Optical Solitons and Frequency Comb Generation - Abstract

Schmidt, Mark

On the formation of frequency combs in Fourier domain mode-locked (FDML) lasers

Fourier domain mode-locked lasers are broadband tunable light sources with record sweep rates in which a tunable bandpass filter is synchronized with the roundtrip time of the optical field. Recently, an ultra-stable operating regime with a nearly shot-noise limited intensity trace over a sweep bandwidth of more than 100,nm and a repetition rate of 3.2,MHz was experimentally demonstrated featuring a highly coherent output. Beating experiments have additionally shown that a well defined phase relationship between consecutive sweeps exists. We demonstrate a numerical model describing ultra-stable operation in single polarization setups. This model shows excellent agreement with experimental data and is able to reproduce noise patterns in the intensity trace when the laser is operated beyond the ultra-stable regime inducing non-stationary phase fluctuations. In particular, we investigate the sweep to sweep evolution in different operating regimes and discuss the formation of frequency combs in ultra-stable FDML lasers.