SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a receiving terminal for quantum communication.
According to an aspect of the utility model provides a receiving terminal for quantum communication, the receiving terminal includes: a receiving telescope for receiving the light beam from the transmitting end via free space; a wavelength division multiplexer for splitting quantum light and beacon light from the received light beam; the analyzer is used for splitting two orthogonal beams of light from the beacon light; the photoelectric detector is used for detecting the incident light power of one of the two beams of light; a polarization controller for adjusting 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; the clock acquisition unit is used for converting the other light of the two beams of light into a synchronous electric signal as synchronous light so as to acquire a coding clock of the system; and an optical decoding unit for decoding the quantum light according to the encoding clock of the system.
Preferably, the receiving end further includes: and the phase-locked loop is used for performing phase locking and frequency multiplication on the synchronous electric signal so as to obtain a periodic gating signal synchronous with the coding clock of the system, wherein the optical decoding unit controls the single-photon detector to detect the quantum light through the periodic gating signal.
The utility model provides an above-mentioned receiving terminal for quantum communication can offset the compensation to the polarization state via free space received quantum light when acquireing the coding clock of system, not only can avoid acquireing and constructing extra light path or using extra optical device to the system clock like this, the lowering system implementation cost, but also can realize the offset compensation to the polarization state of quantum light under the condition of uninterrupted decoding to ensure the continuity of system one-tenth sign indicating number and the accuracy of system decoding.
According to the utility model discloses an on the other hand provides a receiving terminal for quantum communication, the receiving terminal includes: the positioning module is used for positioning the position of the transmitting end; a receiving telescope for receiving the light beam emitted from the position of the emitting end from the free space and transmitting the received light beam to the wavelength division multiplexer via the optical fiber; a wavelength division multiplexer for splitting quantum light and beacon light from the received light beam; the analyzer is used for splitting two orthogonal beams of light from the beacon light; a beacon light detection unit for detecting the intensity of one of the two beams of light; a controller that adjusts a relative position and/or attitude of the receiving telescope at the receiving end according to the detected intensity to change the detected intensity via the adjusted relative position and/or attitude, and determines that the quantum light is directed at the receiving end in response to the detected intensity reaching a maximum; the clock acquisition unit is used for converting the other light of the two beams of light into a synchronous electric signal as synchronous light so as to acquire a coding clock of the system; and an optical decoding unit for decoding the quantum light according to the encoding clock of the system.
Preferably, the receiving end further includes: and the phase-locked loop is used for performing phase locking and frequency multiplication on the synchronous electric signal so as to obtain a periodic gating signal synchronous with the coding clock of the system, wherein the optical decoding unit controls the single-photon detector to detect the quantum light through the periodic gating signal.
The utility model provides an above-mentioned receiving terminal for quantum communication can ensure quantum light in real time, accurately launch the receiving terminal when the coding clock who acquires the system, not only can avoid acquireing and constructing extra light path or using extra optical device to the system clock like this, and the cost is realized to the low system, but also can improve the accuracy of optics decoding to a great extent.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Referring to fig. 1, a receiving end for quantum communication of the present invention may include a receiving telescope 110, a wavelength division multiplexer 120, an analyzer 130, a photodetector 140, a polarization controller 150, a clock acquisition unit 160, and an optical decoding unit 170.
In the receiving end shown in fig. 1, a receiving telescope 110 is used to receive the light beam from the transmitting end via free space; the wavelength division multiplexer 120 is configured to split the quantum light and the beacon light from the received light beam; the analyzer 130 is configured to split two orthogonal beams from the beacon light; the photodetector 140 is configured to detect an incident light power of one of the two beams; the polarization controller 150 is 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 for a polarization state of the quantum light when the detected incident light power reaches a maximum; the clock obtaining unit 160 is configured to convert the other of the two beams of light into a synchronous electrical signal as a synchronous light to obtain a coding clock of the system (i.e., a coding clock of the transmitting end); the optical decoding unit 170 is used to decode the quantum light according to the encoding clock of the system.
In addition, in the receiving end shown in fig. 1, a phase-locked loop (not shown) may be further included for performing phase locking and frequency multiplication on the synchronous electrical signal to obtain a periodic gating signal synchronized with an encoding clock of the system, and the optical decoding unit 170 controls the single-photon detector (not shown) to detect the quantum light through the periodic gating signal. For example, in the case where the beacon light is a low frequency light, a synchronous electrical signal, for example, but not limited to, having a frequency of 100 kHz, may be converted to a periodic gating signal, for example, but not limited to, having a frequency of 125 MHz, by a phase locked loop as previously described, such that the quantum communication system operates at a high frequency.
By using the receiving end shown in fig. 1, the polarization state of the quantum light received via the free space can be offset-compensated while the encoding clock of the system is acquired, so that not only can an additional optical path or an additional optical device be avoided for acquiring the system clock, and the system implementation cost be reduced, but also the offset compensation of the polarization state of the quantum light can be implemented without interrupting the decoding, so as to ensure the continuity of system code formation and the accuracy of system decoding.
Referring to fig. 2, a receiving end for quantum communication of the present invention may include a positioning module 210, a receiving telescope 220, a wavelength division multiplexer 230, a polarization analyzer 240, a beacon light detection unit 250, a controller 260, a clock acquisition unit 270, and an optical decoding unit 280.
In the receiving end shown in fig. 2, the positioning module 210 is used to position the transmitting end; the receiving telescope 220 is used for receiving the light beam emitted from the position of the emitting end from the free space and transmitting the received light beam to the wavelength division multiplexer 230 via the optical fiber; the wavelength division multiplexer 230 is used for splitting the quantum light and the beacon light from the received light beam; the analyzer 240 is configured to split two orthogonal beams from the beacon light; the beacon light detection unit 250 is configured to detect the intensity of one of the two beams; the controller 260 is configured to adjust the relative position and/or orientation of the receiving telescope 220 at the receiving end according to the detected intensity, to change the detected intensity via the adjusted relative position and/or orientation, and to determine that the quantum light is directed at the receiving end in response to the detected intensity reaching a maximum; the clock obtaining unit 270 is configured to convert the other of the two beams of light into a synchronous electrical signal as a synchronous light to obtain a coding clock of the system (i.e., a coding clock of the transmitting end); and an optical decoding unit 280 for decoding the quantum light according to the encoding clock of the system.
In addition, in the receiving end shown in fig. 2, a phase-locked loop (not shown) may be further included, and the phase-locked loop is configured to perform phase locking and frequency multiplication on the synchronous electrical signal to obtain a periodic gating signal synchronized with an encoding clock of the system, and the optical decoding unit 280 controls a single photon detector (not shown) to detect the quantum light through the periodic gating signal. For example, in the case where the beacon light is a low frequency light, a synchronous electrical signal, for example, but not limited to, having a frequency of 100 kHz, may be converted to a periodic gating signal, for example, but not limited to, having a frequency of 125 MHz, by a phase locked loop as previously described, to enable the system to operate at high frequencies.
By using the receiving end shown in fig. 2, the quantum light can be ensured to be accurately emitted to the receiving end in real time while the encoding clock of the system is acquired, so that not only can an extra light path or an extra optical device be avoided from being constructed for acquiring the system clock, the system implementation cost is reduced, but also the accuracy of optical decoding can be improved to a great extent.
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.