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

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.