Laser frequency noise induced error in resonant fiber optic gyro due to an intermodulation effect

Abstract

For the first time, a significant noise source in the resonant fiber optic gyroscope (RFOG) called intermodulation induced error is proposed and deeply analyzed in this paper. The intermodulation error is produced by the laser frequency noise at even multiples of the modulation frequency due to an intermodulation effect, which will seriously limit the random noise performance of the RFOG. Experiments are designed and conducted to verify and measure the intermodulation induced error in the RFOG. The experimental results confirm the existence of intermodulation error, and fit well with the theory. As for the design of the RFOG, light sources with a narrow intrinsic linewidth and a high modulation frequency are preferable to achieve a high rotation-rate sensitivity.

Resonant fiber optic gyroscope based on sideband locking of dual-light sources

“…Backscattering noise, polarization noise, and optical Kerr noise are considered to be the three most influential optical noise sources 7 – 9 Backscattering noise, in particular, is regarded as the most critical factor limiting gyroscope performance 10 , 11 . Backscattering noise in RFOGs manifests in two forms: noise caused by interference between backscattered light and signal light and noise arising from backscattered light itself, leading to output offsets.…”

Suppression Method of Optical Noises in Resonator-Integrated Optic Gyroscopes

“…The shot-noise of the photodetector determines the ultimate sensitivity of the RIOG. However, many characteristics, including backscattering [10][11][12][13][14][15][16][17][18][19][20][21][22], back-reflection [23][24][25][26][27][28], nonlinear Kerr effect [29][30][31][32][33][34][35][36][37], polarization fluctuation [38][39][40][41][42][43][44][45][46][47][48][49][50], and laser frequency noise [51][52][53], have negative impacts. These negative impacts degrade the performance of RIOGs and make it worse than the shot-noise limited theoretical sensitivity.…”