Multi-core fiber integrated multi-port beam splitters for quantum information processing

Abstract

Multi-port beam splitters are cornerstone devices for high-dimensional quantum information tasks, which can outperform the two-dimensional ones. Nonetheless, the fabrication of such devices has proven to be challenging with progress only recently achieved with the advent of integrated photonics. Here, we report on the production of highquality N × N (with N = 4, 7) multi-port beam splitters based on a new scheme for manipulating multi-core optical fibers. By exploring their compatibility with optical fiber components, we create four-dimensional quantum systems and implement the measurement-device-independent random number generation task with a programmable four-arm interferometer operating at a 2 MHz repetition rate. Due to the high visibilities observed, we surpass the one-bit limit of binary protocols and attain 1.23 bits of certified private randomness per experimental round. Our result demonstrates that fast switching, low loss, and high optical quality for high-dimensional quantum information can be simultaneously achieved with multi-core fiber technology.

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…”

Estimation of pure quantum states in high dimension at the limit of quantum accuracy through complex optimization and statistical inference

“…An experimental realization of the CSPSA-MLE method applied to state of a single 2-dimensional quantum system can be carried out with current experimental techniques 44 , 57 for generating and measuring single-photon polarization states. The higher dimensional case can be demonstrated by means of experimental setups based on single photons and concatenated spatial light modulators 32 , 60 , 61 or via integrated quantum photonics 62 , 63 . These two experimental platforms offer the possibility of performing electronically controlled adaptive measurements.…”

Multi-core Fiber Technology

“…temperature sensing to 1000°C using MCF optical sensors with a typical temperature sensitivity of 170 pm/°C Mach-Zehnder (MZ) interferometers may be fabricated by employing MCFs since the slopes of the resultant interference peaks are steeper. Until quite recently, many MCF optical sensors used inefficient methods to throw light into the multi-arm MZ, causing substantial losses for QI processing [41] use novel tapering methods to construct the multi-arm MZ directly into a specially built MCF.…”