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arXiv:1806.01245 · Optics Letters

Terahertz-bandwidth switching of heralded single photons

Connor Kupchak, Jennifer Erskine, Duncan G. England, Benjamin Sussman

Published Mar 8, 2019• 40 citations
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Abstract

Optically induced ultrafast switching of single photons is demonstrated by rotating the photon polarization via the Kerr effect in a commercially available single-mode fiber. A switching efficiency of 97% is achieved with a ∼1.7 ps switching time and signal-to-noise ratio of ∼800. Preservation of the single-photon properties is confirmed by measuring no significant increase in the second-order autocorrelation function g(2)(0). These values are attained with only nanojoule-level pump energies that are produced by a laser oscillator with 80 MHz repetition rate. The results highlight a simple device capable of both high-bandwidth operations and preservation of single-photon properties for applications in photonic quantum processing and ultrafast time-gating or switching.

DOI
10.1364/ol.44.001427

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Optically induced ultrafast switching of single photons is demonstrated by rotating the photon polarization via the Kerr effect in a commercially available single-mode fiber. A switching efficiency of 97% is achieved with a ∼1.7 ps switching time and signal-to-noise ratio of ∼800. Preservation of the single-photon properties is confirmed by measuring no significant increase in the second-order autocorrelation function g(2)(0). These values are attained with only nanojoule-level pump energies that are produced by a laser oscillator with 80 MHz repetition rate. The results highlight a simple device capable of both high-bandwidth operations and preservation of single-photon properties for applications in photonic quantum processing and ultrafast time-gating or switching.
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The realization of an ultra-fast source of heralded single photons emitted at the wavelength of 1540 nm is reported. The presented strategy is based on state-of-the-art telecom technology, combined with off-the-shelf fiber components and waveguide non-linear stages pumped by a 10 GHz repetition rate laser. The single photons are heralded at a rate as high as 2.1 MHz with a heralding efficiency of 42%. Single photon character of the source is inferred by measuring the second-order autocorrelation function. For the highest heralding rate, a value as low as 0.023 is found. This not only proves negligible multi-photon contributions but also represents the best measured value reported to date for heralding rates in the MHz regime. These prime performances, associated with a device-like configuration, are key ingredients for both fast and secure quantum communication protocols.
The realization of an ultra-fast source of heralded single photons emitted at the wavelength of 1540 nm is reported. The presented strategy is based on state-of-the-art telecom technology, combined with off-the-shelf fiber components and waveguide non-linear stages pumped by a 10 GHz repetition rate laser. The single photons are heralded at a rate as high as 2.1 MHz with a heralding efficiency of 42%. Single-photon character of the source is inferred by measuring the second-order autocorrelation function. For the highest heralding rate, a value as low as 0.023 is found. This not only proves negligible multi-photon contributions but also represents one of the best measured values reported to date for heralding rates in the MHz regime. These performances, associated with a device-like configuration, are key ingredients for both fast and secure quantum communication protocols.
Manipulating the frequency and bandwidth of light is crucial in classical and quantum applications including communication, spectroscopy, imaging, and signal processing. Such capabilities also offer potential for interfacing disparate quantum systems in quantum networking and for quantum information processing. We experimentally demonstrate deterministic, broadband frequency control of heralded telecom-band single photons via cross-phase modulation in a short length of single-mode fiber. An intense, ultrafast pump pulse imposes a transient, intensity-dependent refractive-index gradient which imparts a tunable phase shift on the single photons. We present absolute frequency shifts of up to +6.42±0.06 THz and -5.82±0.02 THz, and bandwidth manipulation ranging from a factor of 0.76±0.03 to 7.1±0.4 times that of the input. Spectral measurements are acquired with a time-of-flight spectrometer and superconducting nanowire detectors. Our scheme offers a compact and scalable route to spectral routing and bandwidth engineering for ultrafast quantum networking and quantum information processing.