Single-Frequency 1310-nm AlGaInAs-InP Grating-Outcoupled Surface-Emitting Lasers

Single-frequency 1310-nm grating-outcoupled surface-emitting (GSE) semiconductor lasers with output slope efficiencies exceeding 0.1 mW/mA into multimode fibers, threshold currents below 22 mA, and >30-dB sidemode suppression ratios are reported. These GSE lasers consist of 500-μm-long active ridges that excite one end of surface-emitting second-order outcoupling gratings with 200-μm-long first-order distributed Bragg reflector gratings terminating the laser cavities at both ends. The grating outcouplers range from 10 to 50 μm in length. These lasers have an open eye pattern for nonreturn-to-zero signals at 2.5 Gb/s into single-mode fibers. The full-width half-maximum far-field beam divergences range from 1.5/spl deg/ × 8/spl deg/ to 5/spl deg/ × 8/spl deg/.