External-cavity, actively mode-locked grating-coupled surface-emitting laser and amplification characteristics of a grating-coupled semiconductor optical amplifier

An external-cavity, actively mode-locked grating-coupled surface-emitting semiconductor laser (GCSEL) is demonstrated for the first time to the authors' knowledge. The mode-locked oscillator generates a train of optical pulses at a 297-MHz pulse-repetition frequency. The optical pulse from the oscillator has a width of 22.6 ps and a spectral bandwidth of 0.07 nm at 975.9 nm, giving a time-bandwidth product of 0.50. In addition, amplification characteristics of a grating-coupled semiconductor optical amplifier are studied with a continuous-wave external-cavity GCSEL.