California Institute of Technology

John G Bartholomew

Andrei Faraon

Jake Rochman

Jonathan M Kindem

Andrei Ruskuc

Tian Xie

Systems and methods for providing optical quantum communication networks based on rare-earth ion quantum bits (qubits) entrapped in solids are presented. According to one aspect a qubit is provided by anYbion doped into a YVO crystal structure. A nanophotonic cavity fabricated in the doped crystal structure provides a zero-field energy level structure of the ion with optical transitions between ground and excited states at a wavelength longer than 980 nm. A subspace of the qubit is provided by two lower energy levels at the ground states separated by a microwave frequency of about 675 MHz. Addressing of the optical transitions is via first and second lasers and addressing of microwave transitions at the ground and excited states are via respective microwave sources. A single-shot readout sequence of the qubit based on two consecutive readout sequences on the optical transitions separated by a microwave pumping of the ground states is presented. Assignment of a readout state is conditionally based on combined states detected in the two consecutive readout sequences.

Optical quantum networks with rare-earth ions

Systems and methods for providing a microwave-to-optical (M2O) transducer using magneto-optical field interactions with spin states of an ensemble of ions doped into a crystal structure is presented. According to one aspect, the crystal structure is a (Yb:YVO) doped crystal structure that provides a substrate for an on-chip implementation of the transducer. According to one aspect, coupling of microwave and optical signals to the ions is based on respective microwave and optical waveguides fabricated in or on the doped crystal structure. According to another aspect, coupling of microwave and optical signals to the ions is based on respective microwave and optical resonant cavities fabricated in or on the doped crystal structure. Transduction can be based on either a three-level system with near-zero applied external magnetic field or on a four-level system with zero applied external magnetic field. The transducer can operate reversibly as an optical-to-microwave (O2M) transducer.

Growing community of inventors

Camperdown, Australia

John G Bartholomew