Integrated Source of Spectrally Filtered Correlated Photons for Large-Scale Quantum Photonic Systems

Nicholas C Harris,Dirk Englund,Michael Hochberg,Davide Grassani,Matteo Galli,Angelica Simbula,Christophe Galland,Daniele Bajoni,Tom Baehr-Jones,Mihir Pant

doi:10.1103/physrevx.4.041047

Abstract

We demonstrate the generation of quantum-correlated photon-pairs combined with the spectral filtering of the pump field by more than 95dB using Bragg reflectors and electrically tunable ring resonators. Moreover, we perform demultiplexing and routing of signal and idler photons after transferring them via a fiber to a second identical chip. Non-classical two-photon temporal correlations with a coincidence-to-accidental ratio of 50 are measured without further off-chip filtering. Our system, fabricated with high yield and reproducibility in a CMOS process, paves the way toward truly large-scale quantum photonic circuits by allowing sources and detectors of single photons to be integrated on the same chip.

Highlights

Integrated photonic circuits have emerged as a promising platform for quantum information processing [1,2,3]
We demonstrate the generation of quantum-correlated photon pairs combined with the spectral filtering of the pump field by more than 95 dB on a single silicon chip using electrically tunable ring resonators and passive Bragg reflectors
Our system, fabricated with high yield and reproducibility in a CMOS-compatible process, paves the way toward large-scale quantum photonic circuits by allowing sources and detectors of single photons to be integrated on the same chip

Summary

INTRODUCTION

Integrated photonic circuits have emerged as a promising platform for quantum information processing [1,2,3]. We transfer the photon pairs from chip A via a silica-fiber connection to a similar system on a second chip [chip B, Fig. 1(f)] in which we filter any residual pump with the DBR and use the add-drop rings to demultiplex the signal and idler photons [Fig. 1(d)]. These photon pairs are routed to different waveguides before detection with off-chip superconducting-nanowire single-photon detectors (SNSPDs) and time-correlation. Our results highlight the promises of CMOS photonics for emerging quantum technologies such as quantum key distribution [53,54,55,56,57,58,59,60,61,62,63], quantum simulations and random walks [4,46,64,65,66,67,68], and possibly quantum computation [69,70,71,72,73,74]

SYSTEM DESIGN

Idler add-drop ring 10 PIN photodiode

SINGLE-CHIP PUMP REJECTION

DISCUSSION AND OUTLOOK

CONCLUSION