CN115801255A - Quantum key distribution method, transmitting terminal and quantum key distribution system - Google Patents
Quantum key distribution method, transmitting terminal and quantum key distribution system Download PDFInfo
- Publication number
- CN115801255A CN115801255A CN202310081884.7A CN202310081884A CN115801255A CN 115801255 A CN115801255 A CN 115801255A CN 202310081884 A CN202310081884 A CN 202310081884A CN 115801255 A CN115801255 A CN 115801255A
- Authority
- CN
- China
- Prior art keywords
- optical
- light
- input
- pulse
- light intensity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Optical Communication System (AREA)
Abstract
The invention provides a quantum key distribution method, a transmitting end and a quantum key distribution system, wherein optical interference and light intensity marking are carried out on optical pulses input by the same group of pulse lasers through an optical interference structure, light intensity marking information is output to a receiving end, the optical pulses after different groups of interference are input to a polarization beam combiner and then input to a rear optical fiber structure, the rear optical fiber structure is used for processing and measuring the polarization state of the input optical pulses, and the obtained optical pulses with single photon magnitude and polarization state information are output to the receiving end, so that the receiving end processes the optical pulses with the single photon magnitude based on the optical pulses with the light intensity and the polarization state meeting the protocol requirements, and the key is encoded on an optical quantum without modulation at the transmitting end, namely, on-chip high-speed modulation is avoided; meanwhile, the light interference structure and the polarization beam combiner are arranged on the chip, so that the cost and the volume of the transmitting end and the quantum key distribution system where the transmitting end is located are reduced.
Description
Technical Field
The invention relates to the technical field of quantum information, in particular to a quantum key distribution method, a transmitting terminal and a quantum key distribution system.
Background
Quantum cryptographic communication is secret communication independent of algorithm complexity achieved by combining 'one-time pad' encryption technology and a physical principle for guaranteeing the safety of remote key agreement. In quantum cryptography communication, distribution is generally performed by a quantum key distribution system.
Quantum key distribution systems typically comprise a transmitting end for encoding a key on a light quantum and a receiving end for decoding and measuring the light quantum. Because the optics and electronics in the transmitting end of the existing quantum key distribution system are realized based on discrete optical components and PCB circuit boards, the cost is higher and the volume is larger.
Therefore, there is a need for a transmitting end that can encode a secret key on a light quantum and reduce the cost and volume of the existing quantum key distribution system.
Disclosure of Invention
In view of this, embodiments of the present invention provide a quantum key distribution method, an emitter, and a quantum key distribution system, so as to achieve the purposes of encoding a key on a light quantum and reducing the cost and volume of the existing quantum key distribution system.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
the first aspect of the embodiments of the present invention discloses a transmitting end for quantum key distribution, where the transmitting end includes: the device comprises a pulse laser, an optical interference structure, a polarization beam combiner and a rear optical fiber structure;
the optical interference structure and the polarization beam combiner are arranged on a chip;
the pulse laser is used for generating optical pulses;
the optical interference structure consists of a 50;
the four input ends of the optical interference structure are respectively connected with different pulse lasers, two output ends of different groups are respectively connected with one input end of the polarization beam combiner, the other two output ends of the optical interference structure are respectively connected with the high-speed photoelectric detector, the optical interference structure is used for respectively carrying out optical interference on the optical pulses input based on the input ends of the same group to obtain two groups of interfered optical pulses, the different groups of interfered optical pulses are input into the polarization beam combiner, the high-speed photoelectric detectors are used for detecting the light intensity of the two groups of interfered optical pulses and carrying out light intensity marking, and the obtained light intensity marking information is output to a receiving end, wherein the information contained in the same group of interfered optical pulses is the same;
the output end of the polarization beam combiner is connected with the input end of the rear optical fiber structure, and the polarization beam combiner is used for combining the input optical pulses according to a set polarization state and inputting the obtained optical pulses to the rear optical fiber structure;
the rear optical fiber structure is used for carrying out attenuation processing and polarization state measurement on the input optical pulse according to the set single photon magnitude, and outputting the obtained single photon magnitude optical pulse and polarization state information to the receiving end.
Optionally, the 50.
Optionally, the optical interference structure specifically includes: a first 50;
a first light inlet of the first 50;
the first 50;
the first high-speed photoelectric detector is used for detecting the light intensity of the input second light pulse, marking the light intensity and outputting light intensity marking information to the receiving end;
a first light inlet of the second 50;
the second 50;
and the second high-speed photoelectric detector is used for detecting the light intensity of the input fourth light pulse, marking the light intensity and outputting the obtained light intensity marking information to the receiving end.
Optionally, the rear optical fiber structure includes:
the device comprises a light beam splitter, a polarization analysis module and a light attenuation module;
the light beam splitter is used for splitting light pulses input by the polarization beam combiner according to a specific light energy proportion, inputting one group of split light pulses into the polarization analysis module and inputting the other group of split light pulses into the light attenuation module;
the polarization analysis module is used for measuring the polarization state of the input light pulse and outputting the obtained polarization state information to the receiving end;
the light attenuation module is used for carrying out attenuation processing on the input light pulse according to the set single-photon magnitude to obtain the light pulse of the single-photon magnitude.
Optionally, the optical splitter includes a 90.
Optionally, any one or more of the pulse laser, the optical beam splitter, the polarization analysis module, and the optical attenuation module is disposed on the chip.
Optionally, the polarization beam combiner includes a two-dimensional grating;
the first incident end of the two-dimensional grating is connected with the upper end of the output end of one group of output ends of the optical interference structure, the second incident end of the two-dimensional grating is connected with the lower end of the output end of the other group of output ends of the optical interference structure, the emergent end of the two-dimensional grating is connected with the input end of the rear optical fiber structure, and the two-dimensional grating is used for combining input optical pulses according to a set polarization state and inputting the obtained optical pulses to the rear optical fiber structure.
The second aspect of the present invention discloses a quantum key distribution method, which is applied to the transmitting end disclosed in the first aspect of the present invention, and the transmitting end includes: the optical fiber laser comprises a pulse laser, an optical interference structure, a polarization beam combiner and a rear optical fiber structure, wherein the method comprises the following steps:
the pulse laser generates light pulse and inputs the light pulse to the light interference structure;
the optical interference structure performs optical interference on input optical pulses based on the same group of input ends to obtain two groups of interfered optical pulses, inputs the different groups of interfered optical pulses to the polarization beam combiner, detects the light intensity of the two groups of interfered optical pulses by using the high-speed photoelectric detector, marks the light intensity, and outputs the obtained light intensity mark information to the receiving end, wherein the information contained in the same group of interfered optical pulses is the same;
the polarization beam combiner combines the input optical pulses according to a set polarization state, and inputs the obtained optical pulses to the rear optical fiber structure;
the rear optical fiber structure performs attenuation processing and polarization state measurement on the input optical pulse according to the set single photon magnitude, and outputs the obtained single photon magnitude optical pulse and polarization state information to the receiving end.
