Supermodes of high-repetition-rate passively mode-locked semiconductor lasers

A nonzero alpha parameter changes the symmetry of supermode in high-repetition-rate passively mode-locked semiconductor lasers. The mode-locking range over which the lowest order supermode retains its minimum gain solution decreases. An increase in absorber strength produces downchirped pulses. The use of a nearest-neighbour mode coupling approximation allows explanation of a chirp-free pulse generation and an electrically controlled operation. A steady-state analysis of the lasers is presented.