Research On Enhancement Signal-to-noise Ratio Of Resonant Optical Gyroscope

The optical resonator has the characteristics of high quality factor and very small volume of the model,so it has been widely concerned and developed in the field of ultra-high sensitivity sensing application.As the core unit of resonant optical gyroscope and the good carrier of high sensitivity,this paper studies the key technical indexes of resonant optical gyroscope system.Based on the Sagnac effect,this paper analyzes the principle of resonant cavity transmission and the working principle of resonant optical gyroscope.It is pointed out that improving the signal-to-noise ratio of gyroscope is the key to obtain high-precision gyroscope.However,due to the sensitive mechanism and detection principle of the gyro system,the application of resonant optical gyroscope is also facing many challenges,including: the frequency difference between the two optical signals is very weak(usually in the n V order),signal detection strongly dependent on the system The reciprocity and so on.These challenges are focused on how to improve the effective signal in the gyro system(ie,to obtain a larger scale factor)and how to suppress the main noise that affects the gyro output,ie,intensity noise,back noise,and polarization noise.In this paper,we focus on the application of high-Q optical resonator gyroscope system to carry out the key technology of improving signal to noise ratio.Related research content can be summarized as the following aspects:1.the analysis and suppression of the gyro system optoelectronic devices introduced two kinds of intensity noise.Aiming at the strength noise of the semiconductor laser,the second harmonic solution is proposed.The response time of the scheme is less than 0.1ms,and the intensity modulation range is up to 6m W,which can meet the practical application of the gyro system.Aiming at the residual intensity modulation of the phase modulator,the solution of the single phase modulator is proposed for the first time and the test system is built.The noise of the system introduced by the residual intensity modulation is reduced to below the limit sensitivity.2.Theoretical and experimental analysis The dual-Faraday rotation system is used to suppress the non-reciprocal noise in the gyro system,and the symmetry of the resonant spectrum is greatly improved.Aiming at the nonreciprocal noise in the optical path of the resonant optical gyroscope system,the suppression scheme of the double-Faraday rotation system is proposed for the first time.The back-to-noise and polarization fluctuation noise suppression performance of the scheme is tested.The test results show that:1)The double Faraday rotation system has good compatibility with the resonant optical gyro system.The double Faraday rotary system has a low insertion loss(0.51 d B),and the optical path structure has a strict reciprocity to meet the work requirements of the gyro system.2)The double Faraday rotation system can suppress nonreciprocal noise in resonant optical gyro systems.A kind of backscattering noise in the gyroscope system is analyzed,and the echo suppression method is proposed to suppress the two kinds of backscattering noise at the same time,and the high echo suppression ratio of 112 d B is realized.The noise is suppressed to below the limit sensitivity,and the conventional method of suppressing the backscattering noise by the carrier suppression method is broken.Using the Jones matrix,the polarization mathematical model of the double Faraday rotation system is established,the polarization fluctuation noise in the gyro system is analyzed,and the polarization angle of the polarization system is 89.757 ° and the polarization extinction ratio is 25.35 d B,and the polarization fluctuation Noise suppression below limit sensitivity.The active resonant cavity system based on erbium-doped fiber as the gain medium is proposed,and the active resonator gyroscope system is built and tested accordingly.The active gain mechanism of the eruption doped with erbium ions at the physical level is analyzed.Combined with the gyro system,the transmission loss is compensated by the active resonator pump gain compensation,and the active resonant cavity with transmission resonant characteristics is proposed Has a larger scale factor,and through the experimental test to compare the active resonant cavity than the passive resonator scale factor increased 2.7 times to achieve the signal to noise ratio increase.