Assembly and electrical wiring technologies on planar lightwave circuit (PLC) platform providing hybrid integration of optoelectronic devices and integrated circuits (ICs)

Optoelectronic hybrid integration is a promising technology for realizing the optical components needed in optical transmission, switching, and interconnection systems that use wavelength division multiplexing (WDM) and time division multiplexing (TDM). We have already developed versatile optical hybrid integrated modules using a silica-based planar lightwave circuit (PLC) platform. However, these modules consist solely of the optoelectronic semiconductor devices such as laser diodes (LDs) and photo diodes (PDs) and monolithic optoelectronic integrated circuits (OEICs). To carry out high-speed and versatile electric signal processing functions in future network systems, it is necessary to install semiconductor electrical integrated circuits (ICs) on a PLC platform. In this paper, we describe novel technologies for high-speed PLC platforms which make it possible to assemble both ICs and optoelectronic devices. Using these technologies, we fabricated a two-channel hybrid integrated optical transmitter module which is hybrid integrated with an LD array chip and an LD driver IC. On this PLC platform, we use microstrip lines (MSLs) to drive the LD driver IC. We also considered the effect of heat interference on the LD array chip caused by the LD driver IC when designing the layout of the chip assembly region. The LD array chip and the LD driver IC were flip-chip bonded with solder bumps of a different material to avoid any deterioration in the coupling efficiency of the LD array chip. The optical transmitter module we fabricated operated successfully at 9 Gbit/s non-return-zero (NRZ) signal. This approach using a PLC platform for the hybrid integration of an LD array chip and an LD driver IC will carry forward the development of high-speed optoelectronic modules with both optical and electrical signal processing functions.