CN216795004U - Light source tuning device for quantum communication system and quantum communication system - Google Patents
Light source tuning device for quantum communication system and quantum communication system Download PDFInfo
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- CN216795004U CN216795004U CN202220960060.8U CN202220960060U CN216795004U CN 216795004 U CN216795004 U CN 216795004U CN 202220960060 U CN202220960060 U CN 202220960060U CN 216795004 U CN216795004 U CN 216795004U
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Abstract
The utility model provides a light source tuning device for a quantum communication system and the quantum communication system, wherein the device comprises: a delayer electrically connected to the light source in the transmitting terminal; a first wavelength division multiplexer optically connected to an output end of the light source via an optical encoding unit in the transmitting end; the first controller is electrically connected to the delayer and used for obtaining the delay interval between the optical pulses from the receiving end and driving the delayer to adjust the delay position of the optical pulses according to the delay interval; a second wavelength division multiplexer optically connected to the first wavelength division multiplexer via an optical fiber; the single-photon detector is optically connected to the second wavelength division multiplexer through an optical decoding unit in the receiving end; and the second controller is electrically connected to the single photon detector, is used for measuring the time delay interval between the electric pulse signals and transmits the measured time delay interval to the transmitting end as the time delay interval between the optical pulses. The utility model can adjust and align the delay position of the optical pulse in real time under the condition of not interrupting the system coding and decoding.
Description
Technical Field
The utility model relates to the technical field of quantum communication, in particular to a light source tuning device for a quantum communication system and the quantum communication system.
Background
At present, in a quantum communication system (such as a quantum key distribution system), generally, at the time of system startup, an oscilloscope is used to display optical pulses prepared by a plurality of light sources in a transmitting end and align delay positions of the optical pulses in a manual adjustment manner, and then, a wavelength division multiplexer is used to combine the optical pulses and transmit the combined optical pulses from the transmitting end to a receiving end, so as to prevent an attacker from screening out key information carried by each optical pulse from the combined optical pulses according to the difference of the delay positions.
However, this way of using an oscilloscope to align the light pulses is not only costly (oscilloscope) but also time consuming and laborious (manual adjustment is required). In addition, even if the delay positions of the light pulses output by the light sources are aligned at the time of system startup, the delay positions of the light pulses output by the light sources vary with changes in ambient factors (such as vibration, etc.). This means that the delay positions of the light pulses output by the light sources need to be regularly aligned to ensure the security of the quantum key, and obviously, the alignment causes great inconvenience to the maintenance of the system.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a light source tuning device for a quantum communication system and the quantum communication system.
According to an aspect of the present invention, there is provided a light source tuning apparatus for a quantum communication system, the light source tuning apparatus comprising: the time delayer is electrically connected to the light source in the transmitting end of the quantum communication system and used for adjusting the time delay position of the light pulse output by the light source; a first wavelength division multiplexer optically connected to an output end of the light source via an optical encoding unit in a transmitting end of the quantum communication system, for combining the light pulses into the same optical fiber, and transmitting to a receiving end of the quantum communication system via the optical fiber; the first controller is electrically connected to the delayer and used for obtaining the delay interval between the optical pulses from the receiving end of the quantum communication system in a classical communication mode and driving the delayer to adjust the delay position of the optical pulses according to the delay interval; a second wavelength division multiplexer optically connected to the first wavelength division multiplexer via the optical fiber, for receiving the optical pulse to a receiving end of the quantum communication system and splitting the optical pulse; the single-photon detector is optically connected to the second wavelength division multiplexer through an optical decoding unit in a receiving end of the quantum communication system and is used for converting the separated optical pulses into electric pulse signals; and the second controller is electrically connected to the single-photon detector and used for measuring the time delay intervals among the electric pulse signals and transmitting the measured time delay intervals to the transmitting end of the quantum communication system as the time delay intervals among the optical pulses in a classical communication mode.
Preferably, the second controller is an FPGA chip.
Preferably, the FPGA chip measures the delay interval between the electrical pulse signals through a clock of the quantum communication system.
Preferably, the light source tuning apparatus further comprises: a time-to-digital converter electrically connected to the second controller, wherein the second controller measures a delay interval between the electrical pulse signals through the time-to-digital converter.
Preferably, the adjustment is made until the delay interval between the light pulses is zero.
According to another aspect of the present invention, there is provided a quantum communication system comprising the light source tuning apparatus for a quantum communication system as described above.
The light source tuning device for the quantum communication system and the quantum communication system provided by the utility model can adjust and align the delay positions of light pulses prepared by different light sources in real time under the condition of not interrupting the encoding and decoding of the quantum communication system, so that the beam combination precision of the quantum communication system is improved, and the safety of a quantum key is ensured.
