Tunable InGaAsP Lasers for Spectral Measurements of High Bandwidth Fibers

An ultrashort-cavity thin-film laser of InGaAsP, pumped with a mode-locked and Q-switched Nd: YAG laser, has been used as the source and an InGaAs/InP p-i-n photodiode as the detector to demonstrate a system capable of measuring bandwidths of 8.5 GHz in single-mode optical fibers. The film laser emits pulses shorter than 10 ps and is tunable over 1700 A near the chromatic dispersion minimum in fibers.