Robust, ultralow-loss, and broadband light-recycling for a nanophotonic delay line

Abstract

The optical delay line is a key building block for applications in photonics. It requires low loss, wide bandwidth, and small footprint. In this work, we adopt the light recycling approach based on spatial-mode multiplexing, and achieve high performance with a Mach-Zehnder interferometer (MZI)-based design, which significantly increases the fabrication error tolerance. The proposed nanophotonic delay lines allow fabrication errors of t10 nm over the broad bandwidth of 100 nm while maintaining the excess insertion loss below 0.5 dB. It will enable power-efficient, ultralow-loss, small-footprint, and broadband optical information processing capabilities in diverse applications. (C) 2022 Optica Publishing Group