The limits of multiplexing quantum and classical channels: Case study of a 2.5 GHz discrete variable quantum key distribution system

Abstract

Network integration of quantum key distribution is crucial for its future widespread deployment due to the high cost of using optical fibers dedicated for the quantum channel only. We studied the performance of a system running a simplified BB84 protocol at 2.5 GHz repetition rate, operating in the original wavelength band, the short O-band, when multiplexed with communication channels in the conventional wavelength band, and the short C-band. Our system could successfully generate secret keys over a single-mode fiber with a length of 95.5 km and with co-propagating classical signals at a launch power of 8.9 dBm. Furthermore, we discuss the performance of an ideal system under the same conditions, showing the limits of what is possible with a discrete variable system in the O-band. We also considered a short and lossy link with 51 km optical fiber resembling a real link in a metropolitan area network. In this scenario, we could exchange a secret key with a launch power up to 16.7 dBm in the classical channels.

Quantum MAC: Genuine Entanglement Access Control via Many-Body Dicke States

“…To this aim, we observe that in the context of the EAC, the distribution of both the entangled resources could take place sequentially or in batch. In other words, the two resources may be distributed according to a time division strategy or frequency division strategy [60], [61]. In both the cases, the analytical framework developed in the previous sections continue to holds.…”

Structural properties of graded In x Ga 1−x As metamorphic buffer layers for quantum dots emitting in the telecom bands

“…Semiconductor quantum dots (QDs) are the leading physical platform for on-demand generation of non-classical light due to their superior photonic properties, such as high emission rates and low multi-photon error rates [1][2][3]. However, transmitting non-classical light over large distances in fiber networks requires single-photon emission in the telecom O-band and C-band (1.3 and 1.5 µm, respectively), which is advantageous because of both low photon absorption and wave packet dispersion in preexisting fiber networks [4,5].…”

Deployed MDI-QKD and Bell-State Measurements Coexisting with Standard Internet Data and Networking Equipment

“…Coexistence of quantum signals and telecom signals is challenging, considering the large intensity difference and the general intolerance to noise by quantum receivers and detectors [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. The natural approach is to separate quantum signals from telecom signals with well-established wavelength division multiplexing (WDM) techniques.…”

“…Numerous quantum communication experiments have employed these techniques to demonstrate coexistence of quantum signals with conventional network data on the same fiber [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], however all have been demonstrations of prepare-and-measure (P&M) QKD, in which a transmitting network node (Alice) prepares a qubit state and transmits it to a receiving node (Bob) for detection. A drawback to these studies is that P&M quantum communication, while suitable for trusted node QKD [8,9], does not include important ingredients for future stages of the quantum Internet [1], e.g.…”