High-Efficiency Shallow-Etched Grating on GaAs Membranes for Quantum Photonic Applications

TL;DR

This paper presents a shallow-etched GaAs grating that significantly improves fiber coupling efficiency and photon collection in quantum photonic circuits, enabling better integration of quantum dots with optical fibers.

Contribution

The authors designed and fabricated a shallow-etched grating on GaAs membranes that achieves high coupling efficiency and low back reflection, advancing quantum photonic integration.

Findings

Fiber-coupling efficiency >60% at 930 nm

Back reflection <1%

Sixfold increase in photon collection from quantum dots

Abstract

We have designed and fabricated a shallow-etched grating on gallium arsenide nanomembranes for efficient chip-to-fiber coupling in quantum photonic integrated circuits. Experimental results show that the grating provides a fiber-coupling efficiency of >60 %, a greatly suppressed back reflection of <1 % for the designed wavelength of 930 nm, and a 3-dB bandwidth of >43 nm. Highly efficient single-photon collection from embedded indium arsenide quantum dots to an optical fiber was realized with the designed grating, showing an average sixfold increase in photon count compared to commonly used circular gratings, offering an efficient interface for on-chip quantum information processing.