Single-fundamental-mode 850 nm surface relief VCSEL

The performance of the oxide-confined surface-relief (SR) structure vertical-cavity surface-emitting laser (VCSEL) is simulated and analyzed by using the three-dimensional finite-difference time-domain (FDTD) method. The impacts of the device structure parameters on the far-field characteristics are researched. A single-fundamental-mode SR VCSEL with an oxide-aperture of 15 mu m is designed and produced. The single-mode power of the VCSEL is 5 mW, the threshold current is 2.5 mA, far-field divergent angles range from 7.8 degrees to 10.8 degrees and the side-mode suppression ratio is over 30 dB. The optical and electrical properties of the device are in agreement with the results of FDTD simulation, which shows that the SR technology can effectively suppress the higher-order-mode lasing, and make the SR VCSEL work in a single mode under a larger oxide aperture.