Optionally, when the optical interference structure specifically includes: when the first 50:
the first 50;
the first high-speed photoelectric detector detects the light intensity of the input second light pulse, marks the light intensity and outputs the obtained light intensity marking information to the receiving end;
the second 50;
and the second high-speed photoelectric detector detects the light intensity of the input fourth light pulse, marks the light intensity and outputs the obtained light intensity marking information to the receiving end.
The third aspect of the embodiments of the present invention discloses a quantum key distribution system, including: the first aspect of the embodiments of the present invention discloses a transmitting end and a receiving end.
Based on the quantum key distribution method, the transmitting end and the quantum key distribution system provided by the embodiment of the invention, the transmitting end comprises: the device comprises a pulse laser, an optical interference structure, a polarization beam combiner and a rear optical fiber structure; the optical interference structure and the polarization beam combiner are arranged on a chip; the pulse laser is used for generating optical pulses; the optical interference structure consists of a 50; the four input ends of the optical interference structure are respectively connected with different pulse lasers, two output ends of different groups are respectively connected with one input end of the polarization beam combiner, the other two output ends of the optical interference structure are respectively connected with the high-speed photoelectric detector, the optical interference structure is used for respectively carrying out optical interference on the optical pulses input based on the input ends of the same group to obtain two groups of interfered optical pulses, the different groups of interfered optical pulses are input into the polarization beam combiner, the high-speed photoelectric detector is used for detecting the light intensity of the two groups of interfered optical pulses and carrying out light intensity marking, and the obtained light intensity marking information is output to a receiving end, wherein the information contained in the optical pulses after the interference of the same group is the same; the output end of the polarization beam combiner is connected with the input end of the rear optical fiber structure, and the polarization beam combiner is used for combining the input optical pulses according to a set polarization state and inputting the obtained optical pulses to the rear optical fiber structure; the post-positioned optical fiber structure is used for carrying out attenuation processing and polarization state measurement on the input optical pulse according to the set single-photon magnitude, and outputting the obtained optical pulse with the single-photon magnitude and polarization state information to the receiving end.
In the embodiment of the invention, the light interference structure is used for carrying out light interference and light intensity marking on the light pulses input by the same group of pulse lasers, the light intensity marking information is output to the receiving end, the light pulses after different groups of interference are input to the polarization beam combiner, the polarization beam combiner combines the input light pulses after different groups of interference according to the polarization state and then inputs the light pulses to the post-positioned optical fiber structure, the post-positioned optical fiber structure is used for processing and measuring the polarization state of the input light pulses, and the obtained light pulses with single photon magnitude and the polarization state information are output to the receiving end, so that the single photon receiving end can process the received light pulses with magnitude based on the light intensity marking information and the polarization state information, and the key can be coded on a light quantum without being modulated at the transmitting end, namely, the on-chip high-speed modulation is avoided; meanwhile, the optical interference structure and the polarization beam combiner are arranged on the chip, so that the transmitting end does not need to be completely realized based on discrete optical components and PCB (printed Circuit Board), the cost and the volume of the transmitting end are reduced, and the cost and the volume of a quantum key distribution system where the transmitting end is located are further reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an emitting end for quantum key distribution according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of another transmitting end for quantum key distribution according to an embodiment of the present invention;
fig. 11 is a flowchart of a quantum key distribution method according to an embodiment of the present invention;
fig. 12 is a flowchart of another quantum key distribution method according to an embodiment of the present invention;
fig. 13 is a schematic structural diagram of a quantum key distribution system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
Quantum key distribution systems typically comprise a transmitting end for encoding a key on a light quantum and a receiving end for decoding and measuring the light quantum. Therefore, for the transmitting end of the quantum key distribution system, it is generally necessary to modulate the light quantum into different states by using modulation means such as phase modulation or polarization modulation, and the different light quantum states represent different encoded information.
For the transmitting end of the quantum key distribution system, the encoding of the intensity and polarization states of the quantum states is required. For the polarization encoding of the quantum state, according to a specific operating communication protocol, such as a BB84 protocol, a six-state protocol, a reference system independent protocol, and the like, it is necessary to randomly prepare a plurality of polarization states among a horizontal polarization state, a vertical polarization state, a + 45-degree polarization state, a-45-degree polarization state, a left-handed circular polarization state, and a right-handed circular polarization state; for the intensity of quantum state light, it is generally necessary to prepare a compound having a photon number of 0,μ 1 Andμ 2 these three photon number states (by adjusting the intensity of the light pulse) are randomly generated and the photon number state and the polarization state need to be randomly combined.
Therefore, if one transmitting end can meet the quantum state preparation conditions, the key can be encoded on the light quantum.
Fig. 1 is a schematic structural diagram of a transmitting end for quantum key distribution, provided in an embodiment of the present invention, where the transmitting end includes: the device comprises a first pulse laser 1, a second pulse laser 2, a third pulse laser 3, a fourth pulse laser 4, an optical interference structure 5, a polarization beam combiner 6 and a rear optical fiber structure 7.
The optical interference structure 5 and the polarization beam combiner 6 are disposed on a chip.
The material of the chip can be common optical chip material such as silicon-on-insulator (SOI), indium phosphide (InP) and the like.
In one embodiment of the present invention, one or more of the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, and the fourth pulse laser 4 may be disposed on a chip.
Specifically, when the optical interference structure 5 and the polarization beam combiner 6 are disposed on an optical chip of indium phosphide (InP), one or more of the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, and the fourth pulse laser 4 are disposed on the optical chip of indium phosphide (InP).
The first pulse laser 1, the second pulse laser 2, the third pulse laser 3 and the fourth pulse laser 4 are used for generating optical pulses and outputting the optical pulses through an output end.
It should be noted that, since the pulse laser needs an operating current to directly adjust the light state, that is, the gain of the pulse laser is controlled by continuously injecting periodic current signals at equal intervals, so that the pulse laser can continuously generate light pulses at a specific period. Thus, in this mode of operation, each optical pulse output by the pulsed laser is set up by the semiconductor spontaneous emission process, resulting in a random phase of each optical pulse but substantially the same optical intensity.
That is, the light pulses generated by the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, and the fourth pulse laser 4 are light pulses having random phases and the same light intensity.
The optical interference structure 5 is composed of a 50.
Depending on the material of the chip on which the optical interference structure 5 is located, the 50.
In one embodiment of the present invention, the 50.
The high-speed photodetector in the optical interference structure 5 may be a PIN structure.
The optical interference structure 5 comprises two sets of inputs and two opposing sets of outputs, each set of inputs comprising two inputs and each set of outputs comprising two outputs.
