WAVELENGTH-TUNABLE SEMICONDUCTOR LASER AND FABRICATION PROCESS THEREOF

摘要

A wavelength-tunable semiconductor laser comprises an active region including an active layer generating an optical gain by injection of a current, a phase-control region including a tuning layer generating variation of a refraction index by injection of the current, and a distributed-Bragg-reflector region including a tuning layer generating variation of a refraction index by injection of the current. The active region, the phase-control region and the distributed-Bragg-reflector region are arranged in alignment in a resonance direction. A diffraction grating is provided in the vicinity of the tuning layer of the distributed-Bragg-reflector region. The wavelength-tunable semiconductor laser includes means for uniformly injecting a second current to the phase-control region and the distributed-Bragg-reflector region. An optical-confinement factor to the tuning layer of the phase-control region is greater than an optical-confinement factor to the tuning layer of the distributed-Bragg-reflector type.