Femtosecond Pulse Pairs in Multi-ring CMOS Microresonators
Abstract
Microresonator solitons exist through a balance of optical nonlinearity and dispersion, which must be anomalous for bright soliton generation. Moreover, microresonators must feature high optical Q factors for low pump power operation of the resulting microcomb. While these challenges have been addressed at telecommunications wavelengths using a range of material systems, CMOS-foundry resonators do not yet support bright solitons as their waveguides feature normal dispersion. Furthermore, all resonators are dominated by normal dispersion at shorter wavelengths. For these reasons, there has been keen interest in developing methods to induce anomalous dispersion for bright soliton generation in systems that otherwise feature normal dispersion. We have recently engineered anomalous dispersion in CMOS-foundry resonators by partially-coupling resonators. This geometry introduces unusual new features to bright soliton generation. For example, spectra resembling single soliton pulse microcombs form from coherent pulse pairs. We propose to investigate a range of applications and new physical phenomena resulting from the pulse-pair mode locking modality. While the starting point for these studies will be the coupled-ring system and its unusual dispersion properties, the program will incorporate an additional electrically-controlled dispersion control mechanism that results from a frequency-Vernier coupling mechanism used in the coupled-ring systems. We will study this capability to induce electrical switching between bright and dark pulse generation in the same device and when pumped at a fixed wavelength. And, along with the pulse-pair generation, we propose to also investigate opportunities for control and application of other nonlinearities such as stimulated Brillouin scattering. Phenomena enabled by the presence of multiple dispersion bands within the coupled ring system will also be explored.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2024
- Source ID
- FA95502310587
Entities
People
- Kerry Vahala
Organizations
- Air Force Office of Scientific Research
- California Institute of Technology
- United States Air Force