Low-threshold bistability of slow light in photonic-crystal waveguides

TL;DR

This paper demonstrates how photonic-crystal waveguides with Kerr nonlinear cavities can achieve ultra-low power optical bistability and switching by exploiting slow-light effects that enhance resonance quality and reduce power thresholds.

Contribution

It provides a design framework for low-threshold all-optical switching in photonic-crystal waveguides using slow-light-induced resonance enhancement.

Findings

Resonance quality factor scales inversely with group velocity.

Power threshold for switching scales as the square of group velocity.

Bistability can be achieved at ultra-low powers in the slow-light regime.

Abstract

We analyze the resonant transmission of light through a photonic-crystal waveguide side coupled to a Kerr nonlinear cavity, and demonstrate how to design the structure geometry for achieving bistability and all-optical switching at ultra-low powers in the slow-light regime. We show that the resonance quality factor in such structures scales inversely proportional to the group velocity of light at the resonant frequency and thus grows indefinitely in the slow-light regime. Accordingly, the power threshold required for all-optical switching in such structures scales as a square of the group velocity, rapidly vanishing in the slow-light regime.