The four input ends of the optical interference structure 5 are respectively connected to different pulse lasers, that is, the four input ends of the optical interference structure 5 are respectively connected to the first pulse laser 1, the second pulse laser 2, the third pulse laser 3 and the fourth pulse laser 4. For receiving the optical pulses with random phases and the same optical intensity generated by the first pulse laser 1, the second pulse laser 2, the third pulse laser 3 and the fourth pulse laser 4.
Wherein different pulsed lasers and the optical interference structure 5 may be connected by waveguides.
Two output ends of different groups of the optical interference structure 5 are respectively connected with one input end of the polarization beam combiner 6, and the other two output ends are respectively connected with a high-speed photoelectric detector.
That is, one output end of a group of output ends of the optical interference structure 5 is connected with one input end of the polarization beam combiner 6, and the other output end is connected with a high-speed photodetector.
One output end of the other group of output ends of the optical interference structure 5 is connected with one input end of the polarization beam combiner 6, and the other output end is connected with a high-speed photoelectric detector.
The optical interference structure 5 is configured to perform optical interference on optical pulses input based on the same group of input terminals, respectively, to obtain two groups of interfered optical pulses with random phases and random light intensities.
That is, the optical interference structure 5 is configured to perform optical interference on optical pulses with random phases and the same optical intensity input by the first pulse laser 1 and the second pulse laser 2 to obtain a group of interfered optical pulses with random phases and random optical intensities, and the optical interference structure 5 is configured to perform optical interference on optical pulses with random phases and the same optical intensity input by the third pulse laser 3 and the fourth pulse laser 4 to obtain another group of interfered optical pulses with random phases and random optical intensities.
Wherein, the information contained in the same group of interfered light pulses is the same.
Further, the optical interference structure 5 inputs different groups of interfered optical pulses to the polarization beam combiner 6 from two input ends of the polarization beam combiner 6, detects the light intensities of the two groups of interfered optical pulses by using the high-speed photodetector, performs light intensity labeling, and outputs obtained light intensity labeling information to the receiving end.
Specifically, the high-speed photodetector measures the light intensity of the input light pulse to obtain the light intensity of the light pulse, marks the light intensity to obtain light intensity marking information for marking the light intensity of the light pulse, and outputs the light intensity marking information to the receiving end.
For example, the high-speed photodetector detects that the light intensity of the input light pulse is w1, w1 or w3, marks the light pulse and the light intensity thereof to obtain light intensity mark information of the corresponding light pulse, and outputs the light intensity mark information to the receiving end. And subsequently, in the process of processing the received single-photon-level light pulse at the receiving end, determining which light intensity of the single-photon-level light pulse accords with the light intensity in the pre-acquired light intensity marking information, and determining the light pulse which accords with the light intensity requirement based on the light intensity.
The polarization beam combiner 6 comprises two input ends and an output end, and the output end of the polarization beam combiner 6 can be connected with the input end of the rear optical fiber structure 7 through a waveguide.
The polarization beam combiner 6 is configured to combine two groups of input optical pulses with random light intensity and random phase according to a set polarization state to obtain a group of optical pulses with random light intensity and random polarization state, and input the group of optical pulses to the post-optical fiber structure 7.
The polarization state set in the polarization beam combiner 6 may be a horizontal polarization state or a vertical polarization state. That is, the polarization conduction mode of the optical pulse input to the polarization beam combiner 6 may be set to a TE mode (parallel to the waveguide section) or a TM mode (perpendicular to the waveguide section).
In one embodiment of the present invention, the polarization beam combiner 6 may be used to combine the TE mode polarized light pulses input from the two input ends simultaneously.
The method specifically comprises the following steps: assuming that the light energy of the optical pulse input at one input end of the polarization beam combiner 6 is T1, the polarization mode is TE mode, the light energy of the optical pulse input at the other input end of the polarization beam combiner 6 is T2, and the polarization mode is also TE mode, the optical field of the combined optical pulse is the superposition of the TE mode of the optical energy T1 and the TM mode of the optical energy T2.
The rear optical fiber structure 7 is used for performing attenuation processing and polarization state measurement on the input optical pulse according to the set single photon magnitude, and outputting the obtained single photon magnitude optical pulse and polarization state information to the receiving end.
The single photon magnitude specifically set by the rear optical fiber structure 7 is related to the communication protocol according to which the common communication protocol includes BB84 protocol, six-state protocol, and reference system independent protocol. According to different communication protocols, the single photon magnitude specifically set by the rear optical fiber structure 7 may be different.
It should be noted that, in the subsequent process of processing the received single-photon-level optical pulses at the receiving end, it is determined which light intensities of the single-photon-level optical pulses meet the light intensity in the pre-acquired light intensity marking information, and it is determined which polarization states of the single-photon-level optical pulses meet the polarization state required by the protocol based on the pre-acquired polarization state information, and the optical pulses meeting the light intensity requirement and the polarization state requirement are determined based on the determination.
In the embodiment of the invention, the optical interference structure is used for carrying out optical interference on optical pulses with random phases and the same light intensity input by the same group of pulse lasers to obtain two groups of optical pulses with random phases and random light intensities after interference, the optical pulses after interference of different groups are input to the polarization beam combiner, the high-speed photoelectric detector is used for detecting the light intensity of the optical pulses after interference and carrying out light intensity marking, the obtained light intensity marking information is output to a receiving end, the polarization beam combiner is used for combining the input optical pulses to obtain a group of optical pulses with random light intensities and random polarization states and inputting the group of optical pulses to the post-positioned optical fiber structure, the post-positioned optical fiber structure attenuates the input optical pulses with random light intensities and random polarization states into optical pulses with single photon magnitudes according to the set single photon magnitudes and sends the optical pulses to the receiving end, the polarization state measurement is carried out on the input optical pulses, and the obtained polarization state information is sent to the receiving end. The receiving end processes the received single photon magnitude optical pulse based on the light intensity mark information and the polarization state information to determine the optical pulse which meets the light intensity requirement and the polarization state requirement, so that the key can be coded on the optical quantum without modulating at the transmitting end, namely, the on-chip high-speed modulation is avoided; furthermore, at least the optical interference structure and the polarization beam combiner are arranged on the chip, so that the transmitting end does not need to be realized completely based on discrete optical components and a PCB (printed circuit board), the cost and the volume of the transmitting end are reduced, and the cost and the volume of the quantum key distribution system where the transmitting end is located are further reduced.
Based on the transmitting end provided in the above embodiment of the present invention, when the optical interference structure specifically includes the first 50: the device comprises a first pulse laser 1, a second pulse laser 2, a third pulse laser 3, a fourth pulse laser 4, a first 50.
The first 50.
Specifically, a first light inlet of the first 50.
The first 50.
It should be noted that, if two light input ports of the first 50.
