Surface-Grating Distributed Bragg Reflector Lasers with Deeply Etched Grooves Formed by Reactive Beam Etching

Abstract

Two surface-grating distributed Bragg reflector (DBR) lasers, one using a 1.55-µm-wavelength InP-based material system and one using a 0.98-µm-wavelength GaAs/AlGaAs material system, were made using the same reactive beam etching technique following single-step growth of the layer structure for the lasers. A 800-nm-deep grooved grating with a 240 nm period for 1.55-µm-wavelength first-order diffraction and one with a 150 nm period for 0.98-µm-wavelength first-order diffraction were formed using electron-beam lithography and Br2-N2 mixed-gas reactive beam etching. Single-longitudinal-mode operation with a side-mode suppression ratio of over 27 dB was obtained for both lasers; the output power was more than 15 mW for the 0.98-µm one. Between 15 and 55°C, the measured temperature dependence of the lasing wavelength for both lasers was about 0.1 nm/°C, which is one-fifth of the dependence of a Fabry-Perot-type laser. The performance of these lasers indicates the wide applicability of the present etching technique to the fabrication of various wavelength-selective devices.