On-chip optical filters with designable characteristics based on an interferometer with embedded silicon photonic structures

TL;DR

This paper presents a novel on-chip optical filter design using negative index photonic crystal Mach-Zehnder interferometers, enabling tunable, high-performance filtering with deterministic control over bandwidth and rejection ratios.

Contribution

The work introduces a new approach for engineering flat-top optical filters with tunable multi-level responses using embedded silicon photonic structures and photonic crystal band diagrams.

Findings

Experimental demonstration of flat-top filters at near-infrared wavelengths.

Ability to design high-pass, low-pass, band-pass, and band-reject filters.

Filters with tunable multi-level spectral responses and polarization control.

Abstract

We demonstrate chip-scale flat-top filters at near-infrared wavelengths using negative index photonic crystal based Mach Zehnder interferometers. Supported by full three-dimensional numerical simulations, we experimentally demonstrate a new approach for engineering high-pass, low-pass, band-pass, and band-reject filters, based on designing the photonic band diagram both within the band-gap frequency region and away from it. We further show that our approach can be used to design filters that have tunable multi-level response for different sections of the spectrum and for different polarizations. This configuration enables deterministic control of the bandwidth and the rejection ratio of filters for integrated photonic circuits.