arXiv:1003.4654 · Applied Physics Letters
Operating quantum waveguide circuits with superconducting single-photon detectors
Chandra M. Natarajan, Alberto Peruzzo, S. Miki, M. Sasaki, Z. Wang, B. Baek, S. Nam, Robert H. Hadfield, Jeremy L. O’Brien
Abstract
Advanced quantum information science and technology (QIST) applications place exacting demands on optical components. Quantum waveguide circuits offer a route to scalable QIST on a chip. Superconducting single-photon detectors (SSPDs) provide infrared single-photon sensitivity combined with low dark counts and picosecond timing resolution. In this study, we bring these two technologies together. Using SSPDs we observe a two-photon interference visibility of 92.3±1.0% in a silica-on-silicon waveguide directional coupler at λ=804 nm—higher than that measured with silicon detectors (89.9±0.3%). We further operated controlled-NOT gate and quantum metrology circuits with SSPDs. These demonstrations present a clear path to telecom-wavelength quantum waveguide circuits.