CN112994881B - Transmitting end, receiving end and system for quantum communication - Google Patents
Transmitting end, receiving end and system for quantum communication Download PDFInfo
- Publication number
- CN112994881B CN112994881B CN202110415919.7A CN202110415919A CN112994881B CN 112994881 B CN112994881 B CN 112994881B CN 202110415919 A CN202110415919 A CN 202110415919A CN 112994881 B CN112994881 B CN 112994881B
- Authority
- CN
- China
- Prior art keywords
- light
- polarization state
- polarization
- quantum
- photon detector
- 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.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
- H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
- H04L9/0816—Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
- H04L9/0852—Quantum cryptography
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/501—Structural aspects
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/70—Photonic quantum communication
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0201—Add-and-drop multiplexing
- H04J14/0202—Arrangements therefor
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Theoretical Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Optical Communication System (AREA)
Abstract
The invention provides a transmitting terminal, a receiving terminal and a system for quantum communication, wherein the transmitting terminal comprises: the optical encoding unit is configured to prepare first polarized light and encode information to be transmitted by taking the polarization state of the first polarized light as a polarization reference so as to obtain quantum light comprising the information to be transmitted; a beacon light preparation unit configured to prepare second polarized light, wherein a polarization state of the second polarized light is the same as a polarization state of the first polarized light; a wavelength division multiplexer configured to combine the second polarized light as beacon light and quantum light; and the transmitting telescope is configured to transmit the combined quantum light and the beacon light to the receiving end through the free space. The transmitting end, the receiving end and the system for quantum communication provided by the invention can perform offset compensation on the polarization state of quantum light received through free space under the condition of not interrupting decoding.
Description
Technical Field
The invention relates to the technical field of quantum communication, in particular to a transmitting end, a receiving end and a system for quantum communication.
Background
In a Quantum Key Distribution (QKD) system based on free space, a polarization state of Quantum light may shift due to various interferences in a process of transmitting the Quantum light from a transmitting end to a receiving end via the free space, which may cause that the Quantum light transmitted by the transmitting end cannot be correctly decoded by the receiving end or a relatively high decoding error rate occurs at the receiving end.
In the related art, the above problem is generally solved by performing offset compensation on the H polarization state, the V polarization state, the P polarization state, and the N polarization state of the quantum light before decoding at the receiving end. However, this offset compensation method not only interrupts the decoding process of the system, resulting in a reduced code rate, but also consumes a lot of optical devices.
Disclosure of Invention
The invention aims to provide a transmitting end, a receiving end and a system for quantum communication.
According to an aspect of the present invention, there is provided a transmitting terminal for quantum communication, the transmitting terminal comprising: the optical encoding unit is configured to prepare first polarized light and encode information to be transmitted by taking the polarization state of the first polarized light as a polarization reference so as to obtain quantum light comprising the information to be transmitted; a beacon light preparation unit configured to prepare second polarized light, wherein a polarization state of the second polarized light is the same as a polarization state of the first polarized light; a wavelength division multiplexer configured to combine the second polarized light as beacon light and quantum light; and the transmitting telescope is configured to transmit the combined quantum light and the beacon light to the receiving end through the free space.
According to one embodiment of the invention, the encoding is based on the BB84 protocol.
According to one embodiment of the present invention, an optical encoding unit includes: a first light source configured to emit a first light beam; a first polarizer configured to change the first light beam into first polarized light; a polarization state preparation unit configured to convert information to be transmitted into a polarization pulse having a predetermined polarization state with a polarization state of the first polarized light as a polarization reference, wherein the predetermined polarization state is one of an H-polarization state, a V-polarization state, a P-polarization state, and an N-polarization state; and a decoy state preparation unit configured to perform decoy state processing on the polarized pulse to obtain quantum light.
According to one embodiment of the invention, the beacon light preparation unit comprises: a second light source configured to emit a second light beam; a second polarizer configured to change the second light beam into second polarized light.
According to an embodiment of the present invention, the transmitting end further includes: a random number generator configured to generate information to be transmitted.
According to one embodiment of the present invention, the polarization state of the first polarized light is one of an H-polarization state, a V-polarization state, a P-polarization state, and an N-polarization state.
