Semiconductor optical amplifier (SOA) packaging for scalable and gain-integrated silicon photonic switching platforms

We report on the design, fabrication, packaging and characterization of a 4-channel semiconductor optical amplifier (SOA) flip-chip mounted on a photonic carrier. Significant loss occurs across high radix silicon photonic switching platforms due to multiple switching stages, waveguide crossings and I/O coupling elements. To overcome these losses, we propose the hybrid integration of a III-V SOA onto a photonic switch carrier to realize a gain neutral switch. Custom four channel cleaved facet SOA variants were designed with unique mounting structures for precise vertical alignment. A photonic carrier test site was designed with unique SiN waveguide coupling structures, vertical reference stops, a trench with metal lines and AuSn solder bumps for device bonding. Individual SOAs were attached to photonic carriers using a precision flip-chip bonder. All assemblies exhibited good bond strength and no line-line shorts were observed. The SOA and assembled test sites were characterized in the 1.5- 1.6 μm wavelength range. A net SOA/photonic carrier optical gain of greater than 10 dB was observed.