Reduced divergence angle of photonic crystal vertical-cavity surface-emitting laser

The reduced divergence angle of the photonic crystal vertical-cavity surface-emitting laser (PC-VCSEL) was investigated in both theory and experiment. The photonic crystal waveguide possessed the weakly guiding waveguide characteristic, which accounted for the reduction of the divergence angle. The three-dimensional finite-difference time-domain method was used to simulate the designed PC-VCSEL, and a calculated divergence angle of 5.2 degrees was obtained. The measured divergence angles of our fabricated PC-VCSEL were between 5.1 degrees and 5.5 degrees over the entire drive current range, consistent with the numerical results. This is the lowest divergence angle of the fabricated PC-VCSEL ever reported.

Chinese National Key Basic Research Special Fund/CNKBRSF 2006CB921700 National Natural Science Foundation of China 10634080 6067704660838003National High Technology Research and Development Program of China 2006AA03Z403 This work is supported by the Chinese National Key Basic Research Special Fund/CNKBRSF (Grant No. 2006CB921700), the National Natural Science Foundation of China (Grant Nos. 10634080, 60677046, and 60838003), and the National High Technology Research and Development Program of China (Grant No. 2006AA03Z403).