Laser written waveguides to the sample edge

TL;DR

This paper introduces a laser writing technique that enables fabrication of waveguides directly at the sample edge in glass, eliminating the need for polishing and improving fiber-to-circuit transmission.

Contribution

It presents a novel method using amplitude masking and increased pulse energy to write waveguides unaffected by edge aberrations in glass substrates.

Findings

Waveguides can be written at the sample edge with high mode profile quality.

Transmission from fiber to photonic circuit is significantly improved.

Method works for different depths in fused silica and borosilicate glass.

Abstract

A method is presented for fabrication of femtosecond laser written waveguides in glass to remove the need for polishing of substrates after processing. It is shown that by amplitude masking the fabrication laser beam near the sample edge and increasing the pulse energy it is possible to write waveguides that are not affected by edge aberrations and display mode profiles well matched to single mode fiber. Results are presented for different depths in fused silica and borosilicate glass substrates. The transmission from fiber to photonic circuit is significantly improved for situations where it is not possible to polish glass substrates after laser writing, creating new opportunities in photonic packaging.