Largely detuned injection-locked semiconductor lasers

The equations for a semiconductor laser subject to injection are examined numerically and analytically for large values of the detuning parameter. Our analysis is motivated by recent experimental studies using either distributed feedback laser diodes or vertical-cavity surface-emitting lasers. For negative detuning, we show that a pulsating intensity regime may coexist with a stable steady state. Transitions between time-periodic and steady states as the injection rate is progressively increased or decreased appear through sudden jumps. Of particular interest is the fact that the upper locking point corresponds to a bifurcation point to quasiperiodic intensity oscillations. For positive detuning, the pulsating intensity regime is the only stable state until steady state locking smoothly occurs through a Hopf bifurcation point. Our analysis is based on a new asymptotic analysis of the semiconductor laser equations which allows analytical expressions for all bifurcation points.