Fano resonance from a one-dimensional topological photonic crystal

TL;DR

This paper demonstrates the design and experimental realization of an ultra-compact one-dimensional topological photonic crystal that produces a pronounced Fano resonance through interference between topological boundary states and leaky modes.

Contribution

It introduces a novel 1D topological photonic crystal integrated in a silicon waveguide that achieves strong Fano resonance effects experimentally.

Findings

Achieved Fano resonance with 33 dB extinction ratio

Demonstrated broadband flat background with high slope ratio

Validated interference mechanism between boundary and leaky modes

Abstract

An ultra-compact one-dimensional topological photonic crystal (1D-TPC) is designed in a single mode silicon bus-waveguide to generate Fano resonance lineshape. The Fano resonance comes from the interference between the discrete topological boundary state of the 1D-TPC and the continuum high-order leaky mode of the bus-waveguide. Standalone asymmetric Fano resonance lineshapes are obtained experimentally in the waveguide transmission spectrum with a maximum extinction ratio of 33 dB and a slope ratio of 10 dB/nm over a broadband flat background.