On-chip broadband non-reciprocal light storage

TL;DR

This paper introduces a chip-based non-reciprocal delay method that transfers optical pulses to acoustic waves, enabling broadband, linear, and wavelength-preserving signal processing without complex structures.

Contribution

It presents a novel on-chip non-reciprocal delay scheme using uni-directional opto-acoustic transfer, surpassing previous bandwidth and complexity limitations.

Findings

Achieved broadband non-reciprocal delay exceeding intrinsic linewidth

Demonstrated linear operation over wide power range

Maintained wavelength preservation without multi-mode structures

Abstract

Breaking the symmetry between forward and backward propagating optical modes is of fundamental scientific interest and enables crucial functionalities, such as isolators, circulators, and duplex communication systems. Whereas there has been progress in achieving optical isolation on-chip, integrated broadband non-reciprocal signal processing functionalities that enable transmitting and receiving via the same low-loss planar waveguide, without altering the frequency or mode of the signal, remain elusive. Here, we demonstrate a non-reciprocal delay scheme based on the uni-directional transfer of optical data pulses to acoustic waves in a chip-based integration platform. We experimentally demonstrate that this scheme is not impacted by simultaneously counter-propagating optical signals. Furthermore, we achieve a bandwidth more than an order of magnitude broader than the intrinsic opto-acoustic linewidth, linear operation for a wide range of signal powers, and importantly, show that this scheme is wavelength preserving and avoids complicated multi-mode structures..