Laser Excess Noise Reduction in Optical Phase Shift Measurements

We describe and demonstrate an optical detection scheme for small electro-optic phase shift measurements. The scheme increases the modulation depth due to the electro-optic effect and allows broadband reduction of laser excess noise in balanced dual-differential detection ssystems. The scheme is applied in electro-optic phase shift measurement setup for integrated circuit testing, where the excess laser noise is reduced by ~20 dB.