According to another aspect of the present invention, there is provided a receiving end for quantum communication, the receiving end comprising: a receiving telescope configured to receive the light beam from the transmitting end via free space; a wavelength division multiplexer configured to split the quantum light and the beacon light from the received light beam; an optical decoding unit configured to decode information to be transmitted from the quantum light; a polarization detection unit configured to detect whether a polarization state of the beacon light is shifted; a polarization controller configured to adjust a polarization reference for the received light beam in response to the polarization state of the beacon light being shifted to compensate for the shift in the polarization state of the quantum light.
According to one embodiment of the invention, the polarization controller is disposed between the receiving telescope and the wavelength division multiplexer.
According to one embodiment of the present invention, the polarization state of the beacon light is shifted based on the incident light power of the beacon light not reaching a maximum.
According to one embodiment of the present invention, a polarization detection unit includes: an analyzer configured to split two orthogonal beams from the beacon light; and the photoelectric detector is configured to detect the incident light power of one of the two beams of light as the incident light power of the beacon light and feed back the detected incident light power of the beacon light to the polarization controller.
According to an embodiment of the present invention, the polarization controller is further configured to adjust the polarization reference for the received light beam in response to the detected incident light power of the beacon light not reaching a maximum, to change the incident light power of the beacon light by the adjusted polarization reference, and to realize the offset compensation of the polarization state of the quantum light when the incident light power of the beacon light reaches the maximum.
According to one embodiment of the invention, the decoding is based on the BB84 protocol.
According to one embodiment of the present invention, an optical decoding unit includes: a first single photon detector configured to detect a photon having an H polarization state in the quantum light; a second single photon detector configured to detect a photon having a V polarization state in the quantum light; a third single photon detector configured to detect a photon having a P polarization state in the quantum light; a fourth single photon detector configured to detect a photon having an N polarization state in the quantum light; a first polarization beam splitter configured to split photons of the quantum light having an H polarization state to a first single photon detector and split photons of the quantum light having a V polarization state to a second single photon detector; a second polarization beam splitter configured to split photons of the quantum light having a P polarization state to a third single photon detector and split photons of the quantum light having an N polarization state to a fourth single photon detector; a beam splitter configured to split photons having an H polarization state and photons having a V polarization state in the quantum light to the first polarization beam splitter, and to split photons having a P polarization state and photons having an N polarization state in the quantum light to the second polarization beam splitter.
According to one embodiment of the invention, the first single-photon detector, the second single-photon detector, the third single-photon detector, the fourth single-photon detector, the first polarization beam splitter, the second polarization beam splitter and the beam splitter are connected through polarization-maintaining optical fibers, and the polarization controller, the wavelength division multiplexer and the optical decoding unit are connected through polarization-maintaining optical fibers.
According to another aspect of the present invention, there is provided a system for quantum communication, comprising a transmitting end and a receiving end, wherein the transmitting end comprises: the optical encoding unit is configured to prepare first polarized light and encode information to be transmitted by taking the polarization state of the first polarized light as a polarization reference so as to obtain quantum light comprising the information to be transmitted; a beacon light preparation unit configured to prepare second polarized light, wherein a polarization state of the second polarized light is the same as a polarization state of the first polarized light; a first wavelength division multiplexer configured to combine the second polarized light as beacon light and quantum light; a transmitting telescope configured to transmit the combined quantum light and beacon light to a receiving end via a free space, the receiving end including: a receiving telescope configured to receive the light beam from the transmitting end via free space; a second wavelength division multiplexer configured to split the quantum light and the beacon light from the received light beam; an optical decoding unit configured to decode information to be transmitted from the quantum light; a polarization detection unit configured to detect whether a polarization state of the beacon light is shifted; a polarization controller configured to adjust a polarization reference for the received light beam in response to the polarization state of the beacon light being shifted to compensate for the shift in the polarization state of the quantum light.
According to one embodiment of the present invention, an optical encoding unit includes: a first light source configured to emit a first light beam; a first polarizer configured to change the first light beam into first polarized light; a polarization state preparation unit configured to convert information to be transmitted into a polarization pulse having a predetermined polarization state with a polarization state of the first polarized light as a polarization reference, wherein the predetermined polarization state is one of an H-polarization state, a V-polarization state, a P-polarization state, and an N-polarization state; and a decoy state preparation unit configured to perform decoy state processing on the polarized pulse to obtain quantum light.
According to one embodiment of the invention, the beacon light preparation unit comprises: a second light source configured to emit a second light beam; a second polarizer configured to change the second light beam into second polarized light.
According to an embodiment of the present invention, the transmitting end further includes: a random number generator configured to generate information to be transmitted.
