On-Chip Photonic Crystal Surface-Emitting Membrane Lasers

Abstract

Photonic crystal lasers can be realized either based on photonic bandgap defect mode or defect-free bandedge mode, while the bandgap is not essential for the latter. We review here defect-free bandedge mode based photonic crystal surface-emitting lasers (PCSELs) for on-chip integration. We first discuss ultra-thin membrane reflector vertical-cavity surface-emitting lasers (MR-VCSELs), where single layer photonic crystal slabs can be designed as a broadband membrane reflector. Later, we discuss another type of defect-free PCSELs where the lasing cavity is formed based on evanescent coupling of gain medium with the photonic crystal bandedge mode near bandedge. Cavity designs were carried out for the optimal modal overlap and high confinement factors. Lateral cavity size scaling was also investigated both theoretically and experimentally in PCSELs. Buried tunnel junction based InGaAsP quantum well heterostructures were also designed and incorporated into electrically injected PCSELs. Finally, discussions are given toward energy efficient lasers.