Research Projects

High-Contrast Subwavelength Grating VCSELs with Large Fabrication Tolerance (HCG)

Ye Zhou, Michael Chung-Yi Huang and Constance Chang-Hasnain

High reflective mirrors with broad bandwidths are key components in many optoelectronic devices such as vertical-cavity surface-emitting lasers (VCSELs), optical detectors, and optical filters. Semiconductor-based distributed Bragg reflectors (DBRs) have been widely used as high reflective mirrors. However, due to the material constraints, a large number of DBR pairs are required to achieve high reflectivity, which leads to epitaxy challenges in many material systems. This problem is one of the key bottlenecks for the development of VCSELs and other DBR-based optoelectronic devices in many wavelength regimes such as blue-green and mid-infrared. In addition, high precision in DBR layer thicknesses and compositions (better than 1%) are required in order to achieve high reflectivity. In this project, we present high-contrast subwavelength grating (HCG) integrated VCSELs with large fabrication tolerance. We show that a HCG-based structure can be be implemented by a low-cost and high-throughput fabrication process such as nano-imprinting for large volume batch processing.

Figure 1: HCG integrated VCSEL

[1]

M. C. Y. Huang, Y. Zhou, and C. J. Chang-Hasnain, "A Surface-Emitting Laser Incorporating a High-Index-Contrast Subwavelength Grating," Nature Photonics, Vol. 1, 2007, pp. 119-122.

More information: http://light.eecs.berkeley.edu/cch/HCSWG.html