A PACKAGING TECHNIQUE FOR AN OPTICAL 90-DEGREES-HYBRID BALANCED RECEIVER USING A PLANAR LIGHTWAVE CIRCUIT

A new technique has been developed for packaging an optical 90 degrees -hybrid balanced receiver using a planar lightwave circuit (PLC) for t he application to an optical homodyne detection system, This receiver consists of a silica-based PLC as an optical coupler, two polarization beam splitters (PBS's), two GRIN rod lenses to achieve perfect optica l interconnections, two photoreceivers that each have a preamplifier, and twin p-i-n photodiodes (PIN-PD's). The photoreceivers are fabricat ed using microsolder bump bonding to eliminate parasitic elements in t he interconnections between the preamplifiers and the PIN-PD's, An imp edance-matched film carrier technique is used to achieve impedance-mat ched interconnections between the preamplifiers and the ceramic packag es, Experiments showed that a receiver fabricated using this packaging technique has excellent performance: a broad-band frequency response of 14 GHz and, consequently, 10-Gb/s binary phase shift keying (BPSK) homodyne detection.