Tunable Two-Color Lasing Emission Based on Fabry-Pérot Laser Diode Combined With External Cavity Feedback

In this paper, two-color lasing emission is experimentally demonstrated by employing a multimode Fabry-Pérot laser diode (MMFP-LD) associated with external cavity of two tunable filters and an erbium-doped fiber amplification (EDFA), whose difference frequency is quasi-continuously tunable from several hundred GHz to more than 2 THz. The obtained side-mode suppression ratio (SMSR) in the output spectrum is around
$\sim$
20 dB, and the modulation depth of simulated beat signal converted by two emission modes rapidly decayed as increasing the frequency separation. In addition, optical behaviors induced by mode competition and four-wave mixing are observed and discussed, while the difference frequency was shortened to GHz regime.