Silicon optical bench for high-speed optical subassemblies

A passively aligned, flip-chip receiver optical subassembly (ROSA) was developed. The design features a silicon v-groove with a metallized reflector and a photodiode with an offset active area. This design minimizes the optical path length, allowing for much smaller photodetector areas than those used in previous designs. Excellent performance in terms of coupling efficiency, small signal bandwidth and 10 Gb/s eye diagrams for detectors as small as 20 urn in diameter are described. Mechanical features on the bench included special structures for optical underfill, fiber attachment and strain relief.