Magiq Technologies, Inc.

Alexel Trifonov

Anton Zavriyev

Darius Subacius

A robust, quickly tunable narrow-linewidth entangled photon source system based on Spontaneous Parametric Down Conversion (SPDC) of the pump light in periodically polled LiNbO(PPLN) waveguides. The photon source provides narrow-linewidth, entangled output photons having a wavelength in the telecom C-Band wavelength. To tailor the output spectrum of the output photons, the PPLN waveguide is arranged between two end waveguides having LiNbO3-embedded Bragg gratings, thereby forming a tunable Fabry-Perot cavity. The resulting narrow output linewidth of the output photons makes the system desirable for use in a long-distance quantum key distribution (QKD) system.

Tunable compact entangled-photon source and QKD system using same

A one-way stabilized QKD system () that utilizes a control signal (CS) and a quantum signal (QS) that travel the same path through the system from a first QKD station (Alice) to a second QKD station (Bob). The control signal is detected at Bob and used to stabilize Bob's side of the interferometer against phase variations. The system also includes a polarization control stage () that controls (e.g., scrambles) the polarization of the photons entering Bob. The combination of the polarization control and the active phase stabilization of the interferometer at Bob's end allows for the stable operation of the interferometer when used as part of a one-way QKD system.

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Boston, MA, United States of America

Alexel Trifonov