Beam quality study for single-mode oxide-confined and photonic crystal VCSELs

A high-quality single mode beam is desirable for the efficient use of lasers as light sources for optical data communications and interconnects. This work shows a parametric study of the beam quality of vertical-cavity surface-emitting lasers (VCSELs). Using a novel vertical setup we calculated the beam quality factor, M2, from beam radius measurements across the operating range of on-wafer devices. The device operating range is determined from the light-current-voltage measurement. We measured spectral content across the operating range to determine the number of operating modes, with single mode devices being of primary interest, and calculate the root-mean-square linewidths and side-mode suppression-ratio to further quantify the beam quality. We characterized the beam quality of VCSEL devices emitting ≈ 850 nm with oxide-confined apertures of the 2.5 and 5 μm and photonic crystal confinement with varying hole etch depths and b/a ratios. Device characterization and beam quality data for each of the studied devices is presented and discussed.
Vertical cavity surface emitting lasers, Oxides, Photonic crystals, Optical testing
Janice T. Blane, William K. North, Peter R. Zeidler, Jonathan B. Dencker, David B. Chacko, Brian Souhan, Kirk A. Ingold, James J. Raftery Jr., "Beam quality study for single-mode oxide-confined and photonic crystal VCSELs," Proc. SPIE 9766, Vertical-Cavity Surface-Emitting Lasers XX, 97660I (4 March 2016);