum analyzer；
The method realizing the test system of 852nm narrow linewidth semiconductor laser live width below in conjunction with Fig. 1 introduction；
Step 1,852nm narrow linewidth semiconductor laser output port are the optical fiber interface of FC/PC, are connected by the input port of laser instrument and the first three-dB coupler by ring flange；
Step 2, the first three-dB coupler are output as two-way, and ring flange of leading up to connects multimode time delay optical fiber, and ring flange of separately leading up to connects acousto-optic frequency shifters.Additionally, acousto-optic frequency shifters needs the working power of additional 24V to be its power supply；
Step 3, with the second three-dB coupler, the output of multimode time delay optical fiber Yu acousto-optic frequency shifters is combined into a road；
Step 4, the second three-dB coupler outfan connect photodetector, photodetector need 12V D.C. regulated power supply for its power；
Step 5, photodetector outfan use BNC radio frequency line be connected with spectrum analyzer；
Step 6, opening audiofrequency spectrometer, mid frequency is arranged on 100MHz, adjusts waveform on the display screen of audiofrequency spectrometer, and at central peak decline 3dB place, reading breadth of spectrum line herein, this width is the twice of the live width of semiconductor laser.Therefore have only to measure the breadth of spectrum line of photoelectric current, it is possible to accurately obtain the live width of measured laser device.
Claims (7)
1. a 852nm narrow linewidth semiconductor laser live width test system, it is characterised in that specifically include that
Semiconductor laser (1), the first three-dB coupler (2), multimode time delay optical fiber (3), acousto-optic frequency shifters (4), the second three-dB coupler (5), photodetector (6) and audiofrequency spectrometer (7) composition；
Semiconductor laser output port is the optical fiber interface of FC/PC, is connected by the input port of semiconductor laser and the first three-dB coupler by ring flange；First three-dB coupler is output as two-way, and ring flange of leading up to connects time delay multimode fibre, and ring flange of separately leading up to connects acousto-optic frequency shifters；Second three-dB coupler is combined into a road the output of multimode time delay optical fiber and the output of acousto-optic frequency shifters；The outfan of the second three-dB coupler connects photodetector, and the outfan of photodetector uses BNC radio frequency line to be connected with audiofrequency spectrometer.
2. a kind of 852nm narrow linewidth semiconductor laser live width test system described in claim 1, it is characterized in that, described semiconductor laser is 852nm narrow linewidth semiconductor laser, excitation wavelength is 852nm, exiting surface is coated with the reflectance antireflective film less than 0.01%, and another side is coated with the reflectance high-reflecting film more than 90%.
3. a kind of 852nm narrow linewidth semiconductor laser live width test system described in claim 1, it is characterised in that the first described three-dB coupler and the second three-dB coupler, splitting ratio is all 50/50, and fiber type is multimode fibre, and fibre-optical splice is FC/PC.
4. a kind of 852nm narrow linewidth semiconductor laser live width test system described in claim 1, it is characterised in that multimode time delay optical fiber, operation wavelength is at 850-852nm, and time delay optical fiber loss is 3.5dB/km, and core diameter is 50 μm, the refractive index of fibre core is 1.5, and fibre-optical splice is FC/PC.
5. a kind of 852nm narrow linewidth semiconductor laser live width test system described in claim 1, it is characterised in that described acousto-optic frequency shifters is the frequency shifter for 850nm design, and working media is TeO2, operating central wavelength is 850-852nm, and shift frequency value is 100MHz, and maximum insertion is 2dB.
6. a kind of 852nm narrow linewidth semiconductor laser live width test system described in claim 1, it is characterized in that, photodetector detection is fixed gain silicon detector, detection material is Si, operating wavelength range is from 200nm to 1100nm, and the responsiveness at 850-852nm place is 0.35A/W, and bandwidth is 150MHz, having fixing gain module, amplification reaches 5000 times.
7. a kind of 852nm narrow linewidth semiconductor laser live width test system described in claim 1, it is characterized in that, described audiofrequency spectrometer is for the frequency-domain analysis of radiofrequency signal, based on Fourier transformation, frequency spectrum profile is obtained after discrete frequency component process being resolved in measured signal by Fourier's computing, bandwidth is 100kHz-3.6GHz, and resolution reaches 100Hz.
