80-160-GHz mode-locked fiber ring laser synchronized to external optical pulse stream

The authors present a novel scheme to generate ultrahigh repetition rate picosecond pulses synchronized to an optical pulse stream in an actively mode-locked fiber ring laser. A monolithic Mach-Zehnder interferometer with integrated semiconductor optical amplifiers serves as an 80-GHz optically controlled modulator. 80-GHz transform-limited 2.1-ps Gaussian pulse with low timing jitter, extinction ratios up to 25 dB, and 5 mW of average output power are demonstrated. The laser is wavelength tunable over more than 15 nm around 1555 nm. At 160 GHz, 2.5-ps pulse trains with 3-mW output power are generated by rational harmonic mode locking.