Digital Waveguide Adiabatic Passage Part 2: Experiment

TL;DR

This paper reports on the fabrication and characterization of three-waveguide digital adiabatic passage devices using femtosecond laser writing, demonstrating high-fidelity operation with strong asymmetric behavior and broad bandwidth.

Contribution

It introduces a novel digital adiabatic passage device with a digitized central waveguide, showing high fidelity and low loss, advancing integrated photonic control.

Findings

High fidelity (>90%) operation in counter-intuitive scheme

Strong suppression of transmission in intuitive scheme

Broad bandwidth (~60nm) centered at 823nm

Abstract

Using a femtosecond laser writing technique, we fabricate and characterise three-waveguide digital adiabatic passage devices, with the central waveguide digitised into five discrete waveguidelets. Strongly asymmetric behaviour was observed, devices operated with high fidelity in the counter-intuitive scheme while strongly suppressing transmission in the intuitive. The low differential loss of the digital adiabatic passage designs potentially offers additional functionality for adiabatic passage based devices. These devices operate with a high contrast ($>\!90\%$) over a 60nm bandwidth, centered at $\sim 823$nm.