Directional Emission Triangle and Square Semiconductor Microlasers

Abstract

Semiconductor microcavity lasers with directional emission are important for real applications. Different from the whispering-gallery modes (WGMs) in microdisk, the confined WGMs in triangle and square micro-resonators connected with an output waveguide can still have high Q-factors in some cases. Room temperature continue-wave electrically injected InGaAsP/InP equilateral-triangle-resonator lasers with the side length 10 to 30 µm are fabricated by standard photolithography, inductively coupled plasma (ICP) etching technique combined with wet chemical etching process. The lasers characteristics are measured and analyzed over temperature range 80-300 K. The influences of the output waveguide on the mode Q-factor and the output coupling efficiency for square micro-resonators are numerically simulated by the finite-difference time-domain (FDTD) techniques. In addition, mode coupling between the WGMs and vertical radiation modes in the cladding layer are investigated by 3D FDTD technique for microcavities with vertical semiconductor confinement.