Research On High Precision Spectral Measurement Technology Based On Brillouin Effect

Optical fiber communication technology has been bringing about significant changes in the field of technology and society.As an important application of laser technology,laser information technology,mainly represented by optical communication technology,has built the framework of modern communication network and become the main component of information transmission.Optical fiber communication technology as the backbone part of the communication network,bearing huge upgrading pressure,high speed,large capacity optical fiber communication system and network is the mainstream development direction of optical communication technology.With the increasing speed of optical fiber communication system,spectrum analyzer becomes more and more important measuring instrument.Spectrometers play an indispensable role in testing various components of optical fiber communication system.With the increasing demand for spectral fine structure observation,the research of high precision spectral measurement technology has become a key issue.In this thesis,the Brillouin Optical Spectrum Analyzer(BOSA)technology based on stimulated Brillouin scattering effect in optical fibers was studied,and the BOSA spectral measurement scheme was designed and verified by simulation.To solve the problem of environmental disturbance,a high-precision measurement scheme(Heterodyne MixingBrillouin Optical Spectrum Analyzer)based on heterodyne mixing was proposed.Aiming at the problems of high hardware cost and high computational complexity in BOSA spectral measurement system,a spectral measurement scheme based on piecewise cubic Hermite interpolation algorithm and a spectral measurement scheme based on piecewise cubic spline interpolation algorithm are proposed.The main research work of this paper is as follows:(1)Studied and designed the scheme of BOS A spectral measurement system,built the simulation platform of BOSA spectral measurement system in Optisystem simulation software,and simulated and verified the key performance indicators of spectral measurement,proving that the built spectral measurement system can meet the performance requirements of BOSA spectral measurement system.The wavelength resolution of 0.25pm is realized in the simulation.(2)In order to solve the problem that the excited Brillouin effect in optical fiber is easily disturbed by environmental factors,a Brillouin spectrum measurement scheme based on heterodyne mixing is proposed,and the HM-BOSA spectrum measurement system is built in Optisystem simulation software,and the environmental disturbance problem is simulated and verified.The results show that,under the same disturbance of environmental factors,the wavelength inaccuracy of BOSA spectral measurement system is greatly affected,reaching 2.72pm.The wavelength inaccuracy of HM-BOSA spectral measurement system is 1.8pm.When disturbed by environmental factors,HM-BOSA can significantly improve the wavelength accuracy.(3)In order to solve the problems of BOSA Brillouin spectral measurement system,such as high hardware requirements and high operational complexity,the piecewise cubic Hermite interpolation algorithm and piecewise cubic spline interpolation algorithm are proposed respectively.By introducing interpolation algorithm into the data processing module,the accuracy requirements of related hardware in the spectrum measurement system are reduced,and the measurement requirements of BOSA spectrum measurement system can be met,thus reducing the overall cost and complexity of the spectrum measurement system.The simulation results show that the spectral center frequency measured by the spectral measurement system based on piecework cubic Hermite interpolation algorithm is offset by 100MHz compared with the real center frequency of the signal to be measured,and the corresponding wavelength inaccuracy is 0.8pm.The spectral center frequency measured by the spectral measurement system based on piecewise cubic spline interpolation algorithm is offset by 93 MHz compared with the real frequency of the signal to be measured,and the corresponding wavelength inaccuracy is 0.744pm.