Laser written waveguide photonic quantum circuits

TL;DR

This paper introduces a rapid, maskless laser writing technique for creating three-dimensional photonic quantum circuits, demonstrating high-quality components and quantum interference effects in integrated optics.

Contribution

The authors present a novel ultrafast laser processing method for fabricating 3D photonic quantum circuits without lithography, enabling faster development and scaling of quantum optical devices.

Findings

Directional couplers perform as well as lithographic devices

High-performance interferometers demonstrated

Multi-photon quantum interference observed in integrated optics

Abstract

We report photonic quantum circuits created using an ultrafast laser processing technique that is rapid, requires no lithographic mask and can be used to create three-dimensional networks of waveguide devices. We have characterized directional couplers--the key functional elements of photonic quantum circuits--and found that they perform as well as lithographically produced waveguide devices. We further demonstrate high-performance interferometers and an important multi-photon quantum interference phenomenon for the first time in integrated optics. This direct-write approach will enable the rapid development of sophisticated quantum optical circuits and their scaling into three-dimensions.