Quantum photonics often relies on nonlinear optics for the generation of photons, followed by reconfigurable linear optical networks for coherent control. In this talk, I will start by reviewing our study of multimode nonlinear optics in fibers [1,2], which also enabled our realization of an all-fiber entangled photon pairs source [3]. These photons are spatially entangled in the eigenmodes of the multimode fiber, allowing for high-dimensional quantum communications. I will then present a couple of methods to coherently control such states. The first is achieved by multiplane light conversion based on a spatial light modulator [4], while the second is by employing a “Fiber piano” [5], a piezo-actuator array that deforms the multimode fiber. Finally, I will introduce a novel Quantum Key Distribution protocol that utilizes high-dimensional encoding to boost the secure key rate and its experimental implementation in the Israeli Quantum Key Distribution National Demonstrator [6].

[1] Kfir Sulimany, et al. Physical Review Letters 121.13 (2018): 133902.

[2] Kfir Sulimany, et al. Optica 9.11 (2022): 1260-1267.

[3] Kfir Sulimany, and Yaron Bromberg. npj Quantum Information 8.1 (2022): 1-5.

[4] Ohad Lib, Kfir Sulimany, and Yaron Bromberg. Physical Review Applied 18.1 (2022): 014063.

[5] Zohar Finkelstein, Kfir Sulimany, et al. APL Photonics (2023): 8 (3): 036110.

[6] Kfir Sulimany, et al. arXiv preprint arXiv:2105.04733 (2021).