Application of the Wiener filter for intensity noise reduction in fiber optic gyroscopes.

An essential issue for the low-noise system application of the fiber optic gyroscope (FOG) is to reduce its noise level. The relative intensity noise (RIN) of the light source is the dominant noise of the FOG when the light power on the detector reaches a certain level. The noise subtraction method is effective for RIN reduction and easy to implement in a FOG. This paper theoretically analyzes the factors that influence the result of the method and deduces the function to calculate the noise suppression ratio that can be achieved. A method that uses an optimum filter design based on the Wiener filter in the reference detector signal is proposed to improve the subtraction result. A FOG system is set up to test the feasibility of the method. The experiment results meet with the theoretical analysis, and by using the Wiener filter, the achieved noise subtraction factor reaches the limitation that restrains the optical system and detection circuit.