According to one embodiment of the present invention, the polarization state of the first polarized light is one of an H-polarization state, a V-polarization state, a P-polarization state, and an N-polarization state.
According to one embodiment of the invention, the polarization controller is disposed between the receiving telescope and the wavelength division multiplexer.
According to one embodiment of the present invention, the polarization state of the beacon light is shifted based on the incident light power of the beacon light not reaching a maximum.
According to one embodiment of the present invention, a polarization detection unit includes: an analyzer configured to split two orthogonal beams from the beacon light; and the photoelectric detector is configured to detect the incident light power of one of the two beams of light as the incident light power of the beacon light and feed back the detected incident light power of the beacon light to the polarization controller.
According to an embodiment of the present invention, the polarization controller is further configured to adjust the polarization reference for the received light beam in response to the detected incident light power of the beacon light not reaching a maximum, to change the incident light power of the beacon light by the adjusted polarization reference, and to realize the offset compensation of the polarization state of the quantum light when the incident light power of the beacon light reaches the maximum.
According to one embodiment of the present invention, an optical decoding unit includes: a first single photon detector configured to detect a photon having an H polarization state in the quantum light; a second single photon detector configured to detect a photon having a V polarization state in the quantum light; a third single photon detector configured to detect a photon having a P polarization state in the quantum light; a fourth single photon detector configured to detect a photon having an N polarization state in the quantum light; a first polarization beam splitter configured to split photons of the quantum light having an H polarization state to a first single photon detector and split photons of the quantum light having a V polarization state to a second single photon detector; a second polarization beam splitter configured to split photons of the quantum light having a P polarization state to a third single photon detector and split photons of the quantum light having an N polarization state to a fourth single photon detector; a beam splitter configured to split photons having an H polarization state and photons having a V polarization state in the quantum light to the first polarization beam splitter, and to split photons having a P polarization state and photons having an N polarization state in the quantum light to the second polarization beam splitter.
According to one embodiment of the invention, the first single-photon detector, the second single-photon detector, the third single-photon detector, the fourth single-photon detector, the first polarization beam splitter, the second polarization beam splitter and the beam splitter are connected through polarization-maintaining optical fibers, and the polarization controller, the second wavelength division multiplexer and the optical decoding unit are connected through polarization-maintaining optical fibers.
According to one embodiment of the invention, the encoding and decoding is based on the BB84 protocol.
The transmitting end, the receiving end and the system for quantum communication according to the exemplary embodiments of the present invention can offset and compensate the polarization state of quantum light received via free space without interrupting decoding, which not only effectively ensures the continuity of system coding, but also further improves the accuracy of system decoding.
Drawings
The above objects and features of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings.
Fig. 1 shows a schematic diagram of a system for quantum communication according to an exemplary embodiment of the present invention.
Fig. 2 shows a schematic diagram of a device structure of a transmitting end for quantum communication according to an exemplary embodiment of the present invention.
Fig. 3 illustrates a schematic diagram of a device structure of a receiving end for quantum communication according to an exemplary embodiment of the present invention.
Detailed Description
The conception of the invention is as follows: in a system for quantum communication, such as, but not limited to, a QKD system, offset compensation is performed on the polarization state of quantum light received via free space at a receiving end by preparing beacon light whose polarization state is the same as a polarization reference of the quantum light (e.g., the polarization state of the polarization light used to prepare the quantum light or one of the H-polarization state, the V-polarization state, the P-polarization state, and the N-polarization state of the quantum light, etc.) at a transmitting end, so that the system for quantum communication can achieve offset compensation on the polarization state of the quantum light without interrupting decoding, thereby effectively ensuring continuity of system coding and improving accuracy of system decoding.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Fig. 1 shows a schematic diagram of a system 100 for quantum communication according to an exemplary embodiment of the present invention.
Referring to fig. 1, a system 100 for quantum communication may include a transmitting end 200 and a receiving end 300.
