Photonic Circuits with Time Delays and Quantum Feedback

Quantum Random Walks Circuits with Photonic Waveguides

Arrays of 21 evanescently coupled waveguides are fabricated to implement quantum random walks and a generalized form of two-photon non-classical interference, which was observed via two photon correlation. Keywords-component; quantum optics; waveguides; quantum computing; quantum random walks.

Universal photonic quantum computation via time-delayed feedback.

We propose and analyze a deterministic protocol to generate two-dimensional photonic cluster states using a single quantum emitter via time-delayed quantum feedback. As a physical implementation, we consider a single atom or atom-like system coupled to a 1D waveguide with a distant mirror, where guided photons represent the qubits, while the mirror allows the implementation of feedback. We iden...

Laser written waveguide photonic quantum circuits.

We report photonic quantum circuits created using an ultrafast laser processing technique that is rapid, requires no lithographic mask and can be used to create three-dimensional networks of waveguide devices. We have characterized directional couplers--the key functional elements of photonic quantum circuits--and found that they perform as well as lithographically produced waveguide devices. W...

Phase-controlled integrated photonic quantum circuits.

Scalable photonic quantum technologies are based on multiple nested interferometers. To realize this architecture, integrated optical structures are needed to ensure stable, controllable, and repeatable operation. Here we show a key proof-of-principle demonstration of an externallycontrolled photonic quantum circuit based upon UV-written waveguide technology. In particular, we present non-class...

Feedback stabilization of discrete-time quantum systems subject to non-demolition measurements with imperfections and delays