| Silicon photonics has attracted extensive attention in both academia and industry in recent years, as an enabling technology to address the exponentially increasing demands for communication bandwidth. It brings state-of-the-art complementary metal-oxide-semiconductor (CMOS) processing technology to the field of photonic integration. The high yield and uniformity of silicon devices make it possible to build complex photonic systems-on-chip in large production volumes. Cutting-edge device performance has been demonstrated on this platform, including high-speed modulators, photodetectors, and passive devices such as the Y-junction, waveguide crossing, and arrayed waveguide gratings. As the device library quickly matures, an integrated laser source for a transmitter remains missing from the design kit.;I demonstrated hybrid external cavity lasers by integrating reflective optical semiconductor amplifiers and silicon photonics chips. The gain chip and silicon chip can be designed and optimized independently, which is a significant advantage compared to bonding an III-V film on top of the silicon chip. Advanced optoelectronics packaging processes can be leveraged for chip alignment. Tunable C-Band (near 1550 nm) lasers with 10 mW on-chip power and less than 220 kHz bandwidth are demonstrated. O-Band lasers (operating near 1310 nm) as well as successful data transmission at 10 Gb/s and 40 Gb/s using the hybrid laser as the light source are also demonstrated. I designed a single cavity, multi wavelength laser by utilizing a quantum dot SOA, Sagnac loop and micro-ring based silicon photonics half cavity. Four lasing peaks with less than 3 dB power non-uniformity were measured, as well as 4 x 10 Gb/s error free data transmission.;In addition to my main focus on RSOA/Silicon external cavity lasers, I propose and demonstrate a novel germanium-assisted grating coupler with low loss on-and-off chip fiber coupling. A coupling efficiency of 76% at 1.55 microm and 40 nm 1 dB optical bandwidth is achieved using FDTD simulation. |
