1310-nm asymmetric single mode grating-outcoupled surface-emitting semiconductor laser with a broadband and a narrowband DBR reflector

Abstract

A 1310 nm single-frequency grating-outcoupled surface-emitting (GSE) semiconductor laser with output slope efficiency exceeding 0.05 mW/mA into a multimode fiber, threshold current below 20mA and > 30dB side-mode suppression ratio is reported. The GSE laser consists of a 500μm long active ridge that excites one end of a surface emitting second-order (outcoupler) grating with a broadband reflector terminating the laser cavity at the end of the outcoupler. At the opposite end of the outcoupler is a 200μm long first order distributed Bragg reflector (DBR). The emitting output aperture is approximately 10μm in length. Higher output power is possible for outcoupler lengths greater than 10 um. The GSE laser has an open eye pattern for a nonreturn-to-zero signal at 2.5 Gb/s into a single mode fiber. The far-field beam divergence measured at full-width half-maximum (FWHM) is 5 x 8 degrees.