Junfeng Song, Xianshu Luo, Xiaoguang Tu, Lianxi Jia, Qing Fang, Tsung-Yang Liow, Mingbin Yu, and Guo-Qiang Lo, "Three-dimensional (3D) monolithically integrated photodetector and WDM receiver based on bulk silicon wafer," Opt. Express 22, 19546-19554 (2014) http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-16-19546
Abstract:
We propose a novel three-dimensional (3D) monolithic optoelectronic integration platform. Such platform integrates both electrical and photonic devices in a bulk silicon wafer, which eliminates the high-cost
silicon-on-insulator (SOI) wafer and is more suitable for process requirements of electronic and photonic integrated circuits (ICs). For proof-of-concept, we demonstrate a three-dimensional photodetector and WDM
receiver system. The Ge is grown on a 8-inch bulk silicon wafer while the optical waveguide is defined in a SiN layer which is deposited on top of it, with ~4 μm oxide sandwiched in between. The light is directed to the Ge photodetector from the SiN waveguide vertically by using grating coupler with a Aluminum mirror on top of it. The measured photodetector responsivity is ~0.2 A/W and the 3-dB bandwidth is ~2 GHz. Using such
vertical-coupled photo detector, we demonstrated an 8-channel receiver by integrating a 1 × 8 arrayed waveguide grating (AWG). High-quality optical signal detection with up to 10 Gbit/s data rate is demonstrated, suggesting a 80 Gbit/s throughput. Such receiver can be applied to on-chip optical
interconnect, DRAM interface, and telecommunication systems.