Novel trace design for high data-rate multi-channel optical transceiver assembled using flip-chip bonding

We propose a trace design for high data-rate multichannel optical transceiver assembled using flip-chip bonding technology. The trace, which is formed on a transceiver substrate, compensates for bandwidth degradation due to the parasitic capacitance of the flip-chip bonding pad for optical and electrical devices. The trace was adopted to the receiver side of a flexible-printed-circuit-based optical engine that consists of a 25-μm-thick flexible printed circuit substrate on which a vertical-cavity surface-emitting laser array, driver, photodiode array, and transimpedance amplifier are mounted by flip-chip bonding. The polymer waveguide is laminated from the backside of the substrate via microlens-imprinted film for optical coupling. The sensitivity degradation caused by the parasitic capacitance was successfully suppressed to 0.6 dB at 40 Gb/s by using our trace design compared to that with a minimum length wire bonding connection.