GaSb-based mid infrared photonic crystal surface emitting lasers

Abstract

We demonstrated for the first time above room temperature (RT) GaSb-based mid-infrared photonic crystal surface emitting lasers (PCSELs). The lasers, under optical pumping, emitted at lambda(lasing) similar to 2.3 mu m, had a temperature insensitive line width of 0.3nm, and a threshold power density (P-th) similar to 0.3KW/cm(2) at RT. Type-I InGaAsSb quantum wells were used as the active region, and the photonic crystal, a square lattice, was fabricated on the surface to provide optical feedback for laser operation and light coupling for surface emission. The PCSELs were operated at temperatures up to 350K with a small wavelength shift rate of 0.21 nm/K. The PCSELs with different air hole depth were studied. The effect of the etched depth on the laser performance was also investigated using numerical simulation based on the coupled-wave theory. Both the laser wavelength and the threshold power decrease as the depth of the PC becomes larger. The calculated results agree well with the experimental findings. (C) 2015 Optical Society of America