The Research On Erbium Doped Fiber Source With High Power And Gaussian Spectrum For Ultrahigh-Precision Fiber Optic Gyroscope

With the development of optical fiber communication components and digital signal processing,not only does the life expectancy of the interferometric FOGs improve,but alsoits accuracy is breaking through the performance limitations of traditional mechanical gyros and laser gyros.Ultra-high precision has become an important advantage of interferometric FOGs.Its application directions include space orientation,strategic missile guidance,and inertial navigation of submarines.Foreign-subsidiary inertial navigation systems for submarines based on FOGs at 1nmile/month have been reported and researched continuously.The zero-bias stability has achieved 0.0001°/ h.High-power Gaussian broadband erbium-doped fiber source is a key component of ultra-high-precision fiber optic gyro.It has the advantages of high power,good wavelength stability and so on.It is of great significance to achieve zero-bias stability of ultra-high-precision fiber optic gyroscopes and stability of scale factors better than 1ppm.In this paper,theoretical and experimental studies on high-power Gaussian-doped erbium-doped fiber light sources have been carried out based on the research needs of ultra-high-precision fiber optic gyros.On the base of the research of relevant domestic and foreign data,the design scheme of dual-pass backward and Gaussian filtering high-power broadband erbium-doped fiber source was determined;the establishment of a fiber-optic gyro random walk coefficient model,light source coherence analysis,and scale factor error were studied.Etc.;the design goal of an ultra-high-precision fiber-optic ytterbium-doped erbium-doped fiber light source was established;for the performance requirements of the light source,optical components such as pump lasers and wavelength division multiplexers that make up the light source were selected and tests;Through a large number of temperature-related orthogonal experiments,the design parameters of the pump power and erbium fiber length of the erbium-doped fiber light source were optimized.On this basis,a high-power light source driver circuit is designed and constructed to create an experimental prototype of a high-power Gaussian spectrum Erbium-doped fiber source.The general technical specifications of the Erbium-doped fiber source,as well as the full-temperature power stability and full-temperature wavelength stability were measured.Finally,the erbium-doped fiber source prototype was assembled on a fiber optic gyro,and the preliminary gyro bias stability and random walk coefficient test results were given.Thetest results of high-power Gaussian spectrum Erbium-doped fiber light source experimental prototype are as follows: output power 34mW(300mA drive current),full temperature(-40 °C ~ 60 °C)power stability 0.8%;spectral width of 10.8nm,and output spectrum is near Gaussian spectrum;spectral modulation degree less than 0.1dB,asymmetry-21dB;average wavelength stability at room temperature(25°C)is less than 5ppm,average wavelength stability at full temperature(-40°C to 60°C)is less than 20 ppm.The test results of the experimental prototype meet the preliminary design goals.The experimental prototype test results meet the preliminary design goals.Gyro-level preliminary debugging shows that the high-power Gaussian spectrum light source experimental prototype(30mW/10nm)is reduced by about a quarter compared to the low-power light source(10mW/8nm).