Science Daily October 13, 2022
An international team of researchers (USA – Oak Ridge National Laboratory, Purdue University, industry, Switzerland) combined state-of-the-art frequency-bin production with state-of-the-art light sources to develop an effective technique to characterize high-dimensional qudit entanglement. They fully characterized an entangled pair of eight-level qudits, which formed a 64-dimensional quantum space — quadrupling the previous record for discrete frequency modes. The researchers began their experiments by shining a laser into a micro-ring resonator — a circular, on-chip device fabricated and designed to generate nonclassical light. This powerful photon source which took 1 square millimeter of space and allowed the team to generate frequency-bin pairs in the form of quantum frequency combs. They used an electro-optic phase modulator to mix different frequencies of light and a pulse shaper to modify the phase of these frequencies. They captured many different frequency correlations. They developed a data analysis tools to work backward and infer which quantum states produced frequency correlations ideal for qudit applications. By sending signals through optical fiber, they aim to test quantum communication protocols such as teleportation, and entanglement swapping. According to the researchers they can perform other application-oriented experiments…read more. Open Access TECHNICAL ARTICLE
Evolution of the estimated state for the PPLN BFC. Credit: Nature Communications volume 13, Article number: 4338 (2022)Â