Next-generation, high-density, low-cost, multimode optical backplane interconnect

Abstract

This paper describes the development, termination and performance of next generation optical backplane interconnect components. This low cost, dense optical interconnect technology combined with recent advances in 10G/lane and beyond, miniature imbedded Tx/Rx devices is driving bandwidth density to unprecedented levels. A monolithic, multi-fiber ferule with integrated collimating lenses was designed with the same overall footprint as a traditional MT-type, multi-fiber rectangular ferrule. The new optical ferrule was designed with precision micro holes for alignment to the lens array allowing for incorporation of multiple rows of fibers into single ferrule unit. The design supports up to four rows with as many as 16 fibers per row for a total potential lane count of up to 64 within in a single ferrule. A low cost termination is achieved by securing precision-cleaved fiber arrays into the rear of the ferrule with a quick-cure, index matched, UV light activated epoxy. The elimination of a polished fiber array greatly reduces the cost and complexity associated with physical contact based multi-fiber interconnects. With the same overall footprint as an MT ferrule, the new, lens-based ferrule can be used in conjunction with MPO and other MT based connectors. However, by eliminating the need for physical contact via the use of collimated light beams, the connection force per ferrule required is greatly reduced, paving the way for high ferrule counts and mass insertion of dense optical backplanes. Mated pairs of the new ferrule were tested for insertion loss with the substitution method and all channels were <1dB.