Abstract

Optical Frequency Combs (OFC) are coherent light sources, emitting a broad spectrum of evenly spaced narrow frequency lines [1]. Dual-Comb Spectroscopy [2] relies on multiheterodyne beat note detection, accessing high spectral resolution, and fast acquisition. The interest of adding a third comb to the system is demonstrated, for example, in the case of four-wave mixing (FWM) [3], enabling to measure time-resolved non-linear spectra. The joint use of three frequency combs requires a high degree of coherence. The current solutions are either to phase-lock three mode-locked lasers [5]. Here we demonstrate the generation of three mutually coherent frequency comb by spatial light multiplexing in a tri-core fiber (see Fig.1 (a-b)) and we exhibit the potential of this light source for FWM spectroscopy.

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