Ciena Corporation
Optically isolated photodiode for high sensitivity application

Abstract:

An integrated silicon-based photo-detection system, fabricated in an integrated silicon based structure on a silicon-on-insulator (SOI) wafer, includes a photodiode fabricated on an isolated area surrounded by a light barrier, where the light barrier is an area where the SOI wafer is removed, an optical waveguide that guides an input signal light into the photodiode, and external electrical traces that the free electron carriers flow into as photocurrent. A method of fabricating an integrated silicon-based photo-detection system in an integrated silicon based structure on a silicon-on-insulator (SOI) wafer, includes performing deep etching to create a light barrier surrounding an isolated area on the SOI wafer, fabricating a photodiode in the isolated area surrounded by the light barrier, fabricating an optical waveguide that guides an input signal light into the photodiode, and wirebonding external electrical traces to connect to the remainder of the integrated silicon based structure.