Interior Degradation Analysis of Distributed Feedback Laser Using Optical-Beam-Induced Current

We propose a novel optical-beam-induced current (OBIC) measurement technique to detect the degradation of the interior of a laser waveguide. OBIC topographies were obtained with incident transverse-magnetic-mode light, such that OBIC became sensitive to interior degradation. We additionally used transverse-magnetic-mode and transverse-electric-mode lights to confirm that the degradation region of
$t^{0.5}$
deterioration is mainly located in the active layer, not in the vicinity of the antireflection facet.