In the system 100 shown in fig. 1, the transmitting end 200 may include an optical encoding unit 210, a beacon light preparation unit 220, a wavelength division multiplexing unit 230, and a transmitting telescope240, wherein the optical encoding unit 210 may be configured to prepare a first polarized light and encode information to be transmitted with a polarization state of the first polarized light as a polarization reference to obtain quantum light λ including information to be transmitted1(ii) a The beacon light preparation unit 220 may be configured to prepare second polarized light, wherein the polarization state of the second polarized light is the same as the polarization state of the first polarized light; the wavelength division multiplexer 230 may be configured to use the second polarized light as the beacon light λ2And quantum light lambda1Combining; the transmitting telescope 240 can be configured to transmit the combined quantum light λ to a receiving end via free space1And beacon light lambda2。
In the system 100 shown in fig. 1, the receiving end 300 may include a receiving telescope 310, a wavelength division multiplexer 320, an optical decoding unit 330, a polarization detection unit 340, and a polarization controller 350, wherein the receiving telescope 310 may be configured to receive the light beam from the transmitting end 200 via free space; the wavelength division multiplexer 320 may be configured to split the quantum light λ from the received light beam1And beacon light lambda2(ii) a Optical decoding unit 330 may be configured to decode quantum light λ1Decoding information to be transmitted; the polarization detection unit 340 may be configured to detect the beacon light λ2Whether the polarization state of (a) is shifted; the polarization controller 350 may be configured to respond to the beacon light λ2To adjust a polarization reference for the received beam to adjust the quantum light lambda1Is offset compensated.
Thus, in the system 100 shown in fig. 1, the polarization controller 350 may be disposed between the receiving telescope 310 and the wavelength division multiplexer 320. This enables the receiving end 300 to indirectly implement the quantum light λ by performing offset compensation on the polarization state of the received light beam before splitting and decoding the received light beam1To compensate for the shift in polarization state. Thus, the system 100 shown in FIG. 1 is capable of real-time alignment of received quantum light λ without interrupting decoding1The polarization state of the optical fiber is offset compensated, so that the system code continuity is effectively ensured.
By way of example, of light of the first polarizationThe polarization state may be one of H polarization state, V polarization state, P polarization state and N polarization state, and may be other polarization angles (such as 20 degrees), for which the present invention is not limited. Accordingly, the polarization state of the second polarized light may be one of the H-polarization state, the V-polarization state, the P-polarization state and the N-polarization state, or other polarization angles (such as 20 degrees), and the invention is not limited thereto, as long as the polarization state of the second polarized light is consistent with the polarization state of the first polarized light, so that the beacon light λ may be made2Of the polarization state of the quantum light lambda1The polarization state shift of (a) is kept uniform.
In addition, in some examples, the information to be transmitted may be a key generated by a random number generator, or may be information output by other devices, and the present invention is not limited thereto as long as the information can be converted into 4 polarization states of light.
Thus, in the case where the information to be transmitted is a secret key generated by a random number generator, the transmitting end 200 in the system 100 shown in fig. 1 may further include a random number generator (not shown), which may be configured to generate the information to be transmitted.
Next, an implementation structure of the transmitting terminal 200 will be specifically described.
In one example, a single light source may be used to produce quantum light λ based on a polarization state of first polarized light via a sagnac interferometer and a phase modulator1Of 4 polarization states (i.e., H-polarization state, V-polarization state, P-polarization state, and N-polarization state), another light source is used to prepare the beacon light λ2. Thus, in this example, the emission end 200 can be implemented for quantum light λ using only 2 light sources1And beacon light lambda2And (4) preparing.
Fig. 2 shows a schematic diagram of an apparatus structure of a transmitting terminal 200 for quantum communication according to an exemplary embodiment of the present invention.
Referring to fig. 2, in the case where encoding is performed based on the BB84 protocol, in the transmitting end 200 shown in fig. 2, the optical encoding unit 210 may include a first light source 211, a first polarizer 212, a polarization state preparation unit 213, and a decoy schemeA unit 214, wherein the first light source 211 may be configured to emit a first light beam; the first polarizer 212 may be configured to change the first light beam into first polarized light; the polarization state preparation unit 213 may be configured to convert information to be transmitted into a polarized pulse having a predetermined polarization state with the polarization state of the first polarized light as a polarization reference, wherein the predetermined polarization state is one of an H-polarization state, a V-polarization state, a P-polarization state, and an N-polarization state; the decoy state preparation unit 214 may be configured to perform decoy state processing on the polarized pulse to obtain the quantum light λ1. The beacon light preparation unit 220 may comprise a second light source 221 and a second polarizer 222, wherein the second light source 221 may be configured to emit a second light beam; the second polarizer 222 may be configured to turn the second light beam into second polarized light.
It can be seen that the transmitting end 200 shown in fig. 2 not only enables the beacon light λ2Of the polarization state of the quantum light lambda1The polarization state shift of the light source is consistent, and the number of optical devices used by the transmitting end 200 can be effectively reduced.
