Laser relative intensity noise suppression of micro-grating accelerometer based on reference differential detection method

A reference differential detection method (RDDM) for micrograting accelerometers is described to suppress laser relative intensity noise (RIN). A three orders-differential scheme and reference detection method are combined to complement the output and to reduce the background light interference. A theoretical model of RDDM to suppress RIN is established and analyzed based on the scalar diffraction theory. Then the reference differential detection circuit (RDDC) parameters are designed to achieve the optimal sensitivity for the accelerometer based on the model. Experimental results indicate the sensitivity of the micrograting accelerometer is 2.22 VMg. The overall signal-to-noise ratio of this method is improved by 7.3 dB at 100 Hz and the noise level is obviously reduced compared with that of the device without RDDM.