Analysis of interior degradation of a laser waveguide using an OBIC monitor

We propose a novel optical-beam-induced current (OBIC) measurement technique for detecting the degradation in the interior of a waveguide. This technique uses an incident light with a wavelength longer than that of the band edge of the active layer. An OBIC scan image was obtained at a wavelength of 1.6 μm, which was 50 nm longer than the PL peak wavelength in the active layer of the degraded laser, and the OBIC became sensitive to some degradation when a long distance guided light was used. Furthermore, we confirmed that the degradation mechanism of the t0.5 deterioration property is mainly governed by diffused defects at the waveguide other than those in the vicinity of the AR facet in a DFB laser.