Quantum integrated photonics and superconducting detectors

Quantum computers offer the tantalizing opportunity to solve computationally hard problems that would take an infinite time to be processed with future supercomputers. In order to be functional, quantum computers have to count on a scalable hardware platform and be able to run any quantum algorithm in a reliable way.

In order to address these requirements, photons interacting in photonic circuits have been considered a promising candidate as qubits. Light is inherently low-noise, offers high transmission bandwidth and can benefit from a mature low-cost technology.

IFN CNR works on the development of fundamental building blocks required for the implementation of such quantum computers by realizing both photonics circuits (Fig.1) and superconducting nanowire single photon detectors (SNSPDs). [1-2-3]


Fig. 1 Integrated optical circuits


Fig. 2 a) SNSPD integrated atop a ridge waveguide b) Contour and vector plot of the electric field (amplitude and direction) or the fundamental mode


In addition to detect light with high efficiency, low jitter and dark counts in a wavelength range spanning from UV to mid-Infrared, SNSPDs can be conveniently integrated over waveguides by evanescent coupling (Fig.2).  [4]

Advanced functionalities, as the ability to resolve photon number distribution of the incoming photon string (Fig 3 ) [5-6] or the efficient readout of several elements integrated atop a photonic circuit, can be further exploited (Fig 4). [7]


Fig. 4 a) Scanning electron micrograph of the SNSPD array b) Count rate versus trigger level (TL) for different Ib of the detector c) Output signal recording (Ib = 17.0 μA) taken from the oscilloscope


[1] Single photon detection with superconducting nanowires on crystalline silicon carbide F Martini, A Gaggero, F Mattioli, R Leoni Optics express 27 (21), 29669-29675

[2] Superconducting nanowire photon-number-resolving detector at telecommunication wavelengths A Divochiy, F Marsili, D Bitauld, A Gaggero, R Leoni, F Mattioli, A Korneev, et al.Nature Photonics 2 (5), 302-306

[3] Nanowire superconducting single-photon detectors on GaAs for integrated quantum photonic applications A Gaggero, SJ Nejad, F Marsili, F Mattioli, R Leoni, D Bitauld, D Sahin, … Applied Physics Letters 97 (15), 151108

[4] Waveguide superconducting single-photon detectors for integrated quantum photonic circuits JP Sprengers, A Gaggero, D Sahin, S Jahanmirinejad, G Frucci, F Mattioli, … Applied Physics Letters 99 (18), 181110

[5] Photon-counting and analog operation of a 24-pixel photon number resolving detector based on superconducting nanowires F Mattioli, Z Zhou, A Gaggero, R Gaudio, R Leoni, A Fiore Optics express 24 (8), 9067-9076


People involved:

Fabio Chiarello

Sara Cibella

Alessandro Gaggero

Roberto Leoni

Francesco Mattioli

Francesco Martini

Giorgio Pettinari

Guido Torrioli


Research units: