SUPERMODES OF HIGH-REPETITION-RATE PASSIVELY MODE-LOCKED SEMICONDUCTOR-LASERS

We present a steady-state analysis of high-repetition-rate passively m ode-locked semiconductor lasers. The analysis includes effects of ampl itude-to-phase coupling in both gain and absorber sections. A many-mod e eigenvalue approach is presented to obtain supermode solutions. Usin g a nearest-neighbor mode coupling approximation, chirp-free pulse gen eration and electrically chirp-controlled operation are explained for the first time. The presence of a nonzero alpha parameter is found to change the symmetry of the supermode and significantly reduce the mode -locking range over which the lowest order supermode remains the minim um gain solution. An increase in absorber strength tends to lead to do wnchirped pulses. The effects of individual laser parameters are consi dered, and agreement with recent experimental results is discussed.