Relative intensity noise reduction with fiber ring resonator

A method of reducing the relative intensity noise (RIN) using a fiber ring resonator to improve the angular random walk (ARW) of a fiber optic gyroscope (FOG) is demonstrated. The RIN at the proper frequency fp degrades the ARW of the FOG when the detected power reaches tens of microwatts. Adding a fiber ring resonator between the source and the interferometer periodically modulates the optical spectrum and consequently reduces the RIN at fp. The reduction in the RIN is analyzed theoretically and experimentally. An experiment demonstrated a 5.2-dB decrease in the RIN at fp, which reduces the standard deviation by 2.6-dB. The ARW was reduced from 870 to 580 μdeg/h1∕2, which amounts to a 1.8-dB reduction.