Silicon Nitride Microresonators at 1.06 Microns

Optical frequency combs have numerous applications in spectroscopy, metrology, and communications. Silicon nitride microresonators can produce broadband combs with lower cost, smaller physical footprint, and higher repetition rate than current commercial technologies, but most previous work on this platform has been done with pump wavelengths around 1.55 μm. The availability of equipment operating at 1.06 μm makes this an attractive wavelength for expanding the functionality of Si3iN4 resonators. However, comb generation is complicated by stronger normal dispersion, lower quality factors, and waveguide damage at high optical power. This thesis explores device design and experimental methods for navigating these challenges. Waveguide dispersion engineering is investigated using finite element simulation and in practice. Evidence of transverse mode coupling at 1 micron, which can be used to generate normal dispersion combs, is also presented. A free-space pump blocking setup for easier detection of comb power is demonstrated. Finally, thermally-induced tensile strain and the fiber fuse effect are identified as the mechanisms behind high power damage, and suggestions are made for their mitigation