Low-loss polarization-maintaining router for single and entangled photons at a telecom wavelength

Abstract

Photon polarization serves as an essential quantum information carrier in quantum information and measurement applications. Routing of arbitrarily polarized single photons and polarization-entangled photons is a crucial technology for scaling up quantum information applications. Here, we demonstrate a low-loss, noiseless, polarization-maintaining routing of arbitrarily polarized single photons and, crucially, multi-photon entangled states where the entanglement is encoded in orthogonal polarization bases, at the telecom L-band. Our interferometer-based router is constructed by optics with a low angle of incidence and cross-aligned electro-optic crystals, achieving the polarization-maintaining operation with a minimal number of optical components. We demonstrate the routing of arbitrarily-polarized heralded single photons with a 0.057 dB (1.3%) loss, a $>$ 22 dB switching extinction ratio, and $>$ 99% polarization process fidelity to ideal identity operation. Moreover, the high-quality router achieves the routing of two-photon N00N-type entangled states with a highly maintained interference visibility of $\approx$ 97%. The demonstrated router scheme preserving multi-photon polarization state paves the way toward polarization-encoded photonic quantum networks as well as multi-photon entanglement synthesis via spatial- and time-multiplexing techniques.

References in corpus (6)

• Optical Quantum Computing
• Beating the Standard Quantum Limit with Four Entangled Photons
• Entanglement-free Heisenberg-limited phase estimation
• Provably-Secure and High-Rate Quantum Key Distribution with Time-Bin Qudits
• Frequency-encoded photonic qubits for scalable quantum information processing
• Low-Loss Polarization-Maintaining Optical Router for Photonic Quantum Information Processing

Cited by in corpus (1)

• Highly Efficient and Broadband Optical Delay Line towards a Quantum Memory