It should be understood that, although fig. 2 shows a schematic diagram of a device structure of the transmitting terminal 200 for quantum communication according to an exemplary embodiment of the present invention, the present invention is not limited thereto, and other device structures may be employed to implement the transmitting terminal 200 for quantum communication according to an exemplary embodiment of the present invention. For example, in another example, 4 light sources may be used to separately produce quantum light λ1Using 1 light source to prepare the beacon light lambda2The polarization state of (c). Thus, in this example, the emitter 200 may be implemented using 5 light sources for quantum light λ1And beacon light lambda2And (4) preparing. However, more optics need to be consumed in this example than in the previous example.
Next, an implementation structure of the receiving end 300 will be specifically described.
The implementation structure of the receiving end 300 may depend on the quantum light λ received via free space1The offset compensation method is adopted. Due to beacon light lambda2Polarization state of and quantum light lambda1Have the same polarization reference due toThe quantum light λ1The polarization state of (a) is shifted after being launched to the receiving end 300 via free space and the beacon light lambda2Is the same after being launched to the receiving end 300 via free space. Thus, at the receiving end 300, it may be based on the beacon light λ2To determine the quantum light lambda1Of the polarization state of the light beam. Due to beacon light lambda2The polarization state of the beacon light can be shifted based on the beacon light lambda2Is determined based on the beacon light λ, in one example, because the incident light power of (b) is not maximized2To quantum light lambda1Is detected and compensated for.
Fig. 3 illustrates a schematic diagram of an apparatus structure of a receiving end 300 for quantum communication according to an exemplary embodiment of the present invention.
Referring to fig. 3, in the receiving end 300 shown in fig. 3, the polarization detection unit 340 may include an analyzer 341 and a photodetector 342, wherein the analyzer 341 may be configured to detect the beacon light λ from the beacon light2Two beams of light which are orthogonal are split; photodetector 342 may be configured to use the incident optical power of one of the two beams as beacon light λ2Detects the incident light power of the beacon light and detects the beacon light lambda2Is fed back to the polarization controller 350. Accordingly, the polarization controller 350 may be further configured to respond to the detected beacon light λ2To adjust the polarization reference for the received light beam to change the beacon light lambda by the adjusted polarization reference2And at the beacon light λ2When the incident light power reaches the maximum, the quantum light lambda is realized1To compensate for the shift in polarization state.
It should be understood that although described above based on beacon light λ2To quantum light lambda1Is detected and compensated for, but the present invention is not limited thereto, and may be based on the beacon light λ2For quantum light λ1Is detected and compensated for.
In the case where the decoding is performed based on the BB84 protocol, in the receiving end 300 shown in fig. 3, the optical decoding unit 330 may include a first single-photon detector 331, a second single-photon detector 332, a third single-photon detector 333, a fourth single-photon detector 334, a first polarization beam splitter 335, a second polarization beam splitter 336, and a beam splitter 337, wherein the first single-photon detector 331 may be configured to detect the quantum light λ1Photons having an H polarization state; the second single-photon detector 332 may be configured to detect quantum light λ1Photons having a V polarization state; the third single-photon detector 333 may be configured to detect quantum light λ1A photon having a P polarization state; the fourth single-photon detector 334 may be configured to detect quantum light λ1Photons having an N polarization state; first polarizing beam splitter 335 may be configured to split quantum light λ1The photons with the H polarization state in (b) are split to the first single photon detector 331 and quantum light λ is transmitted1The photons having the V polarization state in (1) are split to the second single-photon detector 332; second polarizing beam splitter 336 may be configured to split quantum light λ1The photons with P polarization state in (b) are split to the third single-photon detector 333 and quantum light λ is transmitted1The photons having the N polarization state in (1) are split to a fourth single photon detector 334; beam splitter 337 may be configured to split quantum light λ1The photons having the H polarization state and the photons having the V polarization state of (b) are split to the first polarization beam splitter 335 and quantum light λ is split1The photons having the P polarization state and the photons having the N polarization state in (1) are split to the second polarization beam splitter 336.
