Quantum-correlated photon pairs generated in a commercial 45  nm complementary metal-oxide semiconductor microelectronic chip

Abstract

Correlated photon pairs are a fundamental building block of quantum photonic systems. While pair sources have previously been integrated on silicon chips built using customized photonics manufacturing processes, these often take advantage of only a small fraction of the established techniques for microelectronics fabrication and have yet to be integrated in a process which also supports electronics. Here we report the first demonstration of quantumcorrelated photon pair generation in a device fabricated in an unmodified advanced (sub-100 nm) complementary metal-oxide-semiconductor (CMOS) process, alongside millions of working transistors. The microring resonator photon pair source is formed in the transistor layer structure, with the resonator core formed by the silicon layer typically used for the transistor body. With ultra-low continuous-wave on-chip pump powers ranging from 5 µW to 400 µW, we demonstrate pair generation rates between 165 Hz and 332 kHz using >80% efficient WSi superconducting nanowire single photon detectors. Coincidences-to-accidentals ratios consistently exceeding 40 were measured with a maximum of 55. In the process of characterizing this source we also accurately predict pair generation rates from the results of classical stimulated four-wave mixing measurements. This proof-of-principle device demonstrates the potential of commercial CMOS microelectronics as an advanced quantum photonics platform with capability of large volume, pristine process control, and where state-of-the-art high-speed digital circuits could interact with quantum photonic circuits.This manuscript describes work of the U.S. government and is not subject to copyright.

Silicon photonic entangled photon-pair and heralded single photon generation with CAR > 12,000 and g^(2)(0) < 0006

“…There is recent interest in silicon photonic approaches to generating, manipulating and detecting quantum light, including entangled photon pairs and heralded single photons as resources for quantum optical communications and information processing. Integrated photonic structures, such as waveguides and micro-resonators, can be used for photon pair and heralded single photon generation using the nonlinear optical process of spontaneous four-wave mixing (SFWM) [1][2][3][4][5][6][7][8][9] . The intrinsic rate of nonlinear optical processes increases as the mode volume decreases, which reduces the pump power requirements of silicon microrings used for pair generation to sub-milliwatt levels 8 , and the device footprint to about one hundred square-microns 2,3 .…”

Large-scale quantum photonic circuits in silicon

“…Demonstrations of structures that enhance photon generation rates via SFWM include rectangular waveguides [50,[77][78][79], and microring resonators [38,41,43,[80][81][82][83][84][85][86][87][88]; see Figure 5D-F. As SFWM involves the annihilation of two photons, pair generation rates scale with the square of the optical intensity. With standard single-mode waveguide geometries of 500 nm by 220 nm, optical intensities in integrated structures are enhanced by the inverse of the effective mode area [70] with respect to bulk-silicon SFWM pair sources.…”

Photon-pair generation in a lossy microring resonator. I. Theory

“…where the value of g spdc (ω) and g sf wm (ω) [12,13] depend on the volume V ring of the ring mode, and the nonlinear susceptibilities χ (2) and χ (3) are accessed uniformly in the ring. Heren is the average index of refraction of the ring (assumed constant) and 0 is the permittivity of free space.…”

“…Over the last decade, advances in chip-based fabrication have made micron-scale, high quality factor Q integrated optical microring resonators (mrr) coupled to an external bus ideal sources of entangled photon pair generation, requiring only µWs of pump power [1][2][3][4][5][6]. Such high-Q mircoring resonators exhibit nonlinear optical properties allowing for biphoton generation arising from the χ (2) processes of spontaneous parametric down conversion (SPDC), and the χ (3) processes of spontaneous four-wave mixing (SFWM).…”