Design of a compact, high speed optical transceiver using two step overmolding

A low cost, compact optical transceiver has been designed for emerging fiber data distributed interface (FDDI) and fiber channel local-area networks (FCLANs). This transceiver has been designed to meet the growing volumes and rapidly falling prices in the FDDI marketplace. The package is designed to be fully compliant with an industry standard package outline and footprint. This optical data link (ODL) contains a duplex selection combining (SC) connector receptacle-compatible with the ANSI fiber channel and low-cost FDDI standards. With a single row of nine pins, the transceiver will occupy less than 1.0 in² of board space. This ODL transceiver is designed using two-step overmold packaging technology. This technology integrates optical and electrical components in a single, sealed, transfer molded package. This package design uses a copper-based leadframe to provide low-cost interconnection and mass handling. The final assembly sequence was conceived using the latest design for simplicity (DFS) principles. This paper describes the design concept and challenges required to implement a full transceiver in such a small size. Thermal analysis results are discussed. Electrical design issues such as crosstalk and external noise immunity are also described. Initial performance results using preliminary design models will be reported