Waveguide-Integrated Photon Detectors for Enabling Quantum Technologies

Kovalyuk V., Venediktov I., Korovin V. +12 more

Dondu Sahin, Alessandro Gaggero, Roberto Leoni +1 more

Fiore, Gaggero, Sprengers +8 more

Guanglong He, Rui Ge, Hang Han +12 more

Integration of photon number resolving superconducting nanowire single-photon detectors (PNR-SNSPDs) with nanophotonic waveguides is a key technology that enables a broad range of quantum technologies on chip-scale platforms. However, all on-chip integrated SNSPDs are fabricated above the waveguide layer, which makes the characteristics of the detector’s photoresponsive film material only depend on the waveguide material, thus lowering the waveguide selectivity. Here, we report an on-chip integrated SNSPD based on optimized topology that the nanowire is sandwiched between the waveguide and the substrate. This device maintains the film characteristics with different waveguides and the light transmitted from the upper waveguide to the substrate is absorbed by the film, which not only increases the selectivity of the waveguide, but also improves light absorption of SNSPD. As an example, SiO2 waveguide with the lower optical transmission loss was fabricated in an integrated PNR-SNSPD. We proposed a multi-channel photon response amplitude superposition multiplexing scheme, which realized photon detection by integrating SNSPD on the optical transmission waveguide in the photonic integrated circuit. The solution not only can effectively read the photon responses of multiple SNSPDs through a readout port, but also can distinguish the number of photons and the corresponding response channels through the amplitude of the readout circuit, thereby realizing a photonic integrated circuit with multiple modes. Finally, we prepared a 4-channel integrated PNR-SNSPD, which resolved the number of photons and corresponding photon response positions through 16 different signal amplitudes. This result is compatible of a wide range of waveguide materials, overcoming the limitation of single photon detector integrated on waveguide for quantum photonic integrated circuit.

Jonathan C. F. Matthews, Alberto Politi, André Stefanov +14 more

Michael G. Tanner, L. San Emeterio Alvarez, Weitao Jiang +3 more

Superconducting nanowire single photon detectors (SNSPDs) are a key enabling technology for optical quantum information science. In this paper we demonstrate a SNSPD fabricated on lithium niobate, an important material for high speed integrated photonic circuits. We report a system detection efficiency of 0.15% at a 1 kHz dark count rate with a maximum of ~1% close to the critical current at 1550 nm wavelength for a parallel wire SNSPD with front side illumination. There is clear scope for improving on this performance with further materials optimization. Detector integration with a lithium niobate optical waveguide is simulated, demonstrating the potential for high single photon detection efficiency in an integrated quantum optic circuit.