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 quantum communication system comprising a light source tuning arrangement of the present invention for a quantum communication system.
Fig. 2 shows a schematic diagram of the delay intervals between light pulses measured using the light source tuning apparatus for a quantum communication system of the present invention.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Referring to fig. 1, the light source tuning apparatus for a quantum communication system of the present invention may include at least a time delay 101, a wavelength division multiplexer 102, a controller 103, a wavelength division multiplexer 104, a single photon detector 105, and a controller 106 shown in fig. 1.
In the light source tuning apparatus shown in fig. 1, a time delay 101 may be electrically connected to the light source in the transmitting end Alice of the quantum communication system shown in fig. 1, and may be used to adjust a time delay position of a light pulse output by the light source; the wavelength division multiplexer 102 may be optically connected to an output end of the light source via an optical encoding unit in Alice at a transmitting end of the quantum communication system shown in fig. 1, and may be configured to combine light pulses into the same optical fiber and transmit the light pulses to a receiving end Bob of the quantum communication system shown in fig. 1 via the optical fiber; the controller 103 may be electrically connected to the delayer 101, and may be configured to obtain a delay interval between the optical pulses from the receiving end Bob of the quantum communication system shown in fig. 1 in a classical communication manner, and drive the delayer 101 to adjust a delay position of the optical pulses according to the delay interval; the wavelength division multiplexer 104 may be optically connected to the wavelength division multiplexer 102 via an optical fiber, which may be used to receive optical pulses to the receiving end Bob of the quantum communication system shown in fig. 1 and to split the optical pulses; the single-photon detector 105 may be optically connected to the wavelength division multiplexer 104 through an optical decoding unit in the receiving end Bob of the quantum communication system shown in fig. 1, and may be configured to convert the split optical pulses into electrical pulse signals; the controller 106 may be electrically connected to the single photon detector 105, and may be configured to measure the delay intervals between the electrical pulse signals and transmit the measured delay intervals as delay intervals between the optical pulses to the transmitting end Alice of the quantum communication system shown in fig. 1 in a classical communication manner.
In one example, the controller 106 may be an FPGA chip. In this example, the FPGA chip may measure the delay interval between the electrical pulse signals through a clock of the quantum communication system.
In another example, the light source tuning apparatus shown in fig. 1 may further include a Time-to-Digital Converter (TDC). In this example, the time-to-digital converter may be electrically connected to the controller 106, and the controller 106 may measure the delay interval between the electrical pulse signals through the time-to-digital converter.
Next, the above-described adjustment process will be specifically described with reference to fig. 1 and 2.
Referring to fig. 2, Syn is a synchronization light pulse output by a synchronization light source at the transmitting end Alice of the quantum communication system shown in fig. 1, X0 is a phase base light pulse output by a phase-encoded light source at the transmitting end Alice of the quantum communication system shown in fig. 1, X1 is a phase base light pulse output by another phase-encoded light source at the transmitting end Alice of the quantum communication system shown in fig. 1, and Z is a time base light pulse output by a time-encoded light source at the transmitting end Alice of the quantum communication system shown in fig. 1.
In the delay interval shown in FIG. 2, T0The delay interval, T, between the synchronization light pulse Syn and the phase-based light pulse X0, measured by the controller 106 at the receiving end Bob of the quantum communication system shown in fig. 11Between the synchronization light pulse Syn and the phase-based light pulse X1 measured for the controller 106 at the receiving end Bob of the quantum communication system shown in fig. 1Delay interval, T2The delay interval between the synchronization light pulse Syn and the time base light pulse Z measured at the receiving end Bob of the quantum communication system shown in fig. 1 for the controller 106. The controller 103 may drive the delay unit 101 to adjust the delay positions of the synchronization optical pulse Syn, the phase-based optical pulse X0, the phase-based optical pulse X1, and the time-based optical pulse Z for these delay intervals until the above-mentioned delay interval measured by the controller 106 at the receiving end Bob of the quantum communication system shown in fig. 1 is zero.
By way of example and not limitation, the controller 103 may drive the retarder of the phase-coded light source corresponding to the phase-based light pulse X0 to adjust the retardation position of the phase-based light pulse X0 with the synchronization light pulse Syn as the reference light pulse until the delay interval T between the synchronization light pulse Syn and the phase-based light pulse X0 as measured by the controller 1060Zero time. Similarly, the controller 103 may adjust the delay position of the phase-based optical pulse X1 by using the synchronization optical pulse Syn as the reference optical pulse to drive the delay device of another phase-encoded light source corresponding to the phase-based optical pulse X1 until the delay interval T between the synchronization optical pulse Syn and the phase-based optical pulse X1 measured by the controller 1061Zero time. Similarly, the controller 103 may drive the delayer of the time-coded light source corresponding to the time-base light pulse Z to adjust the delay position of the time-base light pulse Z with the synchronization light pulse Syn as the reference light pulse until the delay interval T between the synchronization light pulse Syn and the time-base light pulse Z measured by the controller 1062Zero time.
