Multi-mode microcavity frequency engineering through a shifted grating in a photonic crystal ring

Abstract

Frequency engineering of whispering-gallery resonances is essential in microcavity nonlinear optics. The key is to control the frequencies of the cavity modes involved in the underlying nonlinear optical process to satisfy its energy conservation criterion. Compared to the conventional method that tailors dispersion by the cross-sectional geometry, thereby impacting all cavity mode frequencies, grating-assisted microring cavities, often termed as photonic crystal microrings, provide more enabling capabilities through mode-selective frequency control. For example, a simple single period grating added to a microring has been used for single-frequency engineering in Kerr optical parametric oscillation (OPO) and frequency combs. Recently, this approach has been extended to multi-frequency engineering by using multi-period grating functions, but at the cost of increasingly complex grating profiles that require challenging fabrication. Here, we demonstrate a simple approach, which we term as shifted grating multiple mode splitting (SGMMS), where spatial displacement of a single period grating imprinted on the inner boundary of the microring creates a rotational asymmetry that frequency splits multiple adjacent cavity modes. This approach is easy to implement and presents no additional fabrication challenges than an un-shifted grating, and yet is very powerful in providing multi-frequency engineering functionality for nonlinear optics. We showcase an example where SGMMS enables OPO generation across a wide range of pump wavelengths in a normal-dispersion device that otherwise would not support OPO.

References in corpus (19)

• Efficient and low-noise single-photon-level frequency conversion interfaces using silicon nanophotonics
• Chip-integrated visible-telecom photon pair sources for quantum communication
• Spontaneous Pulse Formation in Edge-Less Photonic Crystal Resonators
• Nanophotonic spin-glass for realization of a coherent Ising machine
• Ultra-low-power second-order nonlinear optics on a chip
• High-Q slow light and its localization in a photonic crystal microring
• Tailoring microcombs with inverse-designed, meta-dispersion microresonators
• High-performance microresonator optical parametric oscillator on a silicon chip
• On-chip optical parametric oscillation into the visible: generating red, orange, yellow, and green from a near-infrared pump
• Selective engineering of cavity resonance for frequency matching in optical parametric processes
• A universal frequency engineering tool for microcavity nonlinear optics: multiple selective mode splitting of whispering-gallery resonances
• Fourier synthesis dispersion engineering of photonic crystal microrings for broadband frequency combs
• Highly-twisted states of light from a high quality factor photonic crystal ring
• Kerr optical parametric oscillation in a photonic crystal microring for accessing the infrared
• Fractional optical angular momentum and multi-defect-mediated mode re-normalization and orientation control in photonic crystal microring resonators
• Hybrid-mode-family Kerr optical parametric oscillation for robust coherent light generation on chip
• Integrated Optical Vortex Microcomb
• Integrated vortex soliton microcombs
• Wavelength-Accurate Nonlinear Conversion through Wavenumber Selectivity in Photonic Crystal Resonators