High-Speed Reconfigurable Free-Space Card-to-Card Optical Interconnects

A reconfigurable free-space-based card-to-card optical interconnect architecture employing MEMS-based steering mirror arrays in conjunction with VCSEL and photodiode arrays is proposed and demonstrated in this paper. Theoretical studies and simulations indicate that error-free [bit error rate (BER) of <; 10^-6] optical interconnects with a range on the order of tens of centimeters can be achieved, and the major factors limiting the performance are the VCSEL beam divergence and interchannel optical crosstalk. The tradeoff between the BER performance and the channel spacing of the receiver MEMS mirror array is also investigated. A proof-of-concept 3 × 10 Gb/s reconfigurable optical interconnect architecture is developed, demonstrating a BER of ~10^-6 and a receiver sensitivity better than ~ -11.5 dBm. Both the port-to-port and board-to-board reconfigurability of the proposed architecture are also experimentally demonstrated, opening the way for attaining higher throughputs through highly dense 3-D parallel optical interconnects.