DISTRIBUTED BRAGG REFLECTOR LASER FOR FREQUENCY MODULATION COMMUNICATION SYSTEM

摘要

DISTRIBUTED BRAGG REFLECTOR LASER FORFREQUENCY MODULATED COMMUNICATION SYSTEMSAbstractTo overcome the deleterious effects of the nonuniform frequencymodulation response in semiconductor lasers due to current injection in directfrequency modulation applications, it has been determined that the linewidthenhancement factor a be made as large as possible. In one embodiment, distributedBragg reflector lasers well suited for frequency modulation lightwavecommunication systems are designed to have an integrated feedback element such asa corrugation grating whose effective pitch is selected to cause the Bragg wavelengthand, therefore, the laser operating wavelength to be longer than the wavelength atsubstantially the maximum gain or gain peak in the semiconductor structure. Thatis, the wavelength of the grating is effectively detuned toward the longer wavelengthand lower energy side of the peak of the gain profile. Such detuning increases thelinewidth enhancement factor in such a way that the nonuniform frequencymodulation response and its effects are minimized and, in some cases, substantiallyeliminated.