Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Quantum key distribution using a semiconductor quantum dot source emitting at a telecommunication wavelength

P. M. Intallura, M. B. Ward, O. Z. Karimov, Zhiliang L. Yuan, Patrick See, Andrew J. Shields, P. Atkinson, D. A. Ritchie

Published Jan 23, 2008• 0 citations
Publisher

Abstract

We present the first demonstration of telecom fiber-based quantum key distribution using single photons from a quantum dot in a pillar microcavity. The source offers both telecommunication wavelength operation at 1.3 microns and Purcell enhancement of the spontaneous emission rate. Several emission lines from the InAs/GaAs quantum dot are identified, including the exciton-biexciton cascade and charged excitonic emission. We show an order of magnitude increase in the collected intensity of the emission from a charged excitonic state when temperature tuned onto resonance with the HE11 mode of the pillar microcavity, as compared to the off-resonance intensity. Above- and below-GaAs-bandgap optical excitation was used and the effect of the excitation energy on the photoluminescence investigated. Exciting below the GaAs-bandgap offers significant improvement in the quality of the single photon emission and a reduction of the multi-photon probability to 0.1 times the value for Poissonian light was measured, before subtraction of detector dark counts, the lowest value recorded to date for a quantum dot source at a fibre wavelength. We observe also the first evidence of Purcell enhancement of the spontaneous emission rate for a single telecommunication wavelength quantum dot in a pillar microcavity. We have incorporated the source into a phase encoded interferometric scheme implementing the BB84 quantum cryptography protocol and distributed a key, secure from the pulse splitting attack, over standard telecommunication optical fibre. We show a transmission distance advantage over that possible with (length-optimized) uniform intensity weak coherent pulses at 1310 nm in the same system.

DOI
10.1117/12.763412

Related papers

Quantum key distribution using a triggered quantum dot source emitting near 1.3μm

Philip Intallura, M. B. Ward, O. Z. Karimov +5 more

We report the distribution of a cryptographic key, secure from photon number splitting attacks, over 35km of optical fiber using single photons from an InAs quantum dot emitting ∼1.3μm in a pillar microcavity. Using below GaAs-bandgap optical excitation, we demonstrate suppression of multiphoton emission to 10% of the Poissonian level without detector dark count subtraction. The source is incorporated into a phase encoded interferometric scheme implementing the BB84 protocol for key distribution over standard telecommunication optical fiber. We show a transmission distance advantage over that possible with (length-optimized) uniform intensity weak coherent pulses at 1310nm in the same system.

arXiv:0710.0565•Applied Physics Letters•Oct 15, 2007•80 citations

Quantum communication using single photons from a semiconductor quantum dot emitting at a telecommunication wavelength

P. M. Intallura, M. B. Ward, O. Z. Karimov +5 more

Quantum key distribution with single photons from a telecommunication-wavelength quantum dot source is performed over a standard optical fibre link. The source was operated at a temperature of 70 K and gave g(2)(0)~0.166 with an efficiency of 5% after coupling into the single-mode fibre. Correlation results are quoted without subtraction of detector dark counts and g(2)(0) as low as 0.1 was measured, at reduced efficiency. This source enabled a proof-of-principle demonstration of quantum key distribution over 35 km of fibre using the BB84 protocol and phase encoding.

Journal of Optics A Pure and Applied Optics•Mar 18, 2009•27 citations

Quantum key distribution system in standard telecommunications fiber using a short wavelength single photon source

Robert John Collins, Patrick J. Clarke, Verónica Fernández +8 more

A demonstration of the principles of quantum key distribution (QKD) is performed using a single-photon source in a proof of concept test-bed over a distance of 2 km in standard telecommunications optical fiber. The single-photon source was an optically-pumped quantum dot in a microcavity emitting at a wavelength of 895 nm. Characterization of the QKD parameters was performed at a range of different optical excitation powers. An investigation of the effect of varying the optical excitation power of the quantum dot microcavity on the quantum bit error rate and cryptographic key exchange rate of the system are presented.

arXiv:1004.4754•Journal of Applied Physics•Apr 1, 2010•32 citations

Quantum Key Distribution with a Negatively Charged Quantum Dot Single-Photon Source

