Widely-tunable and ultra-stable hybrid-integrated diode lasers

This thesis describes our investigation into diode lasers based on hybrid integration with frequency-selective waveguide feedback circuits. Deploying intra-cavity ring resonators as feedback filters, implemented using low-loss Si3N4 waveguides, enables single-mode laser operation with wavelength tunability over very wide ranges. Using high-Q ring resonators for cavity length extension is also very effective for improving the laser’s short-term frequency stability, which shows as an ultra-narrow intrinsic (Schawlow-Townes) linewidth. We demonstrate in this thesis that these lasers are also continuously tunable, that the spectral coverage can be extended from the infrared to the visible range, and that these lasers can be frequency locked to optical references to greatly enhance their long-term frequency stability.