Optimization Design And Realization Of Temperature And Vibration Performance Of Flat Er-Doped Fiber Source

Interferometric fiber optic gyroscope(IFOG)has been wide used as the core angular rate sensor of inertial navigation system(INS).The flat erbium-doped superfluorescent fiber source(ED-SFS)as the key component of IFOG has the advantages of high output power,excellent stability and wide spectrum,and its performance affects the output characteristics of the gyro directly.Aiming at the problem that the performance of ED-SFS deteriorates under temperature and vibration conditions,which affects the performance of IFOG.This paper carried out the optimization design and realization method of the temperature and vibration performance of ED-SFS.First,the hardware module of the ED-SFS is designed,meanwhile,the optimized incremental differential ahead PID(IDA-PID)feedback control algorithm is applied to the optical power control system of ED-SFS,which improves the power stability of the light source.Secondly,in response to the requirements of wavelength thermal stability of ED-SFS,scale factor thermal stability of FOG and wavelength vibration stability of ED-SFS in the actural special application environment,three improved methods are proposed and performance experimental verification is completed.The main research work is as follows:1.Aiming at the problem of the optical power of ED-SFS changing with temperature,the IDA-PID feedback control algorithm is applied to the light source optical power control system.Part of signal light output by the ED-SFS is input to the photoelectric monitoring diode for photoelectric conversion,and then the converted voltage digital quantity is compared with the set value.After that,the error value is processed and the IDA-PID control algorithm is written into the light source circuit controller.Experiments show that,compared with traditional positional-PID and incremental-PID control algorithm,the IDA-PID control algorithm can improve the power stability within the full temperature range(-40? to+60?)by 0.5%.2.Aiming at the problem that the mean wavelength of the ED-SFS changes with temperature,a highly stable ED-SFS based on the Fresnel reflection effect is proposed and designed.The relationship between reflectivity and cutting angle is analyzed first,and then the EDF pigtail is processed by 90° vertical cutting to obtain a half-doule-pass configuration with simplified optical path,lower cost and excellent mean wavelength thermal stability.Experiments show that,compared with the traditional welding method of Faraday rotating mirror(FRM)and fiber mirror(FM),the proposed method improves the mean wavelength stability of EF-SFS within the full temperature(-40? to+60?)by more than 100ppm.3.Aiming at the problem that the scale factor of the IFOG changes with temperature,a method is proposed to compensate the temperature stability of scale factor by using the temperature characteristics of the positive temperature-dependent ED-SFS(PT-EDSFS).The chirped grating filter flatten is selected as the the flattening filter to obtain the ED-SFS whose mean wavelength changes in a positive correlation with temperature which compensates the scale factor linearity error caused by temperature changes of fiber sensitive coil effectively.Experiments show that,the use of PT-EDSFS can reduce the full-temperature(-40? to+60 ?)scale factor error of IFOG by more than 500ppm(before temperature compensation).4.Aiming at the problem that the mean wavelength of ED-SFS changes with vibration,a vibration-resistant ED-SFS is proposed and designed.Combined with the actual vibration environment of IFOG,the introduction of the 45° FRM into one-stage configuration of ED-SFS eliminates the optical path noise caused by the fluctuation of polarization state during the vibration process,especially during the high-frequency vibration process.Experiments show that the proposed scheme can improve the mean wavelength stability under vibration conditions,especially the mean wavelength stability under high-frequency vibration conditions(1000Hz-2000Hz)by 6.8ppm.The research in this paper has certain theoretical and engineering significance for further improving the performance of the ED-SFS and FOG under special application environments such as high-low temperature and vibration condition.