By the above adjustment, the optical pulses Syn, X0, X1, and Z output by the light sources in the quantum communication system shown in fig. 1 can be aligned. Therefore, the beam combination precision of the quantum communication system can be improved, and the safety of the quantum key is ensured. In addition, even if the delay position of the optical pulse output by the light source changes due to changes in the surrounding environment (such as vibration), the light source tuning apparatus can adjust and align the delay position of the optical pulse output by each light source in real time according to the measured delay interval between the optical pulses without interrupting the encoding and decoding of the quantum communication system.
It should be understood that, although the quantum communication system shown in fig. 1 is a quantum communication system based on time phase coding, the present invention is not limited to this, and the light source tuning apparatus for a quantum communication system of the present invention can also be applied to adjust and align delay positions of light pulses output by light sources in real time in other types of quantum communication systems (e.g., based on polarization coding) as needed to improve beam combining accuracy of the quantum communication system and ensure security of a quantum key.
In addition, 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 claims.
Claims (5)
1. A light source tuning apparatus for a quantum communication system, comprising:
the time delayer is electrically connected to the light source in the transmitting end of the quantum communication system and used for adjusting the time delay position of the light pulse output by the light source;
a first wavelength division multiplexer optically connected to an output end of the light source via an optical encoding unit in a transmitting end of the quantum communication system, for combining the light pulses into the same optical fiber, and transmitting to a receiving end of the quantum communication system via the optical fiber;
the first controller is electrically connected to the delayer and used for obtaining the delay interval between the optical pulses from the receiving end of the quantum communication system in a classical communication mode and driving the delayer to adjust the delay position of the optical pulses according to the delay interval;
a second wavelength division multiplexer optically connected to the first wavelength division multiplexer via the optical fiber, for receiving the optical pulses to a receiving end of the quantum communication system and splitting the optical pulses;
the single-photon detector is optically connected to the second wavelength division multiplexer through an optical decoding unit in a receiving end of the quantum communication system and is used for converting the separated optical pulses into electric pulse signals; and
and the second controller is electrically connected to the single-photon detector and used for measuring the time delay intervals among the electric pulse signals and transmitting the measured time delay intervals to the transmitting end of the quantum communication system as the time delay intervals among the optical pulses in a classical communication mode.
2. The light source tuning apparatus of claim 1, wherein the second controller is an FPGA chip.
3. The light source tuning apparatus of claim 2, wherein the FPGA chip measures the delay interval between the electrical pulse signals via a clock of the quantum communication system.
4. The light source tuning apparatus of claim 1, further comprising:
a time-to-digital converter electrically connected to the second controller, wherein the second controller measures a delay interval between the electrical pulse signals through the time-to-digital converter.
5. A quantum communication system, comprising: a light source tuning arrangement for a quantum communication system as claimed in any one of claims 1 to 4.
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| CN202220960060.8U CN216795004U (en) | 2022-04-25 | 2022-04-25 | Light source tuning device for quantum communication system and quantum communication system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114826594A (en) * | 2022-07-01 | 2022-07-29 | 国开启科量子技术(北京)有限公司 | Light source optimum light-emitting position determining method and quantum random number generating device |
| CN115065419A (en) * | 2022-08-05 | 2022-09-16 | 国开启科量子技术(北京)有限公司 | Gating signal tuning method and device for quantum communication system |
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- 2022-04-25 CN CN202220960060.8U patent/CN216795004U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114826594A (en) * | 2022-07-01 | 2022-07-29 | 国开启科量子技术(北京)有限公司 | Light source optimum light-emitting position determining method and quantum random number generating device |
| CN114826594B (en) * | 2022-07-01 | 2022-11-08 | 国开启科量子技术(北京)有限公司 | Light source optimum light-emitting position determining method and quantum random number generating device |
| CN115065419A (en) * | 2022-08-05 | 2022-09-16 | 国开启科量子技术(北京)有限公司 | Gating signal tuning method and device for quantum communication system |
| CN115065419B (en) * | 2022-08-05 | 2022-11-15 | 国开启科量子技术(北京)有限公司 | Gating signal tuning method and device for quantum communication system |
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