Optimising physical parameters of a quantum network based on a loss-jitter trade-off

TL;DR

This paper tackles how to optimally configure quantum communication links by jointly selecting wavelength and signal bandwidth in the presence of loss, dispersion, and detector jitter. It uses a calibrated BBM92-based simulator to generate optimization mosaics that map the best wavelength–bandwidth combinations for single links and wavelength-multiplexed networks over SMF and NZDSF fibers. The findings show region-specific optima: C-Band often best for single links with typical jitter, O-Band beneficial only for short, low-jitter links, and multiplexed networks favor SMF/C-Band with modest bandwidths around 5–10 GHz, with NZDSF being advantageous only at extreme distances. The work provides a practical framework for deploying quantum networks on existing fibre infrastructure and highlights how tunable multiplexing and parameter optimization can meaningfully improve quantum key distribution performance in real networks.

Abstract

As quantum communication systems and networks are becoming a commercial reality, clarity on their future infrastructure is increasingly important. Based on the inevitable presence of some amount of loss, chromatic dispersion, and timing jitter, we present simulations to show that certain wavelengths and bandwidths have clear advantages.

Figures (6)

• Figure 1: The schematic for sharing in a source central entanglement distribution scheme. Here is any source of or entanglement, and is any system that can receive or perform quantum state measurements.
• Figure 2: The choice of bandwidth of transmitted photon that resulted in the highest secret key rate, against total measurement jitter and the transmission distance. a) shows the optimal selection for SMF fibre with 1550nm light. b) shows the optimal selection for SMF fibre with 1310nm light. c) shows the optimal selection for NZDSF fibre with 1550nm light. Here SMF is Corning SMF-28Ultra CorningUltra and NZDSF is Corning LEAF CorningLEAF.
• Figure 3: The choice of bandwidth of transmitted photon that resulted in the highest secret key rate per GHz of the bandwidth, against total measurement jitter and the transmission distance. a) shows SMF fibre with 1550nm light. b) shows SMF fibre with 1310nm light. c) shows NZDSF fibre with 1550nm light. Here SMF is Corning SMF-28Ultra CorningUltra and NZDSF is Corning LEAF CorningLEAF.
• Figure 4: The combined selection of optimal transmission wavelength, transmission medium, and linewidth that resulted in the highest secret key rate, against total measurement jitter and the transmission distance. Here SMF is Corning SMF-28Ultra CorningUltra and NZDSF is Corning LEAF CorningLEAF. within the SMF 1310nm section, the two dotted lines show the region where there is an improvement over SMF and NZDSF at 1550nm, but where the performance is worse than SMF 1310nm at the higher bandwidth.
• Figure S1: The simulation results based on combinations of inputs, showing the rate of correlations seen per pulse, here defined to be a discrete time width. a) shows the effect of increasing the *fwhm. b) shows the effect of increasing the attenuation of the link. c) shows the effect of a single mode fibre CorningUltra link combining both the increase of the fwhm and attenuation. Here the fibre has chromatic dispersion of 18psnmkm and attenuation of 0.18dBkm.