title: A high-speed tunable beam splitter for feed-forward photonic quantum information processing.
abstract: We realize quantum gates for path qubits with a high-speed, polarization-independent and tunable beam splitter. Two electro-optical modulators act in a Mach-Zehnder interferometer as high-speed phase shifters and rapidly tune its splitting ratio. We test its performance with heralded single photons, observing a polarization-independent interference contrast above 95%. The switching time is about 5.6 ns, and a maximal repetition rate is 2.5 MHz. We demonstrate tunable feed-forward operations of a single-qubit gate of path-encoded qubits and a two-qubit gate via measurement-induced interaction between two photons.
authors: Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria. xiaosong.ma@univie.ac.at
authors: Xiao-Song
authors: XS
authors: Ma
authors: Stefan
authors: S
authors: Zotter
authors: Nuray
authors: N
authors: Tetik
authors: Angie
authors: A
authors: Qarry
authors: Thomas
authors: T
authors: Jennewein
authors: Anton
authors: A
authors: Zeilinger