The first high-speed photodetector 10 is configured to detect the light intensity of the input second light pulse, perform light intensity labeling, and output light intensity labeling information to the receiving end. I.e. to inform the receiving end of the light intensity of the light pulse that meets the protocol requirements.
Wherein the first light pulse and the second light pulse contain the same information.
A first light inlet of the second 50.
The second 50.
Wherein the third light pulse and the fourth light pulse contain the same information.
It should be noted that, if two light input ports of the second 50.
The second high-speed photodetector 11 is configured to detect light intensity of the input fourth light pulse, perform light intensity labeling, and output light intensity labeling information to the receiving end. I.e. to inform the receiving end of the light intensity of the light pulses that meet the protocol requirements.
The output end of the polarization beam combiner 6 is connected with the input end of the post-positioned optical fiber structure 7, and is used for combining the input optical pulses according to the set polarization state, and inputting the obtained optical pulses with random light intensity and random polarization state to the post-positioned optical fiber structure 7.
The post-positioned optical fiber structure 7 is used for performing attenuation processing and polarization state measurement on the input optical pulse according to the set single-photon magnitude, and outputting the obtained optical pulse with the single-photon magnitude and polarization state information to a receiving end.
In the embodiment of the present invention, the light pulses input by the pulse laser are combined and split by a first 50 optical beam splitter and a second 50 optical beam splitter respectively, so as to obtain a first light pulse and a second light pulse split by the first 50; and measuring the polarization state of the input optical pulse, and sending the obtained polarization state information to a receiving end. The receiving end processes the received single photon magnitude optical pulse based on the light intensity mark information and the polarization state information to determine the optical pulse which meets the light intensity requirement and the polarization state requirement, so that the key can be coded on the optical quantum without modulating at the transmitting end, namely, the on-chip high-speed modulation is avoided; meanwhile, at least the first 50.
Based on the transmitting end provided in the foregoing embodiment of the present invention, when the rear optical fiber structure includes the optical splitter, the polarization analysis module, and the optical attenuation module, as shown in fig. 3, a schematic structural diagram of the transmitting end for quantum key distribution provided in the embodiment of the present invention is shown, where the transmitting end includes: the light attenuation module comprises a first pulse laser 1, a second pulse laser 2, a third pulse laser 3, a fourth pulse laser 4, a first 50 optical beam splitter 8, a second 50 optical beam splitter 9, a first high-speed photodetector 10, a second high-speed photodetector 11, a polarization beam combiner 6, an optical beam splitter 12, a polarization analysis module 13 and a light attenuation module 14.
The first 50.
In one embodiment of the present invention, one or more of the optical beam splitter 12, the polarization analysis module 13, and the optical attenuation module 14 are also disposed on the chip.
Specifically, the light inlet of the optical splitter 12 is connected to the output end of the polarization beam combiner 6, the lower end of the output end of the optical splitter 12 is connected to the input end of the polarization analysis module 13, and the upper end of the output end of the optical splitter 12 is connected to the input end of the optical attenuation module 14.
The optical splitter 12 can split the light energy, and specifically, the optical splitter 12 can split the light pulses input via the polarization beam combiner 6 according to a specific light energy ratio, input one group of the split light pulses to the polarization analysis module 13, and input the other group of the split light pulses to the light attenuation module 14.
In one embodiment of the present invention, the beam splitter 12 can be selected from a 90. Specifically, a Direct Coupler (DC) and a multi-mode interferometer (MMI) are mainly included according to the chip material.
When the optical beam splitter 12 selects the 90.
When the optical splitter 12 selects the 99.
When the beam splitter 12 selects the third 50.
The polarization analysis module 13 may be a polarization analyzer, and is configured to measure a polarization state of the input optical pulse and output the obtained polarization state information to the receiving end, that is, notify the receiving end of the optical pulse whose polarization state meets the protocol requirement.
For example, the polarization state required by the protocol is 0 degree, 90 degrees, 180 degrees, and 270 degrees, the polarization analysis module 13 measures the polarization state of a group of input divided optical pulses, marks the optical pulses with the polarization states of 0 degree, 90 degrees, 180 degrees, and/or 270 degrees, obtains polarization state information, and informs the receiving end of the polarization state information, so that the receiving end processes the received single-photon-level optical pulses based on the polarization state information, determines the optical pulses meeting the polarization state requirement, and performs subsequent decoding.
The light attenuation module 14 is configured to perform attenuation processing on the input light pulse according to a set single photon magnitude to obtain a single photon magnitude light pulse, and output the single photon magnitude light pulse to the receiving end.
It should be noted that in this embodiment, the connection modes and the execution processes of the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, the fourth pulse laser 4, the first 50 optical beam splitter 8, the second 50 optical beam splitter 9, the first high-speed photodetector 10, and the second high-speed photodetector 11 are the same as those of the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, the fourth pulse laser 4, the first 50 optical beam splitter 8, and the second 50 optical beam splitter 9, the first high-speed photodetector 10, and the second high-speed photodetector 11 shown in fig. 2, and reference is not repeated here for details.
In the embodiment of the invention, the optical beam splitter, the polarization analysis module and the optical attenuation module are specifically arranged in the rear optical fiber structure, so that the polarization analysis module measures the polarization state of the optical pulse input by the optical beam splitter and informs the obtained polarization state information to the receiving end, and the optical attenuation module attenuates the optical pulse input by the optical beam splitter to obtain the optical pulse with single photon magnitude and outputs the optical pulse to the receiving end.
Based on the transmitting end provided by the above embodiment of the present invention, when the optical splitter adopts a 90: the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, the fourth pulse laser 4, the first 50 optical beam splitter 8, the second 50 optical beam splitter 9, the first high-speed photodetector 10, the second high-speed photodetector 11, the polarization beam combiner 6, 90.
The first 50.
In the embodiment of the invention, the light pulse entering the 90.
Based on the transmitting terminal provided by the above embodiment of the present invention, when the 90: the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, the fourth pulse laser 4, the first 50 optical beam splitter 8, the second 50 optical beam splitter 9, the first high-speed photodetector 10, the second high-speed photodetector 11, the polarization beam combiner 6, 90.
The first 50.
In the embodiment of the present invention, the first 50.
In order to make the present application clearer, the operation principle of the transmitting end will be described in detail by specific examples.
Fig. 6 is a schematic structural diagram of a transmitting end for quantum key distribution according to an embodiment of the present invention. Since the pulses generated by the pulsed lasers are emitted continuously, one pulse generated by each pulsed laser is illustrated here.
As shown in fig. 6, the first pulse laser 1 generates pulse 1, and the second pulse laser generates pulse 2, which are input to the first 50. At the same time, the third pulse laser 3 and the fourth pulse laser 4 also generate one optical pulse respectively and input to the second 50.
