Beam-splitting ratio impact on the SNR for the balanced heterodyne

Considered the beam-splitting ratio, the mathematical model of balanced heterodyne receiver is established, and the mathematical expression of the relationship between the signal-to-noise ratio and the beam-splitting ratio is obtained. Based on the experiment, we got the best range of beam-splitting ratio which is 0.159-0.5. The experiment results show that, in the framework of the best beam-splitting ratio, the balanced heterodyne receiver has better signal-to-noise ratio than the common heterodyne receiver.