Unidirectional-Emission Single-Mode AlGaInAs-InP Microcylinder Lasers

AlGaInAs-InP microcylinder lasers with an output waveguide surrounded by benzocyclobutene are fabricated, using standard photolithography and inductively coupled-plasma etching technique. Room-temperature continuous-wave (CW) operation is realized for a microlaser with a radius of 20 μm and a 2-μm-wide output waveguide. Single-mode operation with side-mode suppression ratio around 25 dB is achieved, and the wavelength shifts from 1563.5 to 1567.3 nm with the injection current increases from 50 to 100 mA. The characteristic temperature of the threshold current is 58 K, obtained by fitting the output power versus the injection current with analytical relations. The practical laser temperature is expected to be about 391 K at the CW injection current of 130 mA.