3-D Integrated Flexible Glass Photonics

TL;DR

This paper introduces a monolithic fabrication method for flexible glass photonics that achieves high optical performance and mechanical flexibility, enabling advanced 3-D integrated photonic devices on plastic substrates.

Contribution

The work presents a novel monolithic fabrication process and a new mechanics theory for flexible glass photonics, significantly improving processing throughput, yield, and device performance.

Findings

Achieved record optical quality factor (Q=460,000)

Demonstrated flexible devices with sub-millimeter bending radius

Provided a new mechanics model for large elastic mismatch laminates

Abstract

Photonic integration on plastic substrates enables emerging applications ranging from flexible interconnects to conformal sensors on biological tissues. Such devices are traditionally fabricated using pattern transfer, which is complicated and has limited integration capacity. Here we pioneered a monolithic approach to realize flexible, high-index-contrast glass photonics with significantly improved processing throughput and yield. Noting that the conventional multilayer bending theory fails when laminates have large elastic mismatch, we derived a mechanics theory accounting for multiple neutral axes in one laminated structure to accurately predict its strain-optical coupling behavior. Through combining monolithic fabrication and local neutral axis designs, we fabricated devices that boast record optical performance (Q=460,000) and excellent mechanical flexibility enabling repeated bending down to sub-millimeter radius without measurable performance degradation, both of which represent major improvements over state-of-the-art. Further, we demonstrate that our technology offers a facile fabrication route for 3-D high-index-contrast photonics difficult to process using traditional methods.