Chirped pulse heterodyne for optimal beat note detection between a frequency comb and a continuous wave laser.

Chirped pulse heterodyne is proposed to maximize the signal-to-noise ratio (SNR) when measuring the beat note between an optical frequency comb and a continuous wave (CW) laser. The noise model reveals that all the comb power within the largest possible detection bandwidth can be used to increase the SNR. The chirped comb/CW interference experiment is shown to be equivalent to CW/CW interference, using the comb's spectrally available power. The approach can also greatly alleviate dynamic range issues when detected pulsed heterodyne signals. A beat note SNR of 68.3 dB in a 100 kHz bandwidth is achieved.