Method and device for manufacturing external modulation high-speed decoy-state quantum light sources

Abstract

The invention discloses a method and a device for manufacturing external modulation high-speed decoy-state quantum light sources. The method includes enabling an ultra-short pulse laser device to emit linearly polarized light pulses with high repetition frequencies; transmitting the linearly polarized light pulses into a high-speed light intensity modulation module; randomly modulating light pulse signals with originally identical intensities to obtain light pulse signals with different light intensities; transmitting the light pulse signals in signal states and decoy states into a polarization state generating light path to randomly generate light in four polarization states; attenuating the light by a light attenuator and then outputting light in nine quantum states. The light in the nine quantum states can have three light intensities and four polarization states. The device comprises the ultra-short pulse laser device, the high-speed light intensity modulation module, the polarization state generating light path, a high-speed light phase modulation module, the light attenuator and a high-speed logic control chip. The method and the device have the advantages that the intensities of the light pulses are externally modulated, the modulated light pulses in the different quantum states are excellent in consistency, and accordingly the problem of security vulnerability due to inconsistency in the shapes, the amplitude and the pulse widths of existing light pulses which are internally modulated can be solved.

Description

technical field [0001] The invention relates to the field of quantum secure communication, which is used as a quantum state light source in a high-speed quantum key distribution system, in particular to a preparation method and device for an externally modulated high-speed decoy state quantum light source. Background technique [0002] Since the establishment of quantum mechanics at the beginning of the last century, it has greatly promoted the development of physics. Not only that, people found that the combination of quantum mechanics and information disciplines, the developed quantum information disciplines can complete tasks that classical information disciplines cannot complete, such as quantum key distribution (QKD), its security is guaranteed by the basic principles of physics, so this communication method has absolute security that cannot be cracked. [0003] At present, the widely recognized quantum key distribution schemes in the world include phase encoding scheme...

AI Technical Summary

Problems solved by technology

In order to realize the decoy state light source, the light output by each laser needs to be split to achieve the decoy state and the signal state respectively, which undoubtedly increases the redundancy and cost of the system, which is not conducive to the integration of the system; and because different laser diodes There are certain differences in the center wavelength and line width of the system, which will bring loopholes to the entire system.

[0008] It is also possible to use the internal modulation method to prepare three quantum states with different average photons per pulse in the decoy state, that is, to control the amplitude of the output laser pulse by controlling the amplitude of the electrical pulse signal driving the laser diode. This method drives the laser diode The electrical pulse signal is an ultra-short electrical pulse, and it is an AC signal. There is a certain negative bias voltage, which can be used in the middle and low frequency bands, but at high frequencies, especially when the frequency reaches GHz or above, this negative bias voltage exists. The biased electrical pulse signal will cause a series of inconsistencies in the shape, amplitude, and pulse width of the output laser pulse, which will cause security holes in the communication process

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