Since the implementation process of the first pulse laser 1 and the second pulse laser 2 in the first 50 optical beam splitter 8 is the same as the implementation process of the third pulse laser 3 and the fourth pulse laser 4 in the second 50 optical beam splitter 9, the following description will be made by taking the implementation process of the first pulse laser 1 and the second pulse laser 2 in the first 50 optical beam splitter 8 as an example.
Since the phase difference between pulse 1 and pulse 2 is random, an interference phenomenon occurs when the two light pulses meet at the first 50.
At this time, the intensities of the light pulses emitted from the upper end and the lower end of the output end of the first 50:
and is provided withI 1 +I 2 =I up +I down WhereinI 1 、I 2 、I up 、I down And an
The light energy of the upper end and the lower end of the output end of the pulse 1 and the pulse 2 respectively corresponds to the phase difference between the pulse 1 and the pulse 2.
As can be seen from the formula for calculating the intensity of the light pulses emitted from the upper end and the lower end of the output end of the first 50I down Is randomly varied, but the intensity of the light pulse output at the upper end of the output end of the first 50I up Thereby, the intensity of the light pulse output from the lower end of the output end of the first 50I down 。
Specifically, the first high-speed photodetector 10 is configured to detect light intensity of the light pulse emitted from the upper end of the output end of the first 50.
It should be noted that the phases of the light pulses emitted from the lower end of the output end of the first 50.
Because the polarization beam combiner 6 (including the two-dimensional grating) disposed on the chip is used to combine the two light pulses at the input end according to the polarization states thereof, in this embodiment, the polarization states at the upper and lower ends of the input end are both TE modes (i.e., horizontal polarization states), and the polarization state of the light pulse combined by the polarization beam combiner 6 can be determined by the polar angle and the azimuth angle thereof on the poincare sphere, respectively:
the light intensity of the light pulse output after being combined by the polarization beam combiner 6 isI out =I 3 +I 4 Therefore, it can be seen that the polarization state and the light intensity of the light pulse output by the polarization beam combiner 6 are randomly changed, and a part of the light pulse can be split to the polarization analysis module 13 by the subsequent 90. The polarization analysis module 13 detects the light pulse whose polarization state meets the protocol requirement, obtains the polarization state information and outputs the polarization state information to the receiving end.
So in summary: the work flow of the transmitting end in fig. 6 is as follows:
1. four independent gain switch pulse lasers (a first pulse laser 1, a second pulse laser 2, a third pulse laser 3 and a fourth pulse laser 4) generate 4 optical pulses with random phases and same intensity, and the optical pulses enter a 50% optical beam splitter in pairs; that is, the light pulses generated by the first pulse laser 1 and the second pulse laser 2 enter the first 50.
2. After the light pulses input by the first pulse laser 1 and the second pulse laser 2 are combined by the first 50.
That is, the light intensity of the pulse 3 can be deduced by detecting the light intensity of the first high-speed photodetector 10 connected to the first 50; the intensity of pulse 4 can be inferred by detecting it by a second high-speed photodetector 11 connected to a second 50. And the detected light intensity of the pulse 3 and the detected light intensity of the pulse 4 are subjected to light intensity marking, and the obtained light intensity marking information is output to a receiving end. After passing through the polarization beam combiner 6, as can be seen from the above description, the light intensity of the light pulse output by the polarization beam combiner 6 is random, and the polarization state is also random, the polarization state of the light pulse output by the polarization beam combiner 6 can be measured by the polarization analysis module 13, and the polarization analysis module 13 outputs the measured polarization state information to the receiving end.
3. The light pulse output by the polarization beam combiner 6 passes through an optical attenuator module 14, is attenuated into the light pulse with single photon magnitude required by the protocol, and is output to a receiving end.
After the above working states, it can be seen that the transmitting end can output random light energy and light pulses in random polarization states, the light energy range is 0 to 2I, and any polarization state can be output, so that the polarization states that can be output certainly include all polarization states such as horizontal polarization state, vertical polarization state, +45 degree polarization state, -45 degree polarization state, left-handed circular polarization state, right-handed circular polarization state, and the like required by polarization encoding. Where I is the light intensity of the light pulse generated by the pulsed laser, typically 1mW.
Therefore, at this time, the required light intensity and polarization state are selected according to the operating protocol requirement, and the random combination state of various specific intensities and polarizations required by polarization encoding can be completed by discarding the non-conforming ones in the communication process, namely, the selection after the state generation. In order to improve the operating efficiency of the transmitting end and to reduce the probability of discarding the light pulses, in actual operation a certain range of states is selected for both the polarization state and the photon number, specifically for the original photon numberμ 2 Actually correspond toPhoton number up toμ 2 ±△μI.e. for a particular polarization stateθAnd
angle, selection in the actual transmitting end corresponds toθ±△θAnd
namely, here△μ、△θAnd
the selection is made according to the actual transmitting end situation.
Based on the transmitting terminal provided by the embodiment of the invention, when the polarization analysis module and the light attenuation module are arranged on the chip. Fig. 7 shows a transmitting end for quantum key distribution according to an embodiment of the present invention, where the transmitting end includes: the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, the fourth pulse laser 4, the first 50 optical beam splitter 8, the second 50 optical beam splitter 9, the first high-speed photodetector 10, the second high-speed photodetector 11, the polarization beam combiner 6, 90.
The first 50.
In the embodiment of the present invention, by disposing the first 50.
Based on the transmitting end provided in the foregoing embodiment of the present invention, when the first pulse laser, the second pulse laser, the third pulse laser, and the fourth pulse laser are disposed on the chip, as shown in fig. 8, the transmitting end for quantum key distribution provided in the embodiment of the present invention includes: the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, the fourth pulse laser 4, the first 50 optical beam splitter 8, the second 50 optical beam splitter 9, the first high-speed photodetector 10, the second high-speed photodetector 11, the polarization beam combiner 6, the polarization beam combiner 10, the second high-speed photodetector 11, the polarization analysis module 13, and the optical attenuation module 14 are all provided on one chip. I.e. a fully integrated transmitter. The chip may be an optical chip of InP material.
In the embodiment of the invention, the transmitting end is integrated on a whole chip, so that the transmitting end is not required to be realized based on a discrete optical component and a PCB (printed Circuit Board), the cost and the volume of the transmitting end are reduced, and the cost and the volume of a quantum key distribution system where the transmitting end is located are further reduced.
Based on the transmitting end provided by the above embodiments of the present invention, in a specific waveguide material, such as an SOI waveguide material, the polarization beam combiner may also be replaced by a two-dimensional grating structure. Fig. 9 is a diagram of the transmitting end obtained based on fig. 4, in which the polarization beam combiner is replaced by a two-dimensional grating, and specifically includes: the first pulse laser 1, the second pulse laser 2, the third pulse laser 3, the fourth pulse laser 4, the first 50 optical beam splitter 8, the second 50 optical beam splitter 9, the first high-speed photodetector 10, the second high-speed photodetector 11, the two-dimensional gratings 16, 90.