In addition, to prevent the compensated quantum light lambda1The polarization state of (b) is shifted inside the receiving end 300, and each optical device inside the receiving end 300 can be connected by using a polarization maintaining fiber, so that in the receiving end 300 shown in fig. 3, the first single-photon detector 331, the second single-photon detector 332, the third single-photon detector 333, the fourth single-photon detector 334, the first polarization beam splitter 335, the second polarization beam splitter 336, the beam splitter 337, the first single-photon detector 331, the second single-photon detector 332, the third single-photon detector 333, the fourth single-photon detector 333, and the likeThe sub-detectors 334, the first polarization beam splitter 335, the second polarization beam splitter 336 and the beam splitter 337, and the polarization controller 350, the wavelength division multiplexer 320 and the optical decoding unit 330 may be connected via polarization-maintaining fibers.
It should be understood that, although fig. 3 shows a schematic diagram of an apparatus structure of the receiving end 300 for quantum communication according to an exemplary embodiment of the present invention, the present invention is not limited thereto, and other apparatus structures may be employed to implement the receiving end 300 for quantum communication according to an exemplary embodiment of the present invention.
It can be seen that the transmitting end, the receiving end and the system for quantum communication according to the exemplary embodiments of the present invention can offset-compensate quantum light received via free space without interrupting decoding, which not only effectively ensures continuity of system coding, but also further improves accuracy of system decoding.
While the present application has been shown and described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made to these embodiments without departing from the spirit and scope of the present application as defined by the following claims.
Claims (20)
1. A transmitting end for quantum communication, comprising:
the optical encoding unit is configured to prepare first polarized light and encode information to be transmitted by taking the polarization state of the first polarized light as a polarization reference so as to obtain quantum light comprising the information to be transmitted;
a beacon light preparation unit configured to prepare second polarized light, wherein a polarization state of the second polarized light is the same as a polarization state of the first polarized light;
a wavelength division multiplexer configured to combine the second polarized light as beacon light and quantum light;
a transmitting telescope configured to transmit the combined quantum light and the beacon light to a receiving end via a free space such that the receiving end detects whether a polarization state of the quantum light is shifted based on whether an incident light power of one of two orthogonal beams split from the beacon light reaches a maximum, and adjusts a polarization reference for the combined quantum light and the beacon light received from the transmitting end in response to the detected incident light power not reaching the maximum to change the detected incident light power by the adjusted polarization reference and realize a shift compensation of the polarization state of the quantum light when the detected incident light power reaches the maximum.
2. The transmitting end of claim 1, wherein the encoding is based on the BB84 protocol.
3. The transmitting end according to claim 2, wherein the optical encoding unit comprises:
a first light source configured to emit a first light beam;
a first polarizer configured to change the first light beam into first polarized light;
a polarization state preparation unit configured to convert information to be transmitted into a polarization pulse having a predetermined polarization state with a polarization state of the first polarized light as a polarization reference, wherein the predetermined polarization state is one of an H-polarization state, a V-polarization state, a P-polarization state, and an N-polarization state;
and a decoy state preparation unit configured to perform decoy state processing on the polarized pulse to obtain quantum light.
4. The transmitting terminal according to claim 1, wherein the beacon light preparation unit comprises:
a second light source configured to emit a second light beam;
a second polarizer configured to change the second light beam into second polarized light.
5. The transmitting end according to claim 1, further comprising:
a random number generator configured to generate information to be transmitted.
6. The transmitting end of claim 1, wherein the polarization state of the first polarized light is one of an H-polarization state, a V-polarization state, a P-polarization state and an N-polarization state.
7. A receiving end for quantum communication, comprising:
a receiving telescope configured to receive the light beam from the transmitting end via free space;
a wavelength division multiplexer configured to split the quantum light and the beacon light from the received light beam;
an optical decoding unit configured to decode information to be transmitted from the quantum light;
an analyzer configured to split two orthogonal beams from the beacon light;
a photodetector configured to detect an incident light power of one of two orthogonal beams split from the beacon light;
a polarization controller configured to adjust a polarization reference for the received light beam in response to the detected incident light power not reaching a maximum, to change the detected incident light power by the adjusted polarization reference, and to implement offset compensation of a polarization state of the quantum light when the detected incident light power reaches a maximum.
8. The receiving end of claim 7, wherein the polarization controller is disposed between the receiving telescope and the wavelength division multiplexer.
