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arXiv:1511.05617 · Optica

Two-photon interference from a bright single-photon source at telecom wavelengths

Je‐Hyung Kim, Tao Cai, Christopher J. K. Richardson, Richard P. Leavitt, Edo Waks A

Published May 31, 2016• 144 citations
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Abstract

Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beamsplitter, which implements effective photon-photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate two-photon interference at telecom wavelengths using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high out-coupling efficiency exceeding 36% after multi-photon correction. We also observe Purcell enhanced spontaneous emission rate up to 4. Using this source, we generate linearly polarized, high purity single photons at 1.3 micron wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement, which exhibits indistinguishable visibilities of 18% without post-selection and 67% with post-selection. Our results provide a promising approach to generate bright, deterministic single photons at telecom wavelength for applications in quantum networking and quantum communication.

DOI
10.1364/optica.3.000577

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Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beamsplitter, which implements effective photon-photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate two-photon interference at telecom wavelengths using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high out-coupling efficiency exceeding 36% after multi-photon correction. We also observe Purcell enhanced spontaneous emission rate up to 4. Using this source, we generate linearly polarized, high purity single photons at 1.3 micron wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement, which exhibits indistinguishable visibilities of 18% without post-selection and 67% with post-selection. Our results provide a promising approach to generate bright, deterministic single photons at telecom wavelength for applications in quantum networking and quantum communication.
Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beamsplitter, which implements effective photon-photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high out-coupling efficiency exceeding 46%, leading to detected photon count rates that would exceed 1.5 million counts per second. We also observe Purcell enhanced spontaneous emission rate as large as 4. Using this source, we generate linearly polarized, high purity single photons at telecom-wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement. Our results provide a promising approach to generate on-demand indistinguishable single photons at telecom wavelength for applications in quantum networking and quantum communication.
Highly efficient single photon sources are important building blocks for optical quantum information processing. For practical use and long-distance quantum communication, single photons should have fiber-compatible telecom wavelengths. In addition, most quantum communication applications require high degree of indistinguishability of single photons, such that they exhibit interference on a beam splitter. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem in particular at telecom wavelengths. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. To obtain the efficient single quantum dot emission, we employ the higher order mode in L3 photonic crystal cavity that shows a nearly Gaussian transverse mode profile and results in out-coupling efficiency exceeding 46 {\\%} and unusual bright single quantum dot emission exceeding 1.5 million counts per second at a detector. We also observe Purcell enhanced spontaneous emission rate as large as 4 and high linear polarization ratio of 0.96 for the coupled dots. Using this source, we generate high purity single photons at 1.3 ??m wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement.
On-demand single-photon sources operating at telecom wavelengths are crucial for quantum communication and photonic quantum technologies. In this work, we demonstrate high-purity, indistinguishable single-photon generation in the telecom O-band from an InAsP/InP nanowire quantum dot. We measured a single-photon purity of g2(0)=0.006±0.003 under above-band excitation. Furthermore, we characterize two-photon interference via Hong–Ou–Mandel measurements and achieve a photon indistinguishability of 81.1%±3.7% with a temporal postselection of a 300 ps time window and 5.6%±1.5% without temporal postselection. We estimate a first-lens source efficiency of ∼28%. These results highlight the potential of nanowire quantum dots as a promising source of telecom single photons for photonic quantum applications, offering deterministic positioning, efficient photon extraction, and scalable production.
Quantum dots are promising candidates for deterministic single-photon sources, yet achieving high photon indistinguishability at telecom wavelengths remains a critical challenge. Here, we report a quantum dot-based single-photon source operating in the telecommunications C-band that achieves a raw two-photon interference visibility of up to (91.7 ± 0.2)%, thus setting a new benchmark for indistinguishability in this spectral range. The device consists of an indium arsenide (InAs) quantum dot embedded within indium aluminum gallium arsenide (InAlGaAs) and integrated into a circular Bragg grating resonator. We explore multiple optical excitation schemes to optimize coherence and source performance. The demonstration of two-photon interference visibilities exceeding 90% from a quantum-dot emitter in the telecommunications C-band pushes solid-state single-photon sources further towards practical quantum communication and quantum networks.
Quantum dots are promising candidates for deterministic single-photon sources, yet achieving high photon indistinguishability at telecom wavelengths remains a critical challenge. Here, we report a quantum dot-based single-photon source operating in the telecommunications C-band that achieves a raw two-photon interference visibility of up to (91.7 ± 0.2)%, thus setting a new benchmark for indistinguishability in this spectral range. The device consists of an indium arsenide (InAs) quantum dot embedded within indium aluminum gallium arsenide (InAlGaAs) and integrated into a circular Bragg grating resonator. We explore multiple optical excitation schemes to optimize coherence and source performance. The demonstration of two-photon interference visibilities exceeding 90% from a quantum-dot emitter in the telecommunications C-band pushes solid-state single-photon sources further towards practical quantum communication and quantum networks.
High-performance single-photon sources at telecom C-band wavelentghs are key building blocks for applications in long-distance quantum communication. Here, we report the generation of highly indistinguishable, single photons at a clock-rate of 2.5 GHz. This is achieved by coherently driving the biexciton transition (T1XX=64(1) T_1^\mathrm{XX}=64(1)\,T1XX​=64(1)ps) of a semiconductor quantum dot embedded in a microcavity with strong asymmetric Purcell enhancement. Employing pulsed two-photon resonant excitation, strong multiphoton suppression with g(2)(0)<4%g^{(2)}(0) < 4\%g(2)(0)<4% and high two-photon-interference visibility of Vraw>85%V_\mathrm{raw}> 85\%Vraw​>85% is observed. The observed photon indistinguishability is close to the theoretical limit expected for the photonically engineered radiative cascade and matches values obtained at lower repetition rates. Our results show a substantial advancement towards interference-based quantum information protocols at unprecedented data rates in the telecom C-Band.