GAIN DISPERSION INDUCED SUBPICOSECOND PULSE BREAKUP IN A FIBER AND SEMICONDUCTOR-LASER AMPLIFIER COMBINED SYSTEM

We observe pulse breakup for 650-fs pulses propagating through 9 m of optical fiber followed by an InGaAsP amplifier. The pulses are broaden ed by a factor of two, and a second peak appears at about 2 ps after t he main peak. To identify the responsible mechanisms, we solve numeric ally the propagation equations including nonlinear carrier dynamics an d gain dispersion. We attribute the broadening to two photon absorptio n and the breakup to the interplay between linear gain dispersion and frequency chirp in the amplifier. These pulse distortions could impact devices involving fibers and semiconductor amplifiers for high-speed (> 200 Gb/s) optical switching or transmission. (C) 1996 American Inst itute of Physics.