Ultralow-Loss Silica Resonators and Waveguides on a Silicon

iii For my family, who offered me unconditional love and support throughout the course of my life. iv Acknowledgements Looking back at my years at Caltech, I have immensely enjoyed this most challenging and rewarding experience here. This institute offered me great freedom and a creative environ-ment to explore not only the outside world but also my own interests. I would like to extend my gratitude to all those who made my life at campus rewarding and enjoyable. Firstly, I would like to sincerely thank my advisor, Professor Kerry Vahala, for giving me a wonderful research opportunity and supporting me throughout my graduate studies at Caltech. In spite of his busy schedule, Kerry was always flexible for individual meetings and offering insightful advice and zealous guidance. His brilliance, creativity, optimism, and enthusiasm provided the perfect role model for me. His visionary research ideas encouraged me to exceed my limitations and achieve goals beyond my ability. In addition to that sci