Analysis of Optical-Injected Distributed Feedback Lasers Using Complex Optical Low-Coherence Reflectometry

Optical-injected distributed feedback (DFB) semiconductor lasers were analyzed using a phase-controlled high-resolution optical low-coherence reflectometer (OLCR). The effective group refractive index and its variation above the threshold, the cavity internal loss, and the grating coupling factor of a multiquantum-well DFB lasers were also obtained. The direct measurements of the injection-induced complex-modal index changes were also presented. The OLCR technique was found to be an effective method for determining active device parameters such as the linewidth enhancement factor or the grating coupling coefficient that was earlier accessible only by measurements coming from separate optical setups.