A Four-Channel Silicon Photonic Carrier with Flip-Chip Integrated Semiconductor Optical Amplifier (SOA) Array Providing >10-dB Gain

Hybrid integration of a 4 -- channel semiconductor optical amplifier array onto a silicon photonic carrier with integrated SiN waveguides has been demonstrated. Custom packaging features are designed into the silicon photonic carrier, including efficient waveguide optical coupling structures, an etched trench with metal lines and AuSn solder pads for SOA integration, and vertical reference stops for precise SOA vertical alignment. Custom 1550-nm SOA arrays with 4 channels at 250-μm pitch providing > 20 dB gain were fabricated. The SOAs incorporate packaging structures designed for flip-chip assembly to the photonic carrier. A 1-μm assembly target was established from optical coupling tolerance measurements. A bonding process was developed to assemble SOA/photonic carrier modules with good bond strength and accurate alignment. Fiber coupling to the assembled modules demonstrated > 10 dB fiber-to-fiber gain over 60-nm bandwidth centered at 1550 nm for all 4 SOA channels. Gain ripple in the optical spectrum was significantly reduced with the incorporation on index-matching optical underfill. High-speed studies showed each SOA channel supports error-free 4-wavelength 25 Gb/s WDM links.