Power spectrum of directly modulated single-mode semiconductor lasers: Chirp-induced fine structure.
01 January 1985
The time-averaged power spectrum of a single-mode semiconductor laser under direct intensity modulation is calculated using the small-signal analysis of the stochastic rate equations. The general formalism includes the effect of frequency chirp owing to current modulation as well as the effect of phase diffusion due to spontaneous emission. The theory explains reasonably well the reported experimental observations. At the same time it provides physical insight in the dynamic process of frequency chirping and its relation to the frequency modulation.