Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences


UC Berkeley


Research Projects

Nano Electro-Mechanical Optoelectronic (NEMO) Tunable VCSEL

Christopher Chase, Constance Chang-Hasnain and Yi Rao

Defense Advanced Research Projects Agency HR0011-04-1-0040

Optical micro-electromechanical mirrors are the key enabling technology for the dynamic processing of optical signals. They are often utilized for reconfiguring the signal path in an optical switch, or for tuning the length of a laser's cavity and its output wavelength. A wavelength-tunable laser can be constructed by combining an optical MEMS mirror with a vertical-cavity surface-emitting laser (VCSEL). However, the requirement for distributed Bragg reflectors (DBRs) imposes a significant limitation on the tuning speed, wavelength range, power consumption, as well as fabrication difficulties. In this work, we present a nano electro-mechanical optoelectonic (NEMO) tunable laser utilizing the combination of a VCSEL and mobile, lightweight mirror based on a single-layer, high-contrast subwavelength grating (HCG). The HCG reflector enables the shrinking of the mechanical device in thickness and length, which leads to significant reduction of the mass and increase of the mechanical resonant frequency. This allows for a wavelength-tunable light source with potentially tens-to-hundred nanosecond range switching speed and suggests new applications in sensing and displays.

Figure 1
Figure 1: Schematic of a nano electro-mechanical optoelectronic tunable VCSEL

Y. Zhou, M.C.Y. Huang and C. J. Chang-Hasnain, “Tunable VCSEL with Ultra-Thin High Contrast Grating for High-Speed Tuning “, Optics Express (2008)
M.C.Y. Huang, Y. Zhou and C.J. Chang-Hasnain, “A nanoelectromechanical tunable laser,” Nature Photonics, 2, 180 - 184 (2008)
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, pp. 119-122 (2007)
Christopher Chase, Ye Zhou, and Connie J. Chang-Hasnain, "Size effect of high contrast gratings in VCSELs," Opt. Express 17, 24002-24007 (2009)
2) W. Hofmann, C. Chase, M. Müller, Y. Rao, C. Grasse, G. Böhm, M.-C. Amann, C. J. Chang-Hasnain, "Long-Wavelength High-Contrast Grating Vertical-Cavity Surface-Emitting Laser," IEEE Photonics Journal, vol. 2, no. 3, pp.415-422 (2010).
1) C. Chase, Y. Rao, W. Hofmann, and C. J. Chang-Hasnain, "1550 nm high contrast grating VCSEL," Opt. Express 18, 15461-15466 (2010).