Nonlinearity Induced Critical Coupling

TL;DR

This paper investigates how Kerr nonlinearity affects critical coupling in optical systems, showing that nonlinearity can inhibit or induce near-complete scattering suppression depending on system detuning.

Contribution

It demonstrates that nonlinearity can both inhibit null-scattering at critical coupling and enable near-complete suppression when detuned, revealing new control mechanisms.

Findings

Nonlinearity inhibits null-scattering at critical coupling.

Detuned systems can achieve near-complete scattering suppression due to nonlinearity.

Critical coupling involves a delicate balance of amplitude and phase relations.

Abstract

We study a critically coupled system (Opt. Lett., \textbf{32}, 1483 (2007)) with a Kerr-nonlinear spacer layer. Nonlinearity is shown to inhibit null-scattering in a critically coupled system at low powers. However, a system detuned from critical coupling can exhibit near-complete suppression of scattering by means of nonlinearity-induced changes in refractive index. Our studies reveal clearly an important aspect of critical coupling as a delicate balance in both the amplitude and the phase relations, while a nonlinear resonance in dispersive bistability concerns only the phase.