Parvendra Kumar

Various quantum key distribution (QKD) protocols require bright single-photon sources with a very low probability of multiphoton emission. In this work, we investigate single-photon generation from a negatively charged quantum dot embedded in an elliptical pillar microcavity, driven by either resonant excitation or adiabatic rapid passage (ARP). Our results show that ARP excitation significantly suppresses multiphoton emission and improves photon indistinguishability compared to resonant excitation. We further evaluate the secure key rates of both BB84 and twin-field QKD (TF-QKD) using a quantum-dot single-photon source and compare its performance with that of Poisson-distributed sources (PDS), such as weak coherent pulses. The analysis reveals that ARP provides a modest but consistent enhancement in secure key rate relative to resonant excitation. We show that quantum-dot single-photon sources offer improved performance compared to PDS sources at short and intermediate distances within the chosen parameter regime; however, at longer distances, PDS sources slightly surpass them in both decoy-state BB84 and TF-QKD under the same conditions.

quant-pharXiv:2601.18518•Jan 27, 2026•0 citations

Quantum key distribution with a negatively charged quantum dot single-photon source

Parvendra Kumar

Various quantum key distribution (QKD) protocols require bright single-photon sources with a very low probability of multiphoton emission. In this work, we investigate single-photon generation from a negatively charged quantum dot embedded in an elliptical pillar microcavity, driven by either resonant excitation or adiabatic rapid passage (ARP). Our results show that the ARP excitation significantly suppresses multiphoton emission and improves photon indistinguishability compared to resonant excitation. We further evaluate the secure key rates of both BB84 and twin-field QKD (TF-QKD) using a quantum-dot single-photon source and compare its performance with that of Poisson-distributed sources (PDS), such as weak coherent pulses. The analysis reveals that the ARP provides a modest but consistent enhancement in secure key rate relative to resonant excitation. We show that quantum-dot single-photon sources offer improved performance compared to PDS sources at short and intermediate distances within the chosen parameter regime; however, at longer distances, PDS sources slightly surpass them in both decoy-state BB84 and TF-QKD under the same conditions.

Journal of the Optical Society of America B•Apr 1, 2026•0 citations

High-rate intercity quantum key distribution with a semiconductor single-photon source

Yang, Jingzhong, Jiang, Zenghui, Benthin, Frederik +13 more

Quantum key distribution (QKD) enables the transmission of information that is secure against general attacks by eavesdroppers. The use of on-demand quantum light sources in QKD protocols is expected to help improve security and maximum tolerable loss. Semiconductor quantum dots (QDs) are a promising building block for quantum communication applications because of the deterministic emission of single photons with high brightness and low multiphoton contribution. Here we report on the first intercity QKD experiment using a bright deterministic single photon source. A BB84 protocol based on polarisation encoding is realised using the high-rate single photons in the telecommunication C-band emitted from a semiconductor QD embedded in a circular Bragg grating structure. Utilising the 79 km long link with 25.49 dB loss (equivalent to 130 km for the direct-connected optical fibre) between the German cities of Hannover and Braunschweig, a record-high secret key bits per pulse of 4.8 × 10−5 with an average quantum bit error ratio of ~ 0.65% are demonstrated. An asymptotic maximum tolerable loss of 28.11 dB is found, corresponding to a length of 144 km of standard telecommunication fibre. Deterministic semiconductor sources therefore challenge state-of-the-art QKD protocols and have the potential to excel in measurement device independent protocols and quantum repeater applications.