9. The receiving end according to claim 7, wherein the decoding is based on the BB84 protocol.
10. The receiving end of claim 9, wherein the optical decoding unit comprises:
a first single photon detector configured to detect a photon having an H polarization state in the quantum light;
a second single photon detector configured to detect a photon having a V polarization state in the quantum light;
a third single photon detector configured to detect a photon having a P polarization state in the quantum light;
a fourth single photon detector configured to detect a photon having an N polarization state in the quantum light;
a first polarization beam splitter configured to split photons of the quantum light having an H polarization state to a first single photon detector and split photons of the quantum light having a V polarization state to a second single photon detector;
a second polarization beam splitter configured to split photons of the quantum light having a P polarization state to a third single photon detector and split photons of the quantum light having an N polarization state to a fourth single photon detector;
a beam splitter configured to split photons having an H polarization state and photons having a V polarization state in the quantum light to the first polarization beam splitter, and to split photons having a P polarization state and photons having an N polarization state in the quantum light to the second polarization beam splitter.
11. The receiving end according to claim 10, wherein the first single-photon detector, the second single-photon detector, the third single-photon detector, the fourth single-photon detector, the first polarization beam splitter, the second polarization beam splitter and the beam splitter are connected via polarization-maintaining fibers, and the polarization controller, the wavelength division multiplexer and the optical decoding unit are connected via polarization-maintaining fibers.
12. A system for quantum communication, comprising:
a transmitting end comprising:
the optical encoding unit is configured to prepare first polarized light and encode information to be transmitted by taking the polarization state of the first polarized light as a polarization reference so as to obtain quantum light comprising the information to be transmitted;
a beacon light preparation unit configured to prepare second polarized light, wherein a polarization state of the second polarized light is the same as a polarization state of the first polarized light;
a first wavelength division multiplexer configured to combine the second polarized light as beacon light and quantum light;
a transmitting telescope configured to transmit the combined quantum light and beacon light to a receiving end via free space, an
A receiving end, comprising:
a receiving telescope configured to receive the light beam from the transmitting end via free space;
a second wavelength division multiplexer configured to split the quantum light and the beacon light from the received light beam;
an optical decoding unit configured to decode information to be transmitted from the quantum light;
an analyzer configured to split two orthogonal beams from the beacon light;
a photodetector configured to detect an incident light power of one of two orthogonal beams split from the beacon light;
a polarization controller configured to adjust a polarization reference for the received light beam in response to the detected incident light power not reaching a maximum, to change the detected incident light power by the adjusted polarization reference, and to implement offset compensation of a polarization state of the quantum light when the detected incident light power reaches a maximum.
13. The system of claim 12, wherein the optical encoding unit comprises:
a first light source configured to emit a first light beam;
a first polarizer configured to change the first light beam into first polarized light;
a polarization state preparation unit configured to convert information to be transmitted into a polarization pulse having a predetermined polarization state with a polarization state of the first polarized light as a polarization reference, wherein the predetermined polarization state is one of an H-polarization state, a V-polarization state, a P-polarization state, and an N-polarization state;
and a decoy state preparation unit configured to perform decoy state processing on the polarized pulse to obtain quantum light.
14. The system of claim 12, wherein the beacon light preparation unit comprises:
a second light source configured to emit a second light beam;
a second polarizer configured to change the second light beam into second polarized light.
15. The system of claim 12, wherein the transmitting end further comprises:
a random number generator configured to generate information to be transmitted.
16. The system of claim 12, wherein the polarization state of the first polarized light is one of an H-polarization state, a V-polarization state, a P-polarization state, and an N-polarization state.
17. The system of claim 12, wherein the polarization controller is disposed between the receiving telescope and the wavelength division multiplexer.
18. The system of claim 12, wherein the optical decoding unit comprises:
a first single photon detector configured to detect a photon having an H polarization state in the quantum light;
a second single photon detector configured to detect a photon having a V polarization state in the quantum light;
a third single photon detector configured to detect a photon having a P polarization state in the quantum light;
a fourth single photon detector configured to detect a photon having an N polarization state in the quantum light;
a first polarization beam splitter configured to split photons of the quantum light having an H polarization state to a first single photon detector and split photons of the quantum light having a V polarization state to a second single photon detector;
a second polarization beam splitter configured to split photons of the quantum light having a P polarization state to a third single photon detector and split photons of the quantum light having an N polarization state to a fourth single photon detector;
a beam splitter configured to split photons having an H polarization state and photons having a V polarization state in the quantum light to the first polarization beam splitter, and to split photons having a P polarization state and photons having an N polarization state in the quantum light to the second polarization beam splitter.
19. The system of claim 18 wherein the first single photon detector, the second single photon detector, the third single photon detector, the fourth single photon detector, the first polarization beam splitter, the second polarization beam splitter, and the beam splitter are connected via polarization maintaining fiber, and wherein the polarization controller, the second wavelength division multiplexer, and the optical decoding unit are connected via polarization maintaining fiber.