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| CN108020824A (en) * | 2017-11-28 | 2018-05-11 | 中国科学院电子学研究所 | The method that SAL signal coherencies based on local oscillator digital delay are kept |
| CN108155540A (en) * | 2017-12-28 | 2018-06-12 | 浙江嘉莱光子技术有限公司 | A kind of detecting system of single-frequency laser mode hopping |
| CN108519163A (en) * | 2018-04-16 | 2018-09-11 | 浙江大学 | The direct modulation light of simulation based on chirp measurement feedback control carries radio frequency link device |
| CN109238658A (en) * | 2018-09-12 | 2019-01-18 | 电子科技大学 | The measurement method and device of the delay parameter of light delay device |
| CN109613408A (en) * | 2019-02-01 | 2019-04-12 | 深圳供电局有限公司 | Discharge detector |
| CN110118643A (en) * | 2019-04-17 | 2019-08-13 | 华中科技大学 | A kind of the laser linewidth measurement method and device of the extraction of power spectrum bicharacteristic parameter |
| CN111189619A (en) * | 2020-01-10 | 2020-05-22 | 全球能源互联网研究院有限公司 | Device and method for measuring laser tuning precision |
| CN111351569A (en) * | 2020-02-22 | 2020-06-30 | 山西大学 | Device and method for measuring line width of continuous laser |
| CN112129491A (en) * | 2020-10-23 | 2020-12-25 | 南京航空航天大学 | Optical fiber time delay measuring method and device based on single-optical-frequency comb interference |
| CN112432767A (en) * | 2020-10-26 | 2021-03-02 | 中国电子科技集团公司第二十九研究所 | Method and device for measuring wavelength drift range of laser based on optical delay self-heterodyne |
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| CN108020824A (en) * | 2017-11-28 | 2018-05-11 | 中国科学院电子学研究所 | The method that SAL signal coherencies based on local oscillator digital delay are kept |
| CN108020824B (en) * | 2017-11-28 | 2021-08-13 | 中国科学院电子学研究所 | SAL signal coherence maintaining method based on local oscillator digital delay |
| CN108155540A (en) * | 2017-12-28 | 2018-06-12 | 浙江嘉莱光子技术有限公司 | A kind of detecting system of single-frequency laser mode hopping |
| CN108519163A (en) * | 2018-04-16 | 2018-09-11 | 浙江大学 | The direct modulation light of simulation based on chirp measurement feedback control carries radio frequency link device |
| CN109238658A (en) * | 2018-09-12 | 2019-01-18 | 电子科技大学 | The measurement method and device of the delay parameter of light delay device |
| CN109613408A (en) * | 2019-02-01 | 2019-04-12 | 深圳供电局有限公司 | Discharge detector |
| CN110118643B (en) * | 2019-04-17 | 2020-10-16 | 华中科技大学 | Laser line width measuring method and device for power spectrum double-characteristic parameter extraction |
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| CN111189619B (en) * | 2020-01-10 | 2022-06-03 | 全球能源互联网研究院有限公司 | Device and method for measuring laser tuning precision |
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| CN111351569A (en) * | 2020-02-22 | 2020-06-30 | 山西大学 | Device and method for measuring line width of continuous laser |
| WO2021227992A1 (en) * | 2020-05-09 | 2021-11-18 | 中国科学院国家授时中心 | Apparatus and method for measuring laser linewidth based on cyclic self-heterodyne method |
| CN112129491A (en) * | 2020-10-23 | 2020-12-25 | 南京航空航天大学 | Optical fiber time delay measuring method and device based on single-optical-frequency comb interference |
| CN112432767A (en) * | 2020-10-26 | 2021-03-02 | 中国电子科技集团公司第二十九研究所 | Method and device for measuring wavelength drift range of laser based on optical delay self-heterodyne |
| CN112432767B (en) * | 2020-10-26 | 2022-11-29 | 中国电子科技集团公司第二十九研究所 | Method and device for measuring wavelength drift range of laser based on optical delay self-heterodyne |
| CN113091901A (en) * | 2021-04-08 | 2021-07-09 | 雄安创新研究院 | Wavelength coding laser spectrum line width testing device and testing method thereof |
| CN114427956A (en) * | 2022-01-26 | 2022-05-03 | 重庆大学 | Frequency sweep laser intrinsic line width measuring system and method based on fractional Fourier transform |
| CN114427956B (en) * | 2022-01-26 | 2022-11-18 | 重庆大学 | Frequency sweep laser intrinsic line width measuring system and method based on fractional Fourier transform |
| CN117073990A (en) * | 2023-10-16 | 2023-11-17 | 常州灵动芯光科技有限公司 | Linewidth testing system and method for narrow linewidth laser |
| CN117073990B (en) * | 2023-10-16 | 2024-01-26 | 常州灵动芯光科技有限公司 | Linewidth testing system and method for narrow linewidth laser |
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Application publication date: 20160713 |