Generating different-rate optical pulses in a dual-wavelength actively mode-locked fiber laser using cascaded fiber Bragg gratings

Abstract

Dual-wavelength operation of an actively mode-locked fiber ring laser generating picosecond pulses was demonstrated by using a cascaded sequence of two fiber Bragg gratings in the laser cavity. By adjusting the distances between the two fiber gratings, simultaneously mode-locked operation of dual-wavelength at different repetition rate could be achieved when the modulation frequency was appropriate. In the experiments, dual-wavelength pulses at about 2GHz latorand 4GHz (when the modulation frequency was about 2GHz) or at about 2.5GHz and 7.5GHz (when the modulation frequency was about 2.5GHz) were simultaneously obtained and each wavelength could be tuned in arrange ofabout 5nm.