Distributed delay-line interferometer based on a Bragg grating in transmission mode

TL;DR

This paper introduces a novel delay line interferometer design using a single transmission-mode Bragg grating, simplifying implementation and broadening applicability across various optical technologies.

Contribution

It presents the first demonstration of a delay line interferometer based solely on forward Bragg scattering in transmission mode, replacing traditional dual-path setups.

Findings

Successfully designed and fabricated a fiber Bragg grating demonstrating the concept

Experimental results confirm the transmission-mode DLI functionality

Applicable to various Bragg grating technologies

Abstract

A novel approach for a delay line interferometer (DLI) based purely on forward Bragg scattering is proposed. We have numerically and experimentally demonstrated that a Bragg grating can deliver the functionality of a DLI in its transmission mode along a single common interfering optical path, instead of the conventional DLI implementation with two interfering optical paths. As a proof of concept, a fiber Bragg grating has been designed and fabricated, showing the desired functionality in the transmission mode of the Bragg grating. The proposed "Bragg-DLI" approach is applicable to any kind of Bragg grating technology, such as volume Bragg gratings, dielectric mirrors, silicon photonics, and other optical waveguide based Bragg structures.