High temperature continuous-wave (CW) operation of 1310-nm single-frequency grating-outcoupled surface emitting (GSE) semiconductor lasers with output powers exceeding 3.0 mW into a multi-mode fiber, threshold currents below 30 mA and with > 30dB side-mode suppression ratios at temperatures of up to 85 C are reported. These lasers consist of a 400 µm long horizontal cavity, and a 15 µm long second-order outcoupler grating sandwiched between 200 µm long first-order distributed Bragg reflector (DBRs) gratings. Higher output powers can be achieved with longer outcoupler gratings. These GSE lasers operate at 3.125 Gbps and have a full-width at half-maximum (FWHM) beam divergence of 7 x 13 degrees.