Quantum key distribution for 10 Gb/s dense wavelength division multiplexing networks

Abstract

Abstract:We demonstrate quantum key distribution (QKD) with bidirectional 10 Gb/s classical data channels in a single fiber using dense wavelength division multiplexing. Record secure key rates of 2.38 Mbps and fiber distances up to 70 km are achieved. Data channels are simultaneously monitored for error-free operation. The robustness of QKD is further demonstrated with a secure key rate of 445 kbps over 25 km, obtained in the presence of data lasers launching conventional 0 dBm power. We discuss the fundamental limit for the QKD performance in the multiplexing environment.

Ultimate capacity of a linear time-invariant bosonic channel

“…Our numerical work provides a comparison between the optimum-reception capacity, for a representative candidate filter, with corresponding results for heterodyne and homodyne detection over the same channel. Although carried out for single-wavelength operation with fiber propagation in mind, our results can easily be extended to the multiwavelength case of DWDM transmission [19,20,26,27]. Likewise, our single unit-cell evaluations can easily be extended to treat a chain of such unit cells.…”

Crosstalk Reduction in Hybrid Quantum-Classical Networks

“…In this case, the received power is guaranteed to be -25 dBm. This value is matched with the receiver sensitivity of -28 dBm for BER < 10 −12 , after considering 3 dB of safety margin [19]. The fiber attenuation coefficient, α, is assumed to be 0.2 dB/km.…”

“…Moreover, time-gating the detectors, i.e., only activating the photodetectors when a signal is present, further reduces the background photon count. In [18], [19], NBFs with bandwidths as low as 70 GHz and 15…”

“…Another effective method is the optimization of the launch power at the classical transmitters to meet the receiver sensitivity requirements for a target bit error rate (BER). Using such techniques, the simultaneous operation of several data channels alongside a single quantum channel has been experimentally demonstrated [17]- [19]. In this paper, we generalize such setups by considering a DWDM system that exploits its full range of available channels.…”

“…Another source of crosstalk is the power leakage from nearby data channels onto the QKD ones, which can occur due to the nonideal operation of DWDM multiplexers and demultiplexers. One conventional approach to reduce such a background noise is the usage of filtering techniques in frequency and time domains [18], [19]. Another effective method is the optimization of the launch power at the classical transmitters to meet the receiver sensitivity requirements for a target bit error rate (BER).…”