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2024
Conference Paper
Title
Advances in entangled-photon sources and single-photon avalanche diodes for quantum technologies in the SWIR
Abstract
Quantum sensing and quantum communication systems rely on high-performance single- or entangled-photon sources and single-photon detectors enabling experiments based on the quantum nature of single photons. In this contribution, we discuss the development of an entangled-photon source delivering entangled photon pairs with wavelengths of about 1550 nm alongside with single-photon avalanche detectors (SPADs) for the short-wave infrared (SWIR) and for the extended SWIR (eSWIR) spectral range.
The fabrication processes of such quantum-enabling technologies is highlighted. The entangled-photon source is based on AlGasAs Bragg-reflection waveguides. Very low difference in effective refractive index of TE and TM polarized photons - important for high polarization entanglement without external compensation - as well as high single and coincidence count rates were achieved. For the fabrication of InGaAs/InP SWIR SPADs, the key technology is the planar process technology via zinc diffusion to produce spatially confined p-type regions. For the zinc-diffusion process, a novel method of selective epitaxial overgrowth was developed, achieving the intended double-well diffusion profile. Experimental data of thus fabricated InGaAs/InP SPADs show the expected dark.current, photo-current, and multiplication-gain characteristics in linear-mode operation as well as breakthrough behaviour in Geiger-mode operation at 240 K, which is a typical operating temperature for InGaAs/InP SPADs achievable by thermoelectric cooling. GaSb-based SPADs for the eSWIR are fabricated in a mesa approach showing the expected dark current behaviour as well. All three different devices are linked by enabling quantum technologies in the (e) SWIR as well as by using our III/V-semiconductor technology facilities.
The fabrication processes of such quantum-enabling technologies is highlighted. The entangled-photon source is based on AlGasAs Bragg-reflection waveguides. Very low difference in effective refractive index of TE and TM polarized photons - important for high polarization entanglement without external compensation - as well as high single and coincidence count rates were achieved. For the fabrication of InGaAs/InP SWIR SPADs, the key technology is the planar process technology via zinc diffusion to produce spatially confined p-type regions. For the zinc-diffusion process, a novel method of selective epitaxial overgrowth was developed, achieving the intended double-well diffusion profile. Experimental data of thus fabricated InGaAs/InP SPADs show the expected dark.current, photo-current, and multiplication-gain characteristics in linear-mode operation as well as breakthrough behaviour in Geiger-mode operation at 240 K, which is a typical operating temperature for InGaAs/InP SPADs achievable by thermoelectric cooling. GaSb-based SPADs for the eSWIR are fabricated in a mesa approach showing the expected dark current behaviour as well. All three different devices are linked by enabling quantum technologies in the (e) SWIR as well as by using our III/V-semiconductor technology facilities.
Author(s)
