Heralded multi-wavelength single photon source generating system based on micro-ring cavity structure

Abstract

The invention provides an heralded multi-wavelength single photon source generating system based on a micro-ring cavity structure. The system comprises a pumping unit, an entangled photon pair generating unit, a wavelength division multiplexing unit and a heralding unit. A pulse laser of the pumping unit emits lasers, wherein the communication waveband of the pluse laser is 1550 m, and the pulse width near the wavelength of the lasers is t; the lasers form time-entangled pulse pairs with the time interval of T (T > t) through a Mach-Zehnder interferometer; the entangled pulse pairs are coupled into a micro-ring cavity with a high Q value of the entangled pair generating unit through optical fibers, and due to a third-order nonlinear action in the micro-ring cavity, time-entangled pumping optical pulses are converted into a large number of controllable multi-wavelength time-entangled photon pairs; the time-entangled photon pairs with different wavelengths are emitted from different outlets through the wavelength division multiplexing unit to reach the announcement unit; a plurality of single photon detectors of the announcement unit detect the responding conditions of idle light according to corresponding channels to herald the generation of signal single photons, and therefore the multi-wavelength single photons with communication wavebands are emitted.

Description

technical field [0001] The invention relates to the field of quantum information technology and nonlinear optics, and more specifically relates to an announced multi-wavelength single-photon source generation system based on a micro-ring cavity structure. Background technique [0002] A single photon source refers to a light source that emits only one photon at a certain moment, and is an important tool for studying quantum physics and quantum information technology. Single photon sources play an important role in the field of quantum information, especially in the fields of quantum communication and quantum computing, which require stable and high-speed single photon sources, so single photon sources are currently a research hotspot. In quantum communication experiments, people generally use the precise control of phase randomization to attenuate weakly coherent light as a quasi-single photon source (for example, monitor the output power and control the average number of ph...

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Problems solved by technology

Quantum point light sources are very close to ideal single photon sources, and have been used in quantum communication, but this method requires complex structures and extremely low temperatures (less than 10K)

And the collection efficiency is not high, it is difficult to efficiently couple with single-mode fiber

A near-ideal single photon source can be made by using a single atom or molecule trapped, but the trapping of a single atom or molecule is a complex technology, thus limiting its application

Another method is to use twin photon pairs with second-order nonlinear effects to detect the existence of one idler photon announcing the presence of another signal photon, but the generation of twin photon pairs is itself probabilistic and the announcement efficiency is low (less than 0.5) , in addition, it is difficult to efficiently couple this kind of single-photon source with single-mode fiber

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