Telecom‐Band Spontaneous Parametric Down‐Conversion in AlGaAs‐on‐Insulator Waveguides
Marlon Placke, Jan Schlegel, Felix Mann, Pietro Della Casa, Andreas Thies, M. Weyers, G. Tränkle, Sven Ramelow
Abstract
Abstract Widespread commercial adoption of telecom‐band quantum key distribution (QKD) will require fully integrated, room‐temperature transmitters. Implementing highly efficient spontaneous parametric down‐conversion (SPDC) on a platform that offers co‐integration of the pump laser has been an outstanding challenge. Here, using such a platform based on AlGaAs‐on‐insulator waveguides, telecom‐band SPDC (and SHG, second harmonic generation) is reported with exceedingly large efficiencies of 26 GHz generated pairs per mW over a 7 THz bandwidth, which would saturate the usable photon‐flux for a 70‐channel wavelength‐multiplexed QKD system at merely 1.7 mW of pump laser power.