Performance Methodology and Characterization of a Multi-Fiber Expanded Beam Lensed Optical Interconnect

The demand for high performance, cost-effective optical interconnects is driving the need for novel connectors in the optical communication industry. A multi-fiber lensed ferrule has been introduced that addresses backplane and ganged application requirements through the use of molded, expanded beam optics. The new ferrule maintains the same footprint as traditional multi-fiber ferrules, but uses an array of lenses on the front face to expand and collimate up to sixty-four channels simultaneously. The monolithic ferrule uses a hermaphroditic post and hole mating system to eliminate the costs associated with traditional steel alignment pins. The final result is a collimated beam connector system that enables debris insensitive connections for standard multi-mode optical fiber. The implementation of a new connector system requires the development and verification of an accompanying test infrastructure. Theoretical modeling of both expected insertion loss and back-reflection performance is presented, followed by experimental data to validate the model's assumptions. The elimination of a traditional physical contact connection changes the impact of Fresnel reflections on reference and test setups, and therefore a modification of the conventional loss testing methodology is presented. Furthermore, a study of deliberate connector exposure to oil and debris confirms the connector insensitivity to contamination. Finally, long-term reliability is established after mated pairs of expanded beam connectors were successfully exposed to a series of environmental and mechanical test sequences; presented data shows an average change of < 0.01 dB after days of thermal aging, humidity exposure, and temperature cycling, along with 1000 consecutive connector matings.