Wherein, the first 50.
Wherein the first incident end of the two-dimensional grating 16 is connected to the upper end of the output end of the group of output ends of the optical interference structure, in the present embodiment, as shown in fig. 9, the first incident end of the two-dimensional grating 16 is connected to one output end of the first 50.
The second incident end of the two-dimensional grating 16 is connected to the lower end of the output end of the other group of output ends of the optical interference structure, and in the present embodiment, as shown in fig. 9, the second incident end of the two-dimensional grating 16 is connected to one output end of the second 50.
The exit end of the two-dimensional grating 16 is connected to the input end of the rear optical fiber structure, and in this embodiment, as shown in fig. 9, the exit end of the two-dimensional grating 16 is connected to the light inlet of the 90.
The two-dimensional grating 16 is configured to combine the input optical pulses according to a set polarization state, input the obtained optical pulses to the rear optical fiber structure, and screen the optical pulses whose polarization states meet the protocol requirements from the rear optical fiber structure and output the optical pulses to the receiving end.
In the present embodiment, as shown in fig. 9, the optical pulse obtained after the two-dimensional grating 16 is combined is input to the optical splitter 15 of 90.
The two-dimensional grating 16 on the chip has the same function as the polarization beam combiner, that is, after one of the TE mode optical pulses input from the first incident end and the second incident end of the two-dimensional grating 16 is inverted into the TM mode, the optical pulse is superimposed with the other TE mode optical pulse, and the two TE mode optical pulses are input into the external coupling optical fiber. Such as input to the 90.
In the embodiment of the invention, the first 50 optical beam splitter, the second 50 optical beam splitter, the first high-speed photodetector, the second high-speed photodetector and the two-dimensional grating are arranged on one chip, so that the transmitting terminal is not required to be realized completely based on discrete optical components and a PCB (printed Circuit Board), thereby reducing the cost and the volume of the transmitting terminal and further reducing the cost and the volume of a quantum key distribution system where the transmitting terminal is located.
Based on the transmitting end provided in the above embodiment of the present invention, when the first 50. The transmitting end includes: the optical attenuator comprises a first pulse laser 1, a second pulse laser 2, a third pulse laser 3, a fourth pulse laser 4, an equal arm MZI interferometer 17, a first high-speed photodetector 10, a second high-speed photodetector 11, two-dimensional gratings 16, 90.
Wherein, the equal-arm MZI interferometer 17, the first high-speed photodetector 10, the second high-speed photodetector 11, and the two-dimensional grating 16 are disposed on a chip.
In the embodiment of the invention, the equal-arm MZI interferometer 17, the first high-speed photoelectric detector 10, the second high-speed photoelectric detector 11 and the two-dimensional grating 16 are arranged on one chip, so that the transmitting end is not required to be realized completely based on discrete optical components and a PCB (printed Circuit Board), the cost and the volume of the transmitting end are reduced, and the cost and the volume of a quantum key distribution system where the transmitting end is located are further reduced.
As can be seen from the transmitting terminals shown in fig. 1 to fig. 10, the transmitting terminal according to the embodiment of the present invention can meet the working requirements of various polarization encoded quantum key distribution protocols on the state modulation of the transmitting terminal by using a simple and easily implemented on-chip device structure, and meanwhile, under the technical conditions of the existing optical integrated chip, the manufacturing and mass production are easy, and the cost of the transmitting terminal is reduced.
Based on all the transmitting terminals provided by the embodiment of the present invention, the embodiment of the present invention further provides a quantum key distribution method correspondingly, and fig. 11 is a flowchart of the quantum key distribution method provided by the embodiment of the present invention.
The quantum key distribution method comprises the following steps:
s11: the pulse laser generates a light pulse and inputs the light pulse to the optical interference structure.
S12: the optical interference structure performs optical interference on input optical pulses based on the same group of input ends to obtain two groups of interfered optical pulses, inputs the different groups of interfered optical pulses to the polarization beam combiner, detects the light intensity of the two groups of interfered optical pulses by using the high-speed photoelectric detector, marks the light intensity, and outputs the obtained light intensity mark information to the receiving end.
In S12, the same information is included in the optical pulses after the interference of the same group.
S13: the polarization beam combiner combines the input optical pulses according to a set polarization state, and inputs the obtained optical pulses to the rear optical fiber structure.
S14: the rear optical fiber structure performs attenuation processing and polarization state measurement on the input optical pulse according to the set single photon magnitude, and outputs the obtained single photon magnitude optical pulse and polarization state information to the receiving end.
In the embodiment of the invention, the optical interference structure is used for carrying out optical interference on optical pulses with random phases and the same light intensity input by the same group of pulse lasers to obtain two groups of optical pulses with random phases and random light intensities after interference, the optical pulses after interference of different groups are input to the polarization beam combiner, the high-speed photoelectric detector is used for detecting the light intensity of the optical pulses after interference and carrying out light intensity marking, the obtained light intensity marking information is output to the receiving end, the polarization beam combiner is used for combining the input optical pulses to input the obtained optical pulses to the post-positioned optical fiber structure, the post-positioned optical fiber structure attenuates the input optical pulses into the optical pulses with single photon magnitude according to the set single photon magnitude and sends the optical pulses to the receiving end, the polarization state measurement is carried out on the input optical pulses, and the obtained polarization state information is sent to the receiving end. The receiving end processes the received single photon magnitude optical pulse based on the light intensity mark information and the polarization state information to determine the optical pulse meeting the light intensity requirement and the polarization state requirement, so that the key can be coded on the optical quantum without modulating at the transmitting end, namely, the on-chip high-speed modulation is avoided.
Based on the quantum key distribution method provided by the above embodiment of the present invention, further, when the optical interference structure specifically includes: as shown in fig. 12, when the first 50:
s21: the pulse laser generates a light pulse and inputs the light pulse to the optical interference structure.
S22: the first 50.
In S22, the first light pulse and the second light pulse contain the same information.
S23: and the first high-speed photoelectric detector detects the light intensity of the input second light pulse, marks the light intensity and outputs the obtained light intensity marking information to the receiving end.
S24: the second 50.
In S24, the third light pulse and the fourth light pulse contain the same information.
S25: and the second high-speed photoelectric detector detects the light intensity of the input fourth light pulse, marks the light intensity and outputs the obtained light intensity marking information to the receiving end.
S26: the polarization beam combiner combines the input optical pulses according to a set polarization state, and inputs the obtained optical pulses to the rear-mounted optical fiber structure.
