Novel entanglement source generation device and preparation method thereof

Abstract

The present invention provides a novel entanglement source generation device and a preparation method thereof, the spontaneous parametric down-conversion process is realized by utilizing the periodically poled lithium niobate film ridge waveguide, and the entanglement source is collected by virtue of the single-mode optical fiber, so that a fundamental mode matched with the single-mode optical fiber is allowed to be output in the spontaneous parametric down-conversion process; and the entanglement source is coupled into the single-mode optical fiber in a mode matching manner by virtue of a spatial light path, so that the entanglement source with high efficiency, high brightness and high quality is realized by virtue of extremely high single-mode coupling efficiency. Meanwhile, in the scheme for preparing the entanglement source through the optical fiber / waveguide-space-optical fiber coupling mode, high coupling, interference and filtering efficiency can be achieved in a simple and mature mode, and the quality of the entanglement source is further improved.

Description

technical field [0001] The invention relates to the fields of quantum optics and quantum information, in particular to a high-efficiency entanglement source generating device and a preparation method. Background technique [0002] The generation of two-photon entangled states in optical systems is generally based on nonlinear effects in nonlinear crystals, waveguides, or optical fibers, through processes such as spontaneous parameters to generate correlated photon pairs and further interfere to generate entanglement. The preparation of entanglement sources based on the spontaneous parameter conversion process of nonlinear crystals is a relatively common preparation method, and the crystals usually use BBO crystals, periodically poled crystals such as periodically poled potassium titanyl phosphate (PPKTP), and periodically poled lithium niobate (PPLN). crystals etc. [0003] The spontaneous parametric down conversion (SPDC) process in nonlinear crystals is the most mature me...

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Problems solved by technology

The inventor found through research that in the current entanglement source preparation scheme, there is still room for improvement in its overall preparation efficiency. For example, under the pure optical fiber optical path structure, its coupling, interference and filtering efficiencies are all limited and at a low level, resulting in The overall preparation efficiency is not high; under the pure spatial optical path structure of the crystal, there is a limitation in the collection efficiency of the entanglement source, resulting in a low overall preparation efficiency

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