High-Power Single Longitudinal Mode Operation of Distributed Feedback Laser Diodes with a Decoupled Confinement Heterostructure

Abstract

A new design of a real-index-guided Distributed Feedback Laser Diode (DFB-LD) based on a Decoupled Confinement Heterostructure (DCH) has been proposed and characteristics of a high power single longitudinal and lateral mode operation have been investigated. A grating was located at the interface under current blocking layer embedded in GaAs waveguide, so that current injection path was kept free from contamination during fabrication processes. A single longitudinal and lateral mode operation up to 400 mW has been achieved at 25°C, CW condition. Oscillation wavelength was around 978 nm and its temperature dependence was 0.087 nm/K. With increasing output power, oscillating longitudinal mode shifts moderately (0.0023 nm/mW) to longer wavelength undergoing a few mode hops. Specific features of DCH such as low thermal and electrical resistance and low gain coupling coefficient may contribute to suppression of thermal disturbance and hole-burning effect, and thus lead to an extremely high power single mode operation.