Spectral linewidth of multiple quantum well distributed feedback (MQW-DFB) lasers grown by low pressure MOVPE

The authors investigate the dependence of the spectral linewidth of strained MQW-DFB (multiquantum-well distributed-feedback) lasers on device parameters, such as coupling strength and the number of quantum wells. The spectral linewidth of the MQW-DFB lasers is compared to that of a bulk active laser, as well as to that of a novel MQW-DFB laser with a monolithically integrated passive waveguide. The spectral linewidth of the strained MQW lasers was found to be less than that of the bulk active DFB lasers. Further reduction in the spectral linewidth was observed for MQW structures with a fewer number of wells and larger detuning of the Bragg wavelength. However, the monolithically integrated passive waveguide DFB structure was found to improve the spectral linewidth to a greater extent than conventional strained MQW-DFB lasers.<>