On low-power semiconductor laser design

Design relations are given for semiconductor lasers having both an active and a passive (low-loss) region within a single resonant cavity. Langevin noise sources are included to make possible the calculation of line width and power fluctuations using Monte Carlo techniques. Explicit relations based on equilibrium conditions are given for line width, power fluctuations, transient-response time constant and side mode level. It is shown by example that when the passive section is several times the length of the active section, the statistics of the power fluctuations become more nearly Gaussian and mode partition noise should become far less noticeable.