On-chip optical spatial-domain integrator based on Fourier optics and metasurface

Chao Chen,Xinliang Zhang,Wei Qi,Yu Yu

doi:10.1515/nanoph-2021-0137

Abstract

Abstract Analog optical computing has been an innovation and research interest in last several years, thanks to the ultra-high speed (potential for real-time processing), ultra-low power consumption and capability of parallel processing. Although great efforts have been made recently, no on-chip optical spatial-domain integrator has been experimentally demonstrated, to the best of our knowledge. Based on Fourier optics and metasurface, we design and fabricate an on-chip optical integrator using silicon-on-insulator (SOI) platform. The proposed integrator is able to integrate the electric field in spatial domain. As a proof-of-concept demonstration, a representative optical signal is well integrated to the desired distribution. Compared with theoretical expectation, the similarity coefficients of the simulated and experimental results are 83 and 78%, respectively. The proposed scheme has potential of performing more complex and ultra-high-speed computing for artificial intelligence.

Highlights

Unprecedentedly large computing power is urgently needed, while developing advanced process for traditional electronic signal processing is becoming much more difficult and expensive
As a novel structure that can freely regulate light field as desired and has the advantages of being compact, the metasurface seems a perfect candidate for analog optical computing (AOC) [21, 22]
Most metasurface-based optical computing systems are established in free space, and assembling those free-space systems remains a tough task

Summary

Introduction

Unprecedentedly large computing power is urgently needed, while developing advanced process for traditional electronic signal processing is becoming much more difficult and expensive. Since the idea of performing spatial AOC with metamaterials was first proposed by Silva et al [4], a few spatial-domain devices have been illustrated, such as spatial filter [6], differentiator [7,8,9,10,11], integrator [9, 11,12,13], convolver [14], equation solver [15, 16] and correlator [17, 18]. As a novel structure that can freely regulate light field as desired and has the advantages of being compact, the metasurface seems a perfect candidate for AOC [21, 22]. A novel symmetry-slot on-chip metasurface is proposed to perform optical spatial-domain integration based on Fourier optics. The simulation under different incidences clarifies the universality of the proposed integrator

Operation principle and device design

Simulation and experimental verification

Conclusion