Exploiting Ultralow Loss Multimode Waveguides for Broadband Frequency Combs
Abstract
Low propagation loss in high confinement waveguides is critical for chip‐based nonlinear photonics applications. Sophisticated fabrication processes which yield sub‐nm roughness are generally needed to reduce scattering points at the waveguide interfaces to achieve ultralow propagation loss. Here, ultralow propagation loss is shown by shaping the mode using a highly multimode structure to reduce its overlap with the waveguide interfaces, thus relaxing the fabrication processing requirements. Microresonators with intrinsic quality factors (Q) of 31.8 ± 4.4 million are experimentally demonstrated. Although the microresonators support ten transverse modes only the fundamental mode is excited and no higher order modes are observed when using nonlinear adiabatic bends. A record‐low threshold pump power of 73 µW for parametric oscillation is measured and a broadband, almost octave spanning single‐soliton frequency comb without any signatures of higher order modes in the spectrum spanning from 1097 to 2040 nm (126 THz) is generated in the multimode microresonator. This work provides a design method that can be applied to different material platforms to achieve and use ultrahigh‐Q multimode microresonators.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 06, 2020
- Source ID
- 10.1002/lpor.202000353
Entities
People
- Alexander L. Gaeta
- Chaitanya Joshi
- Jae K. Jang
- Mateus Corato‐Zanarella
- Michal Lipson
- Utsav D. Dave
- Xingchen Ji
Organizations
- Air Force Office of Scientific Research
- Columbia University
- Defense Advanced Research Projects Agency
- National Science Foundation