Fourier synthesis of 9.6-GHz optical-pulse trains by phase locking of three continuous-wave semiconductor lasers

Fourier synthesis of optical-pulse trains based on optical phase locking of three cw semiconductor lasers has been demonstrated by use of a semiconductor optical amplifier as a four-wave mixer. The temporal waveforms of the pulse trains were directly observed at a repetition rate of 9.6 GHz by a fast sampling oscilloscope. The FM sideband heterodyne technique was employed to realize a stable homodyne optical phase-locked loop.