Abstract

Coherent frequency conversion processes for frequency combs (FCs) are intensively studied as they inter alia enable the use of FCs for precision spectroscopy in the important mid-infrared (MIR) spectral region not covered by laser gain media. Difference frequency generation (DFG) is one promising approach for a simple and robust scheme to generate phase-stable MIR FCs. When used in a spectroscopy experiment, relative intensity noise (RIN) constitutes a major obstacle to achieve high signal-to-noise ratios (SNR) and long averaging times but only a very limited numbers of studies address this issue [1-3]. In this contribution, we report on RIN studies of a DFG MIR source. We found a strong dependence of the MIR idler noise on the delay between pump and signal field. A dither-lock technique was implemented to enable long-term stable and low-noise operation.

© 2017 IEEE