Intermodulation distortion in a directly modulated semiconductor injection laser

Abstract

A most important quantity in high‐frequency analog transmission is the intermodulation distortion product. Experimental studies of the third order intermodulation distortion products in the modulation response of high‐speed semiconductor lasers give very low values (<−60 dB) at low frequencies, an increase at a rate of 40 dB/dec as the modulation frequency is increased, and a leveling off at one‐half of the relaxation oscillation resonance frequency. These experimental results can be well explained by a theory based on a perturbative analysis of laser dynamics.