1109.1762 (Xiao-song Ma et al.)

A high-speed tunable beam splitter for feed-forward photonic quantum
information processing    [PDF]

Xiao-song Ma, Stefan Zotter, Nuray Tetik, Angie Qarry, Thomas Jennewein, Anton Zeilinger

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.

View original: http://arxiv.org/abs/1109.1762