Low-Frequency Effectiveness of Differential Detection for Electro-optic Sensor System

This paper describes the effectiveness of differential detection for reducing laser noise in the low-frequency region in an electro-optic (EO) sensor system. Improvement in the signal-to-noise ratio (SNR) is necessary for expanding the applications of EO sensor systems. In a previous work, an alternating current coupling was used at an optical receiver to eliminate a direct current (DC) signal. As a result, the low-frequency effectiveness of the differential detection could not be estimated. Therefore, in this study, we modified a photodiode bias circuit for DC coupling measurement.