Asymmetrical Longitudinal Mode Spectrum of Fabry-Perot Semiconductor Lasers

Abstract

Quantitative analysis has been given to account some asymmetric features observed on the mode spectrum of the F-P semiconductor lasers detected at the end facets of the diodes. Using ray trace method, the spontaneous emission spectrum generated by the illuminating centers inside the diode has been extracted from the mode spectrum obtained at the end facet. After the wavelength difference between the peaks of the gain and spontaneous emission has been experimentally determined, the output powers P p and P v at the resonant and antiresonant wavelengths of the mode and the asymmetric distribution of the modulation index on the output spectrum have been studied. Employing the implicit analytical solutions to the multimode rate equations, the variation of the mode intensity with wavelength has been simulated. The theory predicts that the mode intensity is larger at the shorter wavelength side than that at the longer wavelength side, and the experiments have quantitatively confirmed this conclusion.