An analytic model for the modulation response of buried heterostructure lasers

This paper describes an analytic model for the modulation response of buried heterostructure (BH) semiconductor lasers. Using a space-averaged carrier density approach, explicit expressions that take into account the combined effects of carrier diffusion and spontaneous emission are derived for the transient decay time of the relaxation oscillations, and the small-signal modulation response for the carriers and photons. The dynamic shift of the lasing wavelength is estimated by calculating the fluctuations of the carrier density during small-signal modulation. Using the analytic solutions obtained, a network synthesis approach is used to derive two-port circuit models for the device. The validity of the theoretical model is verified by comparing the modulation characteristics of a BH laser measured experimentally to that simulated by circuit analysis.