1550-nm single-mode grating-outcoupled surface emitting lasers

Single-frequency grating outcoupled surface emitting (GSE) semiconductor lasers emitting at 1550 nm with output powers exceeding 1.6 mW into a multi-mode fiber, threshold currents below 25 mA and with > 30 dB side-mode suppression ratios are reported. These lasers consist of a 500 μm long horizontal cavity, and a 10 μm long second-order outcoupler grating sandwiched between 250 μm long first-order distributed Bragg reflector (DBRs) gratings. Higher output powers can be achieved with longer outcoupler gratings. These GSE lasers operate at 2.5 Gbps and have a full-width at half-maximum (FWHM) beam divergence of 5 x 9 degrees.