S27: the rear optical fiber structure performs attenuation processing and polarization state measurement on the input optical pulse according to the set single photon magnitude, and outputs the obtained single photon magnitude optical pulse and polarization state information to the receiving end.
In the embodiment of the present invention, the light pulses input by the pulse laser are combined and split by a first 50 optical beam splitter and a second 50 optical beam splitter respectively, so as to obtain a first light pulse and a second light pulse split by the first 50; and measuring the polarization state of the input optical pulse, and sending the obtained polarization state information to a receiving end. Therefore, the receiving end can encode the key on the light quantum without modulating the transmitting end, namely, on-chip high-speed modulation is avoided.
Based on all the transmitting terminals provided in the above embodiments of the present invention, the embodiments of the present invention further provide a quantum key distribution system, as shown in fig. 13, the quantum key distribution system includes a transmitting terminal 131 and a receiving terminal 132.
The transmitting end 131 and the receiving end 132 may be connected by a waveguide, and the transmitting end 131 is configured to output the detected light intensity marking information, the measured polarization state information, and the generated single-photon-level light pulse to the receiving end 132.
The receiving end 132 is configured to receive the light intensity labeling information, the polarization state information, and the single photon magnitude optical pulse, and decode and measure the single photon magnitude optical pulse based on the light intensity labeling information and the polarization state information.
Among them, the transmitting terminal 131 shown in fig. 13 is one of the structures. The transmitting end 131 may also be any transmitting end for quantum key distribution provided in the above embodiments of the present invention.
The receiving end 132 may be any receiving end that is conventional and that is compatible with the transmitting end provided by the present invention.
In an embodiment of the present invention, the receiving end 132 includes a 50.
The transmitting end 131 performs optical interference and optical intensity detection and polarization state detection on an input optical pulse, outputs detected optical intensity mark information and measured polarization state information to the receiving end 132, the transmitting end 131 processes the optical pulse after the optical interference again, generates a single-photon-level optical pulse, transmits the single-photon-level optical pulse through a waveguide, and then enters a 50. After the corresponding single photon detector sends out a detection response, the detection result is recorded, and then the key distribution work can be completed through the base pair and error code estimation of the transmitting end 131 and the corresponding post-processing process.
In the embodiment of the invention, the light intensity marking information obtained by detection and the polarization state information obtained by measurement are output to the receiving end through the transmitting end, and the generated single photon magnitude optical pulse is output to the receiving end, so that the receiving end can decode the received single photon magnitude optical pulse based on the light intensity marking information and the polarization state information, and the key can be rapidly encoded on the light quantum without being modulated at the transmitting end, namely the receiving and the transmitting of the quantum key distribution system without on-chip high-speed modulation are completed; furthermore, as part or all of the devices of the transmitting end are arranged on a chip, the cost and the volume of the quantum key distribution system are greatly reduced.
It should be noted that in the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only used for convenience of description and simplification of the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present application. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in an article or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A transmitting end for quantum key distribution, the transmitting end comprising: the device comprises a pulse laser, an optical interference structure, a polarization beam combiner and a rear optical fiber structure;
the optical interference structure and the polarization beam combiner are arranged on a chip;
the pulse laser is used for generating optical pulses;
the optical interference structure consists of a 50;
the four input ends of the optical interference structure are respectively connected with different pulse lasers, two output ends of different groups are respectively connected with one input end of the polarization beam combiner, the other two output ends of the optical interference structure are respectively connected with the high-speed photoelectric detector, the optical interference structure is used for respectively carrying out optical interference on the optical pulses input based on the input ends of the same group to obtain two groups of interfered optical pulses, the different groups of interfered optical pulses are input into the polarization beam combiner, the high-speed photoelectric detectors are used for detecting the light intensity of the two groups of interfered optical pulses and carrying out light intensity marking, and the obtained light intensity marking information is output to a receiving end, wherein the information contained in the same group of interfered optical pulses is the same;
the output end of the polarization beam combiner is connected with the input end of the rear optical fiber structure, and the polarization beam combiner is used for combining the input optical pulses according to a set polarization state and inputting the obtained optical pulses to the rear optical fiber structure;
the post-positioned optical fiber structure is used for carrying out attenuation processing and polarization state measurement on the input optical pulse according to the set single-photon magnitude, and outputting the obtained optical pulse with the single-photon magnitude and polarization state information to the receiving end.
2. The transmitting end of claim 1, wherein the 50.
3. The transmitting end according to claim 1, characterized in that the optical interference structure comprises in particular: a first 50;
a first light inlet of the first 50;
the first 50;
the first high-speed photoelectric detector is used for detecting the light intensity of the input second light pulse, marking the light intensity and outputting light intensity marking information to the receiving end;
a first light inlet of the second 50;
the second 50;
the second high-speed photoelectric detector is used for detecting the light intensity of the input fourth light pulse, marking the light intensity and outputting the obtained light intensity marking information to the receiving end.
4. The launch end of any of claims 1 to 3 wherein the rear-facing fiber optic structure comprises:
the device comprises an optical beam splitter, a polarization analysis module and an optical attenuation module;
the light beam splitter is used for splitting light pulses input by the polarization beam combiner according to a specific light energy proportion, inputting one group of split light pulses into the polarization analysis module and inputting the other group of split light pulses into the light attenuation module;
the polarization analysis module is used for measuring the polarization state of the input light pulse and outputting the obtained polarization state information to the receiving end;
the light attenuation module is used for carrying out attenuation processing on the input light pulse according to the set single-photon magnitude to obtain the light pulse of the single-photon magnitude.
5. The transmitting end of claim 4, wherein the optical splitter comprises a 90.
6. The transmitting end according to claim 4, wherein any one or more of the pulsed laser, the optical beam splitter, the polarization analysis module and the optical attenuation module are disposed on the chip.
7. The transmitting end according to claim 1 or 2, wherein the polarization beam combiner comprises a two-dimensional grating;
the first incident end of the two-dimensional grating is connected with the upper end of the output end of one group of output ends of the optical interference structure, the second incident end of the two-dimensional grating is connected with the lower end of the output end of the other group of output ends of the optical interference structure, the emergent end of the two-dimensional grating is connected with the input end of the rear optical fiber structure, and the two-dimensional grating is used for combining input optical pulses according to a set polarization state and inputting the obtained optical pulses to the rear optical fiber structure.
