Time-multiplexed electro-optic modulation for enhanced signal to noise ratio and recording speed in dual frequency comb spectroscopy

We demonstrate a novel technique to improve the signal-to-noise ratio (SNR) and/or alternatively the recording speed of dual comb spectroscopy (DCS) through time multiplexing of the interferograms. The all-fiber architecture utilizes electro-optic modulators (EOM) to generate two optical frequency combs. By engineering the pulse trains, the interferogram is time-multiplexed, or, in other words, includes a larger number of bursts within a given time frame compared to the standard case. The proposed time multiplexing technique is theoretically analyzed and the results are experimentally verified. A SNR improvement of 11.6 dB is demonstrated experimentally with 3.3 fold time multiplexing. These results open new possibilities in SNR improvement and/or recording speed of EOM-based multi-comb spectroscopic techniques.