Large reconfigurable quantum circuits with SPAD arrays and multimode fibers
Adrian Makowski, Michał Dąbrowski, Ivan Michel Antolovic, Claudio Bruschini, Hugo Defienne, Edoardo Charbon, Radek Łapkiewicz, Sylvain Gigan
Abstract
Reprogrammable integrated optics provides a natural platform for tunable quantum photonic circuits, but faces challenges when high dimensions and high connectivity are involved. Here, we implement high-dimensional linear transformations on spatial modes of photons using wavefront shaping together with mode mixing in a multimode fiber, and measure photon correlations using a time-tagging single-photon avalanche diode (SPAD) array. Our demonstration of a generalization of a Hong-Ou-Mandel interference to 22 output ports shows the scalability potential of wavefront shaping in complex media in conjunction with SPAD arrays for implementing high-dimensional reconfigurable quantum circuits. Specifically, we achieved (80.5±6.8)% similarity for indistinguishable photon pairs and (84.9±7.0)% similarity for distinguishable photon pairs using 22 detectors and random circuits.