8. A quantum key distribution method applied to the transmitting end of any one of claims 1 to 7, the transmitting end comprising: the optical fiber laser comprises a pulse laser, an optical interference structure, a polarization beam combiner and a rear optical fiber structure, wherein the method comprises the following steps:
the pulse laser generates light pulse and inputs the light pulse to the light interference structure;
the optical interference structure performs optical interference on input optical pulses based on the same group of input ends to obtain two groups of interfered optical pulses, inputs the different groups of interfered optical pulses to the polarization beam combiner, detects the light intensity of the two groups of interfered optical pulses by using the high-speed photoelectric detector, marks the light intensity, and outputs the obtained light intensity mark information to the receiving end, wherein the information contained in the same group of interfered optical pulses is the same;
the polarization beam combiner combines the input optical pulses according to a set polarization state, and inputs the obtained optical pulses to the rear optical fiber structure;
the rear optical fiber structure performs attenuation processing and polarization state measurement on the input optical pulse according to the set single photon magnitude, and outputs the obtained single photon magnitude optical pulse and polarization state information to the receiving end.
9. The quantum key distribution method of claim 8, wherein when the optical interference structure specifically comprises: when the first 50:
a first 50;
the first high-speed photoelectric detector detects the light intensity of the input second light pulse, marks the light intensity and outputs the obtained light intensity marking information to the receiving end;
the second 50;
and the second high-speed photoelectric detector detects the light intensity of the input fourth light pulse, marks the light intensity and outputs the obtained light intensity marking information to the receiving end.
10. A quantum key distribution system, comprising:
the transmitting end and the receiving end of any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310081884.7A CN115801255B (en) | 2023-02-08 | 2023-02-08 | Quantum key distribution method, transmitting terminal and quantum key distribution system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310081884.7A CN115801255B (en) | 2023-02-08 | 2023-02-08 | Quantum key distribution method, transmitting terminal and quantum key distribution system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115801255A true CN115801255A (en) | 2023-03-14 |
| CN115801255B CN115801255B (en) | 2023-04-07 |
Family
ID=85430507
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310081884.7A Active CN115801255B (en) | 2023-02-08 | 2023-02-08 | Quantum key distribution method, transmitting terminal and quantum key distribution system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115801255B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115189764A (en) * | 2022-07-14 | 2022-10-14 | 贵州航天天马机电科技有限公司 | Communication distance calculation method of laser wireless communication system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107612686A (en) * | 2017-09-07 | 2018-01-19 | 中南大学 | One-dimensional modulation continuous variable quantum key distribution system and its implementation based on heterodyne detection |
| CN110149208A (en) * | 2019-07-02 | 2019-08-20 | 安徽问天量子科技股份有限公司 | Integrated time phase quantum key dispatching system transmitting terminal coding module |
| CN110620652A (en) * | 2018-07-19 | 2019-12-27 | 科大国盾量子技术股份有限公司 | Quantum key distribution system and communication method thereof |
| WO2020140851A1 (en) * | 2018-12-30 | 2020-07-09 | 华南师范大学 | Quantum communication and quantum time-frequency transmission fusion network system and method |
| CN211509058U (en) * | 2020-04-01 | 2020-09-15 | 杭州顾宸科技有限公司 | Efficient phase encoding quantum key distribution system |
| CN114978348A (en) * | 2022-01-19 | 2022-08-30 | 合肥硅臻芯片技术有限公司 | Time phase quantum key distribution system and transmitting terminal structure thereof |
-
2023
- 2023-02-08 CN CN202310081884.7A patent/CN115801255B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107612686A (en) * | 2017-09-07 | 2018-01-19 | 中南大学 | One-dimensional modulation continuous variable quantum key distribution system and its implementation based on heterodyne detection |
| CN110620652A (en) * | 2018-07-19 | 2019-12-27 | 科大国盾量子技术股份有限公司 | Quantum key distribution system and communication method thereof |
| WO2020140851A1 (en) * | 2018-12-30 | 2020-07-09 | 华南师范大学 | Quantum communication and quantum time-frequency transmission fusion network system and method |
| CN110149208A (en) * | 2019-07-02 | 2019-08-20 | 安徽问天量子科技股份有限公司 | Integrated time phase quantum key dispatching system transmitting terminal coding module |
| CN211509058U (en) * | 2020-04-01 | 2020-09-15 | 杭州顾宸科技有限公司 | Efficient phase encoding quantum key distribution system |
| CN114978348A (en) * | 2022-01-19 | 2022-08-30 | 合肥硅臻芯片技术有限公司 | Time phase quantum key distribution system and transmitting terminal structure thereof |
Non-Patent Citations (1)
| Title |
|---|
| 马海强;赵建领;吴令安;: "一种相位编码、偏振检测的量子密钥分发系统" * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115189764A (en) * | 2022-07-14 | 2022-10-14 | 贵州航天天马机电科技有限公司 | Communication distance calculation method of laser wireless communication system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115801255B (en) | 2023-04-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6729852B2 (en) | Encoding device, and quantum key distribution device and system based on the same | |
| EP2248284B1 (en) | Optical transmitters and receivers for quantum key distribution | |
| US20100002881A1 (en) | Polarization-insensitive one-way quantum key distribution receiver, transmitter/receiver system | |
| WO2020043096A1 (en) | Coherent detection implementation apparatus, system, and method | |
| JP2018515046A (en) | Chip-based quantum key distribution | |
| EP2885886A2 (en) | Quantum communications system with integrated photonic devices | |
| CN115801255B (en) | Quantum key distribution method, transmitting terminal and quantum key distribution system | |
| JPH07327010A (en) | Space optical transmitter and space optical transmission method | |
| CN111555878A (en) | Integrated measuring equipment independent quantum key distribution system | |
| WO2021188045A1 (en) | System and apparatuses for measurement-device-independent quantum key distribution | |
| JP7214773B2 (en) | Optical modules, systems, transmitting units, receiving units, and quantum communication systems | |
| Du et al. | Silicon-based decoder for polarization-encoding quantum key distribution | |
| US20160337045A1 (en) | Reception and generation of light | |
| CN107370541A (en) | Frequency-tunable is without local oscillator phase-coded signal optics generation device and method | |
| CN115801254B (en) | Quantum key distribution method, transmitting terminal and quantum key distribution system | |
| CN209517162U (en) | A kind of palarization multiplexing two-way quantum key dissemination system | |
| Zhang et al. | Polarization-based quantum key distribution encoder and decoder on silicon photonics | |
| Soma et al. | Ultra-broadband surface-normal coherent optical receiver with nanometallic polarizers | |
| Zhong et al. | Precise ranging for the multi-region by using multi-beam chaotic polarization components in the multiple parallel optically pumped spin-VCSELs with optical injection | |
| CN110149208B (en) | Transmitting end coding module of integrated time phase coding quantum key distribution system | |
| CN211509059U (en) | Duplex polarization encoding quantum key distribution link | |
| CN111756526B (en) | Quantum key distribution system, transmitting end, receiving end and communication method thereof | |
| CN113992323B (en) | Chip-based measuring equipment independent quantum key distribution system and method | |
| US20220085895A1 (en) | Generation of optical pulses with controlled distributions of quadrature values | |
| CN112822012A (en) | Quantum key distribution equipment and quantum key distribution method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |