Performance of continuous variable quantum key distribution system at different detector bandwidth

Tang, Xinke; Kumar, Rupesh; Ren, Shengjun; Wonfor, A.; Penty, R.V.; White, IH

doi:10.1016/j.optcom.2020.126034

Cited by 14 publications

(6 citation statements)

References 35 publications

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“…Also, with the same sampling rate, the effective resolution bit number of ADC decreases with the increment of the ADC input frequency, specifically 1 bit of is lost for every doubling of the ADC input frequency 39 . Such can be evaluated as 27 , 40 where u = 1 for homodyne detection and u = 2 for heterodyne detection, is the signal pulse duration, is the full voltage range of the ADC, is Planck’s constant. is the laser frequency, is the gain factor of the transimpedance amplifier (TIA, V/A), is the photodiode responsivity (A/W), is the LO power at Bob, and is the effective number of bit of the ADC at our system pulse rate.…”

Section: Methodsmentioning

confidence: 99%

“…The electronic to shot noise ratio should be low enough to achieve a precise quantum signal detection. The electronic noise in shot noise unit at the inputs of detectors can be expressed as 27 , 40 : where B is the bandwidth of the detector, which is chosen to be in our system, is the noise equivalent power of the BHD at B, and is the rate of incoming signals interfering with LO, which is equivalent to pulse generation rate in this system. The electronic noise increases with system repetition rate, but it can be improved with an increased LO power.…”

Section: Methodsmentioning

confidence: 99%

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Demonstration of high-speed and low-complexity continuous variable quantum key distribution system with local local oscillator

Ren

Yang

Wonfor

et al. 2021

Sci Rep

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We present an experimental demonstration of the feasibility of the first 20 + Mb/s Gaussian modulated coherent state continuous variable quantum key distribution system with a locally generated local oscillator at the receiver (LLO-CVQKD). To increase the signal repetition rate, and hence the potential secure key rate, we equip our system with high-performance, wideband devices and design the components to support high repetition rate operation. We have successfully trialed the signal repetition rate as high as 500 MHz. To reduce the system complexity and correct for any phase shift during transmission, reference pulses are interleaved with quantum signals at Alice. Customized monitoring software has been developed, allowing all parameters to be controlled in real-time without any physical setup modification. We introduce a system-level noise model analysis at high bandwidth and propose a new ‘combined-optimization’ technique to optimize system parameters simultaneously to high precision. We use the measured excess noise, to predict that the system is capable of realizing a record 26.9 Mb/s key generation in the asymptotic regime over a 15 km signal mode fibre. We further demonstrate the potential for an even faster implementation.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Demonstration of high-speed and low-complexity continuous variable quantum key distribution system with local local oscillator

Ren

Yang

Wonfor

et al. 2021

Sci Rep

View full text Add to dashboard Cite

show abstract

“…However, we stress that the computed secret key rates R are merely upper bounds for realistically achievable rates. Existing telecom QKD implemen-tations reach secure key rates up to a few Mbits per second [51][52][53]. Aside from finite quantum detection efficiencies and bandwidths, practical secret key rates are also limited by various factors such as actual experimental repetition rates [7], device-induced noise [52], finite size effects [22], or post-processing [54].…”

Section: B Comparison Between Telecom and Microwave Frequencymentioning

confidence: 99%

“…Existing telecom QKD implemen-tations reach secure key rates up to a few Mbits per second [51][52][53]. Aside from finite quantum detection efficiencies and bandwidths, practical secret key rates are also limited by various factors such as actual experimental repetition rates [7], device-induced noise [52], finite size effects [22], or post-processing [54]. Nevertheless, the demonstrated results make MQC relevant for short-distance classical communication protocols such as Wifi 802.11 standard (maximal communication distance 70 m), Bluetooth 5.0 ( 240 m), or more recent technologies such as 5G ( 305 m) because of matching frequency ranges, distances, and technological infrastructure.…”

Section: B Comparison Between Telecom and Microwave Frequencymentioning

confidence: 99%

Perspectives of microwave quantum key distribution in open-air

Fesquet¹,

Kronowetter²,

Renger³

et al. 2022

Preprint

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One of the cornerstones of quantum communication is the unconditionally secure distribution of classical keys between remote parties. This key feature of quantum technology is based on the quantum properties of propagating electromagnetic waves, such as entanglement, or the no-cloning theorem. However, these quantum resources are known to be susceptible to noise and losses, which are omnipresent in open-air communication scenarios. In this work, we theoretically investigate the perspectives of continuous-variable open-air quantum key distribution at microwave frequencies. In particular, we present a model describing the coupling of propagating microwaves with a noisy environment. Using a protocol based on displaced squeezed states, we demonstrate that continuous-variable quantum key distribution with propagating microwaves can be unconditionally secure at room temperature up to distances of around 200 meters. Moreover, we show that microwaves can potentially outperform conventional quantum key distribution at telecom wavelength at imperfect weather conditions.

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“…(1), or using low noise electronic components at the expense of the reduction in the bandwidth. In a homodyne detector, the bandwidth, B , and electronic noise variance, V ele , are related by the following equation [18].

V_{e l e} = \frac{N E P^{2} B τ}{h ν I_{l o}}

where, NEP is the sum of the noise‐equivalent power of the photo‐diodes and the amplifier, τ is the LO pulse width, h is Planck's constant and ν is the optical LO frequency.…”

Section: Homodyne Detector With Large Area Photo‐diodesmentioning

confidence: 99%

Increasing the Link‐distance of Free‐space Quantum Coherent Communication with Large Area Detectors

Kumar

Konieczniak

Bonner

et al. 2021

IET Quantum Communication

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A large area photo‐diode based homodyne detector for free‐space quantum coherent communication is reported. The detector's performance is studied in terms of the detection bandwidth and electronic noise for shot‐noise limited quantum signal detection. Using large area photo‐diodes increases the signal collection efficiency from turbulent atmospheric channels, in comparison with thetypical fibre‐based free‐space homodyne detectors. Under identical atmospheric turbulence and receiver aperture conditions, over a 700‐km free‐space link at 90° elevation angle, our homodyne detector based on a diameter of 1mm photo‐diode experiences 0dB loss due to turbulence, while a 10‐um fibre‐based detector experiences 13.5dB of signal loss.

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Performance of continuous variable quantum key distribution system at different detector bandwidth

Cited by 14 publications

References 35 publications

Demonstration of high-speed and low-complexity continuous variable quantum key distribution system with local local oscillator

Demonstration of high-speed and low-complexity continuous variable quantum key distribution system with local local oscillator

Perspectives of microwave quantum key distribution in open-air

Increasing the Link‐distance of Free‐space Quantum Coherent Communication with Large Area Detectors

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