SOA fiber laser mode-locked by gain modulation

This work reports, for the first time to our knowledge, on an experimental and theoretical study of mode locking via synchronous pumping of a semiconductor optical amplifier (SOA) used as the active medium of a fiber laser. SOA modulation with injection current pulses having duration of 1.2 mu s and repetition rate equal to that of the fundamental intermode frequency spacing of the cavity (84.9 kHz) led to generation of mode-locked pulses with duration of 650 ns at a wavelength of 1.54 mu m. The feasibility of the proposed method and the basic parameters of the generated pulses are corroborated by numerical modeling. The key advantages of the proposed laser are simplicity of implementation, comparatively high efficiency, spectral universality, and possibility of pulse shape control. (C) 2018 Optical Society of America