Modeling and Optimization of the OFC Spectral Filtering for High SNR Interference with CW Lasers

To reference continues wave (CW) lasers to optical frequency combs (OFCs) in precision measurements, the SNR of their beat signal is usually required to be over 30 dB. It can be achieved by the OFC spectral filtering method. However, this method has not been thoroughly modeled and the system cannot be optimized. In this paper, the beat signal SNR is modeled by analyzing the interference spectrum and photodiode shot-noise. With this model, the system parameters are optimized to achieve the ideal SNR of 46.5 dB and practical SNR of 43 dB (Resolution Bandwidth=2.2 MHz). We believe the presented scheme can promote a wider application of the OFC referenced CW lasers by ensuring the high SNR interference.