Fabrication and characterization of InGaAlP/InGaP semiconductor circular ring lasers

We report the fabrication of a semiconductor circular ring lasers based on an InGaAlP/InGaP graded-index separate confinement heterostructure (GRIN-SCH) which attracted much attention for light sources in optical information processing systems such as a laser printer, compact disk player and optical link system. The dimensions of the circular ring cavity are 100 μm–250 μm in diameter, 5–10 μm width of the ridge waveguide, and a Y junction output coupler of 250 μm in length. An ultraviolet (UV) laser-assisted etching process and the two-layer photolithography process were developed for the fabrication of the circular ring cavity. The luminescence-current and spectrum characteristics of laser output showed a single-mode output operating at 698 nm and at threshold current about 60 mA. The reports showed that the pattern definition by the combination of UV laser-assisted etching, and the two-layer photolithography process was capable of complex optoelectronic integrated device processing.