Huei Pei Kuo

A High-Speed Optical Multi-Drop Bus for Computer Interconnections

Buses have historically provided a flexible communications structure in computer systems. However, signal integrity constraints of high-speed electronics have made multi-drop electrical busses infeasible. Instead, we propose an optical data bus for computer interconnections. It has two sets of optical waveguides, one as a fan-out and the other as a fan-in, that are used to interconnect different modules attached to the bus. A master module transmits optical signals which are received by all the slave modules attached to the bus. Each slave module in turn sends data back on the bus to the master module. Arrays of lasers, photodetectors, waveguides, microlenses, beamsplitters and Tx/Rx integrated circuits are used to realize the optical data bus. With 1 mW of laser power, we are able to interconnect 8 different modules at 10 Gb/s per channel. An aggregate bandwidth of over 25 GB/s is achievable with 10 bit wide signaling paths.

A High-Speed Optical Multidrop Bus for Computer Interconnections

Signal integrity constraints of high-speed electronics have made multidrop electrical buses infeasible. This high-speed alternative uses hollow metal waveguides and pellicle beam splitters that interconnect modules attached to the bus. With 1 mw of laser power, the bus can interconnect eight modules at 10 gbps per channel and achieves an aggregate bandwidth of more than 25 gbytes per second with 10-bit-wide signaling paths.

Metal Coated Si Nanograss as Highly Sensitive SERS Sensors

We created novel SERS substrates by metalizing (Ag or Au) Si nanograss fabricated by a Bosch process on single crystalline silicon. We demonstrated that the fabricated SERS substrates are highly sensitive. The sensitivity of the substrates depends on the target molecules, the excitation laser wavelengths and the metal coating on the silicon nanograss. With the optimal excitation condition at 633 nm, an enhancement factor of 6 × 107 can be achieved for trans- 1,2-bis(4-pyridyl)-ethylene (BPE) molecules on the gold coated silicon nanograss substrate.

Telecentric Optics for Free-Space Optical Link

We describe a telecentric optical system for free-space multichannel optical interconnects. The targeted aggregate data rate is 240 Gb/s. We have a unique implementation of telecentric optics and achieved an optical link that is simple, robust and modular. The integrity of the optical link is not significantly degraded with a >plusmn2 mm translational misalignment between the transmitter and receiver arrays. With this optical link, we need only a low bandwidth active servo mechanism to compensate for static tilt and possibly low frequency thermally-driven shift between the transmitter and receiver arrays.