Dominic Goodwill

Free space optical interconnect at 1.25 Gb/s/channel using adaptive alignment

Free space optical backplanes have previously required precision mechanics or moving parts. An adaptive alignment technique is described, using redundant VCSEL and detector arrays for real-time mapping of parallel 1.25 Gb/s data channels to aligned links.

Tri-layer silicon nitride-on-silicon photonic platform for ultra-low-loss crossings and interlayer transitions

We present a three-layer silicon nitride on silicon platform for constructing very large photonic integrated circuits. Efficient interlayer transitions are enabled by the close spacing between adjacent layers, while ultra-low-loss crossings are enabled by the large spacing between the topmost and bottommost layers. We demonstrate interlayer taper transitions with losses < 0.15 dB for wavelengths spanning from 1480 nm to 1620 nm. Our overpass waveguide crossings exhibit insertion loss < 2.1 mdB and crosstalk below -56 dB in the wavelength range between 1480 nm and 1620 nm with losses as low as 0.28 mdB. Our platform architecture is suited to meet the demands of large-scale photonic circuits which contain hundreds of crossings.

Optical link for an adaptive redundant free-space interconnect

Board to board free-space optical interconnects can deliver high bandwidth with no physical contact but suffer from poor tolerances to misalignment. In order to obtain high misalignment tolerances, we propose the use of an active alignment scheme in conjunction with an optimized optical design. The active alignment scheme uses a redundant set of optical links and the active selection of the best link. The optical design maximizes the alignment tolerances between the two boards.

A hyperplane smart pixel array for packet based switching

The operation, simulation, and testing of a 4/spl times/2 CMOS-SEED smart pixel array is presented. The smart pixel array discussed implements a hyperplane based ATM switch.

5-Gb/s 2-channel bidirectional adaptive redundant FSOI demonstrator system

A novel board-to-board free space optical interconnect which operates on the principle of redundancy is described. Tolerance to misalignment is achieved through the use of 2D arrays of lasers and detectors together with an adaptive alignment algorithm based on redundant transceivers and a defocused optical interconnect. In this system, four 1.25 Gb/s data channels are supported by transmitter modules and receiver modules (2 per board) which contain 3 X 3 VCSEL and 3 X 3 photodiode arrays, respectively. The system was designed to have lateral misalignment tolerance of +/- 1 mm and angular tolerance of +/- 1 degree(s).