Regenerative polymeric bus architecture for board-level optical interconnects

Abstract

A scalable multi-channel optical regenerative bus architecture based on the use of polymer waveguides is presented for the first time. The architecture offers high-speed interconnection between electrical cards allowing regenerative bus extension with multiple segments and therefore connection of an arbitrary number of cards onto the bus. In a proof-of-principle demonstration, a 4-channel 3-card polymeric bus module is designed and fabricated on standard FR4 substrates. Low insertion losses (≤ -15 dB) and low crosstalk values (< -30 dB) are achieved for the fabricated samples while better than ± 6 µm -1 dB alignment tolerances are obtained. 10 Gb/s data communication with a bit-error-rate (BER) lower than 10(-12) is demonstrated for the first time between card interfaces on two different bus modules using a prototype 3R regenerator.

Compact Multimode Polymer Waveguide Bends for Board-Level Optical Interconnects

“…Examples of passive interconnection schemes for the formation of optical backplanes include meshed waveguide architectures [12], and optical bus topologies [15], [16]. Key waveguide components for the formation of such complex on-board optical layouts include multimode waveguide bends, crossings, power splitters and combiners.…”

“…As a result, waveguide bends constitute one of the largest space-consuming components in board-level topologies, preventing the formation of more compact on-board waveguide layouts. For example, the recently-demonstrated one Tb/s-capacity 10-card optical backplane [12] and the 4-channel 3-card polymeric optical bus modules [16], both utilise 90 waveguide bends with a radius of 9 mm, while the mid-board optical backplane reported in [10] deploys 17 mm bends. In this paper, therefore, we present a bend design with improved optical performance enabling reduced minimum bending radii for multimode waveguide bends in board-level optical interconnects.…”

A polymer waveguide-based 40 Gb/s optical bus backplane for board-level optical interconnects

“…Various optical backplane systems deploying polymer waveguides have been demonstrated in recent years featuring different types of polymer materials, system designs and interconnection architectures, and making use of various fabrications methods to achieve cost-effective on-board opto-electronic integration. The optical interconnection layer of these systems uses point-to-point links or broadcast architectures which are implemented with large parallel or meshed waveguide arrays [10][11][12][13] and optical bus topologies [14][15][16] respectively. Large parallel waveguide arrays enable the formation of cost-effective board-level interconnects with high aggregate capacities, while meshed waveguide architectures further allow optical interconnection in complex on-board topologies.…”

“…We have recently proposed the use of a regenerative shared bus architecture based on the use of polymer multimode waveguides [15]. The proposed interconnection architecture is distinctively different from other reported board-level optical busses [14,16,17] as it enables the connection of an arbitrary number of cards to the bus and features a waveguide layout which is scalable to larger channel counts [15].…”

“…The proposed interconnection architecture is distinctively different from other reported board-level optical busses [14,16,17] as it enables the connection of an arbitrary number of cards to the bus and features a waveguide layout which is scalable to larger channel counts [15]. In this paper, we present a 40 Gb/s optical backplane demonstrator system based on the use of the regenerative shared bus architecture and PCB-integrated polymer waveguides.…”