Multi-chip hybrid integration on PLC platform using passive alignment technique

A multi-chip hybrid integration technique on a planar lightwave circuit (PLC) platform achieves bonding accuracy of better than 1.0 μm and adequate bonding strength. This procedure consists of a chip-by-chip alignment step and a simultaneous solder reflowing step. In the chip-by-chip assembly step, opto-electronic chips were successively placed at their optimum positions by passive alignment while keeping the platform temperature below the solder melting point. In the solder reflowing step, all chips were bonded simultaneously by reflowing the solder. This procedure was used to Fabricate a transceiver module consisting of a Y-branch PLC and three optical devices: a spot-size converted laser diode as a transmitter, a monitor photodetector, and a waveguide photodetector as a receiver. These chips were integrated in a small area of only 1.3 mm×2.0 mm with an accuracy of 1.0 μm. This demonstrates the potential of this procedure for fabricating highly functional and low-cost optical modules