A continuum of bright and dark-pulse states in a photonic-crystal resonator

Abstract

Nonlinearity is a powerful determinant of physical systems. Controlling nonlinearity leads to interesting states of matter and new applications. In optics, diverse families of continuous and discrete states arise from balance of nonlinearity and group-velocity dispersion (GVD). Moreover, the dichotomy of states with locally enhanced or diminished field intensity depends critically on the relative sign of nonlinearity and either anomalous or normal GVD. Here, we introduce a resonator with unconditionally normal GVD and a single defect mode that supports both dark, reduced-intensity states and bright, enhanced-intensity states. We access and explore this dark-to-bright pulse continuum by phase-matching with a photonic-crystal resonator, which mediates the competition of nonlinearity and normal GVD. These stationary temporal states are coherent frequency combs, featuring highly designable spectra and ultralow noise repetition-frequency and intensity characteristics. The dark-to-bright continuum illuminates physical roles of Kerr nonlinearity, GVD, and laser propagation in a gapped nanophotonic medium.

Counterpropagating light in ring resonators: Switching fronts, plateaus, and oscillations

“…A modification to this setup to incorporate bidirectional pumping should allow for the generation of counterpropagating SF states. Single input laser setups in the presence of back scattering have indeed predicted and observed Maxwell point front solutions in micro-ring resonators [14,15]. Back scattering of the pump laser results in a counterpropagating field, allowing for a single laser setup to produce plateaus that can be the result of extending our model to these configurations.…”

“…Bright solitons formed by two SFs are instead stable in counterpropagation due to the robustness introduced by global coupling but the SFs will still annihilate if brought too close to each other. Such states have been observed in single laser setups [14]. In the limit of zero dispersion, bright structures can be made arbitrarily narrow when changing the detuning.…”

“…In particular we demonstrate that stationary solutions with two kinks in one of the counterpropagating fields are strongly related to similar solutions in a single normally dispersive LLE at the Maxwell point. Such stationary states have been observed with single input laser setups where a counterpropagating field is induced by backscattering [14,15], where a connection with the Maxwell point (see Section III) is also made.…”

“…The configuration and parameters used here differ from those used in [14,15] in that we consider energy injection on both fields. It is important to note that for E F = E B and θ F = θ B the system is perfectly symmetric upon the exchange of the forward and backward fields.…”

Photonic Multiplexing Techniques for Optical Neuromorphic Computing

“…Microcombs generated via parametric oscillation in high-Q micro-resonators, are promising optical frequency comb sources, as they offer a large number of wavelengths in integrated platforms. Significant advances have been made in microcombs, leading to a wideband, compact, high-energy-efficiency (even battery driven operation), turnkey and mass-producible comb sources for WDM-based ONNs [173][174][175][176][177][178][179][180][181][182][183].…”