Prof. Kumar's group spans classical and quantum optics across three inter-related areas: (1) Quantum Fiber Optics — generation and distribution of entanglement (photon-pair, multi-photon) over fiber networks, quantum key distribution, and first-ever quantum teleportation over active internet-carrying fiber; (2) Nonlinear Quantum Optics — squeezed light and twin-beam (two-mode squeezed) state generation via fiber-based four-wave mixing and χ⁽²⁾ processes, with applications to sub-shot-noise interferometry, quantum-enhanced imaging, and quantum communication; (3) Photon-entanglement-enhanced precision measurement and optical communications. AT&T Professor of Information Technology; INQUIRE Executive Committee member.