Single-mode surface-emitting DFB lasers with a large-area oxidized aperture based on the surface grating

We propose and experimentally demonstrate an 850 nm single-mode surface-emitting distributed feedback laser based on the surface grating. The laser composes a second-order grating section sandwiched by two first-order grating sections. The second-order grating provides not only surface emission, but also phase shift to remove the emission degeneracy. A high side-mode suppression ratio of 47 dB has been achieved. By employing a large-area rectangle-shaped oxidized aperture, a low threshold current of 1.8 mA and a low differential resistance of 59 Ω are successfully achieved in a horizontal-cavity surface-emitting laser.