학술논문
Surface-Normal Ge/SiGe Asymmetric Fabry–Perot Optical Modulators Fabricated on Silicon Substrates
Document Type
Periodical
Author
Source
Journal of Lightwave Technology J. Lightwave Technol. Lightwave Technology, Journal of. 31(24):3995-4003 Dec, 2013
Subject
Language
ISSN
0733-8724
1558-2213
1558-2213
Abstract
We demonstrate the first vertical-incidence Ge/SiGe quantum well reflection modulators fabricated entirely on standard silicon substrates. These modulators could help enable massively parallel, free-space optical interconnects to silicon chips. An asymmetric Fabry–Perot resonant cavity is formed around the quantum well region by alkaline etching the backside of the Si substrate to leave suspended SiGe membranes, upon which high-index-contrast Bragg mirrors are deposited. Electroabsorption and electrorefraction both contribute to the reflectance modulation. The devices exhibit greater than 10 dB extinction ratio with low insertion loss of 1.3 dB. High-speed modulation with a 3 dB bandwidth of 4 GHz is demonstrated. The moderate-Q cavity ( ${\bf Q \sim 600}$ ) yields an operating bandwidth of more than 1 nm and permits operation without active thermal stabilization.