Effect of carrier heating on chirp and modulation response of directly modulated semiconductor laser diodes

This paper examines the effect of carrier heating due to hot carrier inject ion in directly modulated semiconductor laser diodes. Using a single-mode r ate equation model including an equation for the energy stored in the condu ction band carriers, the changes in carrier temperature due to hot carrier injection from the barrier layer in quantum-well laser diodes are seen to c ause a degradation in the device's sinusoidal modulation response. This deg radation is coupled with an increase in the wavelength chirp of the light o utput. It is concluded that in order to minimize the detrimental effect of carrier heating on directly modulated quantum well laser diodes the barrier height should be kept as small as practical. Additionally, the appreciable change in device performance brought about by carrier heating should be ac counted for when modelling such devices.