Fiber-compressed high-repetition-rate pulses from a mode-locked GaAs diode laser

A GaAs diode laser (wavelength 800 nm) was actively mode locked in an external cavity that utilized grating feedback or injection seeding to control the optical spectrum of the pulses and hence the laser's frequency chirp. The chirp was large enough and the pulse duration short enough that the pulses could be compressed in single-mode optical fiber. The shortest pulses were compressed to 7 ps at a 4.1-GHz repetition rate in 550 m of optical fiber, with an average output power of 0.3 mW measured after the pulse compressor.