Stable Transmission of High-Dimensional Quantum States Over a 2-km Multicore Fiber

Abstract

High-dimensional quantum states have already settled their advantages in different quantum technology applications. However, their reliable transmission in fiber links remains an open challenge that must be addressed to boost their application, e.g. in the future quantum internet. Here, we prove how path encoded high-dimensional quantum states can be reliably transmitted over a 2 km long multicore fiber, taking advantage of a phase-locked loop system guaranteeing a stable interferometric detection.Index Terms-Quantum communication, quantum key distribution, high-dimensional path encoding, multicore fiber

High-Dimensional Pixel Entanglement: Efficient Generation and Certification

“…As a result, measurements in such bases maximize photon flux, are resistant to detector noise, and allow us to minimize the total number of measurements required. Second, as the distribution of macro-pixels is determined by circle packing formulas, this basis is compatible with state-of-the-art quantum communication technologies based on multi-core fibres [37][38][39][40] and was recently employed for high-dimensional entanglement transport through a commercial multi-mode fibre [41] as well as a test of genuine high-dimensional steering [42]. Third and most significantly, informed by knowledge of the JTMA, we can optimise this basis to approach a maximally entangled state of the form…”

Advances in Silicon Quantum Photonics

“…High-dimensional quantum key distribution has been recently demonstrated using a technologically similar approach: four-dimensional quantum states were transmitted over a few meters of multicore fiber [290], where different fiber cores corresponded to the different basis states of a photonic qudit. More recently, this transmission distance was extended to kilometer length scales using phaselocked loops [291], [292]. SNSPDs are among the most costly and least portable resource in quantum photonicstheir availability is often a bottleneck in quantum photonics research.…”

Characterization and stability measurement of deployed multicore fibers for quantum applications

“…Furthermore, MCFs represent a perfect match with photonic integrated circuits for multiple-input-multiple-output applications and are expected to be widely adopted in long-haul undersea connections [9]. Recently, MCFs have also been tested for quantum communication [10][11][12][13][14][15][16][17]. Thanks to their properties of low loss and small crosstalk between the different cores, these fibers, which are referred to as uncoupled-core MCFs, have been used for copropagating quantum and classical signals in different cores [10] or in the same core [11,12] and also for transmitting high-dimensional quantum states [13][14][15][16][17].…”

“…Recently, MCFs have also been tested for quantum communication [10][11][12][13][14][15][16][17]. Thanks to their properties of low loss and small crosstalk between the different cores, these fibers, which are referred to as uncoupled-core MCFs, have been used for copropagating quantum and classical signals in different cores [10] or in the same core [11,12] and also for transmitting high-dimensional quantum states [13][14][15][16][17]. High-dimensional quantum states, thanks to their intrinsic properties, allow for a higher information capacity (useful in the case of a limited photon budget or in the regime of saturating single-photon detectors) and also exhibit higher robustness to the noise affecting the quantum communication (which is critical in real-world applications) [18].…”