WDM Receiver Optical Subassembly and Photodetectors for High-Speed Ruggedized Environments

Ultra-high bandwidth ruggedized optical interconnects are critical to flight platforms where they provide small size, low power, and EMI-immune connectivity. However, standard commercial transceivers do not provide for required wide operating temperatures or sufficient ruggedization for the high reliability required in these mission-critical data links. Previous efforts to improve the interconnect bandwidth for harsh environments in flight platforms have focused primarily on using separate optical fibers for each data lane. However, these system configurations use ribbon fibers or fiber bundles, which leads to an increase in cable and connector cost, higher weight, and increased size. The multiples fibers can also be a particular challenge both for high-density on-board connectivity and through bulkheads. Size, weight, and power (SWaP) can be reduced in optical interconnects through the use of wavelength division multiplexing (WDM), where each individual channel utilizes a different wavelength, allowing simultaneous transmission of multiple channels within a single fiber. WDM solutions greatly reduce the SWaP for a fiber optical cable solution, but do require the multiplexing and demultiplexing of the optical channels at the transmitter and receiver, respectively. Typical commercially-available WDM transceivers do not support the wide operating temperature range or environmental ruggedization required for NAVAIR flight platforms. This effort will focus on the design of robust photodetectors and a flexible WDM receiver platform for wide-temperature range, high-speed operation in ruggedized environments. The photodetector and receiver subassembly will be based on a common WDM platform, targeting a single configuration to support between 1 and 4 receiver channels. This will allow for common optical coupling of 50Ąm fiber, either through pigtailed or connectorized interfaces for the targeted configurations of 4x10G, 2x20G, 4x25G, 1x50G, 2x50G and 1x100G. Basing the design around this common receiver platform will allow a wide range of subsystems and flight platforms to integrate this design without requiring a costly redesign and qualification for each variation. The common platform will also minimize the changes needed on the manufacturing line in the production phase, which will reduce the cost of the digital fiber optic receiver subassembly.