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Generator for producing photon number state

A generation device and photon count technology, which can be applied to safety communication devices, optics, electromagnetic transmitters, etc., can solve the problems that multiple photons cannot be generated correctly, the timing of photons cannot be controlled, and the detector cannot detect the number of incident photons, etc.

Inactive Publication Date: 2004-05-05
MITSUBISHI ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0007] However, on the other hand, it is impossible to generate a "2-photon state" in which 2 photons continuously exist within the response time of the detector.
[0008] As mentioned above, in the prior art, since the detector cannot detect the number of incident photons, and does not have a mechanism for judging the number of incident photons, when the photon pairs occur continuously within the response time of the photon detector, will open the door and thus have the disadvantage of emitting a state containing 2 or more photons within the response time of the detector
[0009] In addition, in the conventional method, multiple photons cannot be accurately generated in one pulse
[0010] In addition, it is not possible to control the timing of the photon generation inside the pulse

Method used

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  • Generator for producing photon number state
  • Generator for producing photon number state
  • Generator for producing photon number state

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Embodiment 1

[0051] figure 1 is an overall structural diagram of an embodiment of the present invention. In this embodiment, it is a device that generates a single photon state in which two photons do not exist densely within the resolution time τ of the detector.

[0052] exist figure 1 Among them, 1 is a photon pair source that generates photon pairs that have a correlation relationship at the time of occurrence, 2 is a photon number detector that detects idle photons 5, and 3 is a control device that controls the gate device 4 according to the photon number information of the photon number detector . The gate device 4 controls the emission of signal photons 6 . Photon pair source 1 consists of a nonlinear optical medium 9 and a light source 7 of pumping light 8 pumping it. The idler photons 5 generated by the nonlinear optical medium 9 are focused onto the photon number detector 2 by the lens 15 through the optical filter 17 that selectively transmits the targeted idler photons. ...

Embodiment 2

[0067] In Example 1, the wavelength of the generated signal light is 702.2 nm, however, this wavelength can be arbitrarily changed by selecting an appropriate pumping light source laser and nonlinear optical medium. For example, it can occur at wavelengths around 1550 nm, around 1310 nm, and around 800 nm, which are generally used in communications using optical fibers.

[0068] Example 1 ( figure 2 The generation method of photon pairs shown in ) is suitable for obtaining photon pair beams with equal wavelength and small angular spread. However, for other purposes, photons with different wavelengths can also be obtained by changing the direction of the optical axis of the BBO crystal. right. At this time, figure 2 The two resonance curves are respectively tangent to the straight lines corresponding to different wavelengths. At this time, the extraction direction of the photon is given by figure 2 The resonance curves shown are taken at angles tangent to the straight li...

Embodiment 3

[0072] Other embodiments of the invention are shown in Figure 5 . In this embodiment, 7 is the pumping light source, 18 is the optical fiber that guides the pumping light, 19 is the waveguide nonlinear medium, and 20 is the fluorescence pair and the pumping light generated from the waveguide nonlinear optical medium 19. A waveguide filter for light, 21 is an exit port for pumping light, and 22 is a waveguide filter for dividing the fluorescent pair into two branches.

[0073] In this embodiment, the parametric fluorescence pair occurs in the waveguide type nonlinear optical medium 19 . Fluorescence pairs have longitudinal and transverse polarizations respectively, and in waveguide filter 22 operating as a polarized beam splitter, fluorescence having one of the polarizations is transmitted to the photon number detector, and the other is transmitted to the photon number detector. to fiber 10.

[0074] With such a structure, the device can be miniaturized, and optical adjustme...

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Abstract

An apparatus is provided for generating a predetermined number of photons, particularly one photon, at a definite time and at scheduled times for quantum communications. The apparatus comprises a source for generating a pair of photons including a signal photon and an idler photon that are mutually correlated in time of generation; a detector for measuring the number of idler photons; a control device for controlling a gate device according to the number of photons measured by the detector; and a gate device for controlling the emission of signal photons.

Description

technical field [0001] The present invention relates to a device that generates a certain number of photons with known occurrence times, and further relates to a device that generates a certain number of photons according to a known schedule. The above-mentioned fixed number which is particularly important is 1, which can be used in quantum cryptography communication and the like. Background technique [0002] In the quantum cryptography communication system, by making photons carry information one by one, the eavesdropper can be found according to the principle of quantum mechanics. However, if two or more photons carry the same information, the eavesdropper may use some of these photons, so that the existence of the eavesdropper cannot be detected. Thus, ideally, it would be necessary to use pulses containing at most 1 photon. As such a pulse, the light from the laser light source is usually attenuated by an attenuator so that the average number μ of photons per pulse is...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02F1/39H04L9/08
CPCH04L9/0883H04B10/50H04L9/0852G02F1/39
Inventor 竹内繁树
Owner MITSUBISHI ELECTRIC CORP
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