20. The system according to any of claims 12 to 19, characterized in that the encoding and decoding is based on the BB84 protocol.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110415919.7A CN112994881B (en) | 2021-04-19 | 2021-04-19 | Transmitting end, receiving end and system for quantum communication |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110415919.7A CN112994881B (en) | 2021-04-19 | 2021-04-19 | Transmitting end, receiving end and system for quantum communication |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112994881A CN112994881A (en) | 2021-06-18 |
| CN112994881B true CN112994881B (en) | 2021-07-27 |
Family
ID=76340967
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110415919.7A Active CN112994881B (en) | 2021-04-19 | 2021-04-19 | Transmitting end, receiving end and system for quantum communication |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112994881B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6289104B1 (en) * | 1998-08-07 | 2001-09-11 | Ilinois Institute Of Technology | Free-space quantum cryptography system |
| CN202383526U (en) * | 2011-12-30 | 2012-08-15 | 哈尔滨理工大学 | Polarization tracking device in two-mirror model system |
| CN203761414U (en) * | 2014-04-17 | 2014-08-06 | 哈尔滨理工大学 | Quantum key distribution device based on polarization beacon tracking compensation |
| CN204392260U (en) * | 2015-03-12 | 2015-06-10 | 哈尔滨理工大学 | A kind of building area of a room sub-communication device based on beam expanding lens-level crossing-telescopic system |
-
2021
- 2021-04-19 CN CN202110415919.7A patent/CN112994881B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6289104B1 (en) * | 1998-08-07 | 2001-09-11 | Ilinois Institute Of Technology | Free-space quantum cryptography system |
| CN202383526U (en) * | 2011-12-30 | 2012-08-15 | 哈尔滨理工大学 | Polarization tracking device in two-mirror model system |
| CN203761414U (en) * | 2014-04-17 | 2014-08-06 | 哈尔滨理工大学 | Quantum key distribution device based on polarization beacon tracking compensation |
| CN204392260U (en) * | 2015-03-12 | 2015-06-10 | 哈尔滨理工大学 | A kind of building area of a room sub-communication device based on beam expanding lens-level crossing-telescopic system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112994881A (en) | 2021-06-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11387992B2 (en) | Transmitting device, receiving device, and quantum key distribution system | |
| CN107612690B (en) | Phase decoding method and device and quantum key distribution system | |
| US9246602B2 (en) | Quantum encryption communication apparatus, quantum encryption communication method, and quantum encryption communication system | |
| CN106161009B (en) | Quantum key distribution system based on time-phase encoding | |
| US8374350B2 (en) | Quantum communication system | |
| WO2018130052A1 (en) | Phase polarization multi-degree-of-freedom modulation qkd network system and method | |
| US8295485B2 (en) | Quantum communication system | |
| CN106856429B (en) | Quantum key distribution system and method based on receiving end polarization beam splitting | |
| US20060093143A1 (en) | Method and system for generating shared information | |
| CN106789048B (en) | Quantum key distribution system and method based on two-way single photon detection | |
| CN106850213B (en) | Quantum key distribution system and method | |
| CN106656494B (en) | Quantum key distribution system and method based on continuous photointerruption | |
| CN110620655B (en) | Polarization multiplexing bidirectional quantum key distribution method and system | |
| CN108540281B (en) | Quantum security direct communication system irrelevant to measuring equipment | |
| CN110620663A (en) | Quantum key distribution system for polarization and phase composite coding | |
| CN111565102B (en) | Quantum key distribution system based on free space | |
| CN110620619B (en) | Quantum communication system, transmitting end thereof and quantum communication method | |
| CN209517162U (en) | A kind of palarization multiplexing two-way quantum key dissemination system | |
| CN108183793A (en) | A kind of unrelated quantum key distribution system of multi-user's measuring apparatus and method | |
| CN112994881B (en) | Transmitting end, receiving end and system for quantum communication | |
| CN107135071B (en) | Quantum key distribution system and method based on time division multiplexing | |
| CN111756526B (en) | Quantum key distribution system, transmitting end, receiving end and communication method thereof | |
| CN211509059U (en) | Duplex polarization encoding quantum key distribution link | |
| Hasegawa et al. | Experimental decoy state quantum key distribution with unconditional security incorporating finite statistics | |
| CN213585800U (en) | Receiver of quantum communication system based on optical fiber connection |
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 |