•Jan 1, 2024•0 citations
We present the first demonstration of telecom fiber-based quantum key distribution using single photons from a quantum dot in a pillar microcavity. The source offers both telecommunication wavelength operation at 1.3 microns and Purcell enhancement of the spontaneous emission rate. Several emission lines from the InAs/GaAs quantum dot are identified, including the exciton-biexciton cascade and charged excitonic emission. We show an order of magnitude increase in the collected intensity of the emission from a charged excitonic state when temperature tuned onto resonance with the HE11 mode of the pillar microcavity, as compared to the off-resonance intensity. Above- and below-GaAs-bandgap optical excitation was used and the effect of the excitation energy on the photoluminescence investigated. Exciting below the GaAs-bandgap offers significant improvement in the quality of the single photon emission and a reduction of the multi-photon probability to 0.1 times the value for Poissonian light was measured, before subtraction of detector dark counts, the lowest value recorded to date for a quantum dot source at a fibre wavelength. We observe also the first evidence of Purcell enhancement of the spontaneous emission rate for a single telecommunication wavelength quantum dot in a pillar microcavity. We have incorporated the source into a phase encoded interferometric scheme implementing the BB84 quantum cryptography protocol and distributed a key, secure from the pulse splitting attack, over standard telecommunication optical fibre. We show a transmission distance advantage over that possible with (length-optimized) uniform intensity weak coherent pulses at 1310 nm in the same system.
We report the distribution of a cryptographic key, secure from photon number splitting attacks, over 35km of optical fiber using single photons from an InAs quantum dot emitting ∼1.3μm in a pillar microcavity. Using below GaAs-bandgap optical excitation, we demonstrate suppression of multiphoton emission to 10% of the Poissonian level without detector dark count subtraction. The source is incorporated into a phase encoded interferometric scheme implementing the BB84 protocol for key distribution over standard telecommunication optical fiber. We show a transmission distance advantage over that possible with (length-optimized) uniform intensity weak coherent pulses at 1310nm in the same system.
Quantum key distribution with single photons from a telecommunication-wavelength quantum dot source is performed over a standard optical fibre link. The source was operated at a temperature of 70 K and gave g(2)(0)~0.166 with an efficiency of 5% after coupling into the single-mode fibre. Correlation results are quoted without subtraction of detector dark counts and g(2)(0) as low as 0.1 was measured, at reduced efficiency. This source enabled a proof-of-principle demonstration of quantum key distribution over 35 km of fibre using the BB84 protocol and phase encoding.
A demonstration of the principles of quantum key distribution (QKD) is performed using a single-photon source in a proof of concept test-bed over a distance of 2 km in standard telecommunications optical fiber. The single-photon source was an optically-pumped quantum dot in a microcavity emitting at a wavelength of 895 nm. Characterization of the QKD parameters was performed at a range of different optical excitation powers. An investigation of the effect of varying the optical excitation power of the quantum dot microcavity on the quantum bit error rate and cryptographic key exchange rate of the system are presented.
Various quantum key distribution (QKD) protocols require bright single-photon sources with a very low probability of multiphoton emission. In this work, we investigate single-photon generation from a negatively charged quantum dot embedded in an elliptical pillar microcavity, driven by either resonant excitation or adiabatic rapid passage (ARP). Our results show that ARP excitation significantly suppresses multiphoton emission and improves photon indistinguishability compared to resonant excitation. We further evaluate the secure key rates of both BB84 and twin-field QKD (TF-QKD) using a quantum-dot single-photon source and compare its performance with that of Poisson-distributed sources (PDS), such as weak coherent pulses. The analysis reveals that ARP provides a modest but consistent enhancement in secure key rate relative to resonant excitation. We show that quantum-dot single-photon sources offer improved performance compared to PDS sources at short and intermediate distances within the chosen parameter regime; however, at longer distances, PDS sources slightly surpass them in both decoy-state BB84 and TF-QKD under the same conditions.
Various quantum key distribution (QKD) protocols require bright single-photon sources with a very low probability of multiphoton emission. In this work, we investigate single-photon generation from a negatively charged quantum dot embedded in an elliptical pillar microcavity, driven by either resonant excitation or adiabatic rapid passage (ARP). Our results show that the ARP excitation significantly suppresses multiphoton emission and improves photon indistinguishability compared to resonant excitation. We further evaluate the secure key rates of both BB84 and twin-field QKD (TF-QKD) using a quantum-dot single-photon source and compare its performance with that of Poisson-distributed sources (PDS), such as weak coherent pulses. The analysis reveals that the ARP provides a modest but consistent enhancement in secure key rate relative to resonant excitation. We show that quantum-dot single-photon sources offer improved performance compared to PDS sources at short and intermediate distances within the chosen parameter regime; however, at longer distances, PDS sources slightly surpass them in both decoy-state BB84 and TF-QKD under the same conditions.
Quantum key distribution (QKD) enables the transmission of information that is secure against general attacks by eavesdroppers. The use of on-demand quantum light sources in QKD protocols is expected to help improve security and maximum tolerable loss. Semiconductor quantum dots (QDs) are a promising building block for quantum communication applications because of the deterministic emission of single photons with high brightness and low multiphoton contribution. Here we report on the first intercity QKD experiment using a bright deterministic single photon source. A BB84 protocol based on polarisation encoding is realised using the high-rate single photons in the telecommunication C-band emitted from a semiconductor QD embedded in a circular Bragg grating structure. Utilising the 79 km long link with 25.49 dB loss (equivalent to 130 km for the direct-connected optical fibre) between the German cities of Hannover and Braunschweig, a record-high secret key bits per pulse of 4.8 × 10−5 with an average quantum bit error ratio of ~ 0.65% are demonstrated. An asymptotic maximum tolerable loss of 28.11 dB is found, corresponding to a length of 144 km of standard telecommunication fibre. Deterministic semiconductor sources therefore challenge state-of-the-art QKD protocols and have the potential to excel in measurement device independent protocols and quantum repeater applications.