Heterogeneous Integration of III-V Semiconductor Compounds on Silicon for Functional Photonic Circuits

There has been extensive research in realizing large-scale integration of silicon (Si) photonics for long-haul communications, high-throughput optical interconnects, and future high performance computing (HPC). The impetus for this research lies in the fact that the silicon-on-insulator (SOI) platform is fully compatible with CMOS technology which drives mature IC technology and allows for a convergence with large-scale integrated photonics. Recent advances in key components such as high-contrast, low-loss arrayed waveguide gratings/routers (AWG/AWGR), high speed optical modulators, germanium photo-detectors, and single-wavelength hybrid silicon laser sources have all paved a path towards realizing large chip-scale optical systems with various functionalities. Recently, the energy efficiency of these photonic components in an optical link have drawn strong attention with some projections indicating by 2020, the energy consumption of most components in 100-gigabit-per-second (Gbps) systems will be between a few pico-Joules (pJ) and sub-pJ per bit. Therefore, over the past few years, there has been keen interest in heterogeneous integration of III-V compounds with silicon to realize monolithic integration of efficient hybrid devices.;This dissertation pursues the systematic development of passive silicon photonics and III-V InP/InGaAsP photonics to realize III-V/Si heterogeneous integration. Heavy emphasis is placed on optimizing the design and fabrication of the silicon photonics platform for optical routing as well as the III-V platform for optical gain functionality. Along the way, novel devices are developed such as high contrast and high resolution arrayed waveguide gratings (AWG) for optical mux/demux, continuous wave (CW) laser sources, and low repetition rate mode-locked lasers for on-chip frequency combs. In the end, this work culminates in the fabrication, design, and characterization of a hybrid III-V/Si platform via hydrophilic wafer-bonding that allows for the realization of semiconductor lasers and record efficiency III-V/Si optical amplifiers on a silicon substrate. We discuss the design and demonstration of highly efficient 1.55 mum hybrid III-V/Silicon semiconductor optical amplifiers (SOA). The optimized III-V wafer stack consists of Al0.10In0.71Ga 0.18As multiple quantum wells (MQW) and Al0.48In0.52 As electron stop layers to realize SOAs with high wall-plug efficiency (WPE). We present various designs and experimentally determine WPE values for 2 mW and 0.1 mW input power amplification. The 400 mum long flared SOA achieved the highest WPE value of 12.1% for output power > 10mW and the 400 mum long straight SOA achieved the highest WPE value of 7.3% for output power < 10mW.