CN214480629U - Pulse light source for time phase coding and coding device - Google Patents
Pulse light source for time phase coding and coding device Download PDFInfo
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- CN214480629U CN214480629U CN202120851691.1U CN202120851691U CN214480629U CN 214480629 U CN214480629 U CN 214480629U CN 202120851691 U CN202120851691 U CN 202120851691U CN 214480629 U CN214480629 U CN 214480629U
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Abstract
The utility model discloses a need not encoding device that can be used to time phase place of interferometer encodes, relate to the quantum communication field, including the main laser, from the laser, optical transmission element, phase modulator and intensity modulator, wherein, the main laser is configured to prepare the duty cycle and is greater than the first pulse light of settlement threshold value, from the laser configuration to prepare the second pulse light according to first pulse light, phase modulator is configured to carry out phase coding to the second pulse light, make phase difference between two continuous pulse lights in the second pulse light keep at 0 or, intensity modulator is configured to be according to the pulse light of second pulse light preparation trap attitude, security performance and stability have been improved, complexity and cost have been reduced. In addition, the invention also discloses a pulse light source for time phase coding.
Description
Technical Field
The utility model relates to a quantum communication field, concretely relates to pulsed light source and coding device that can be used to time phase place coding.
Background
In order to improve the code forming rate and the code forming distance of the quantum key distribution system and realize the stability of resisting external environment disturbance, the quantum key distribution system based on time phase coding is mainly adopted at present. The current quantum key distribution system based on time phase coding mainly comprises the following two types:
(1) the problem of inconsistent output wavelength is solved by combining a plurality of paths of master lasers and a path of slave lasers;
(2) the method combines one path of main laser and two paths of slave lasers to solve the problem of how to prepare a plurality of unequal arm interferometers with matched lengths based on optical fibers or planar optical waveguides.
These two solutions have the following drawbacks:
(1) although an injection locking mode is adopted, the pulse light output by the multi-path main laser cannot be completely the same in width or amplitude due to the influence of an internal hardware structure of the multi-path main laser, so that the output wavelengths of the multi-path main laser cannot be completely the same, so that the scheme cannot effectively ensure the consistency of the output wavelengths of the multi-path main laser, and the safety performance of the conventional quantum key distribution system based on time phase coding is not high;
(2) the interferometer is required to carry out phase coding, the interference effect between the interferometer and the receiver is poor due to the fact that the interferometer is easily affected by external temperature, and constant-temperature and anti-seismic design needs to be carried out on the interferometer in a large-scale quantum communication network, so that the existing quantum key distribution system based on time phase coding is high in complexity, high in cost and poor in stability.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a can be used to time phase coding's pulsed light source and coding device for solve the output wavelength uniformity that prior art exists can not effectively guarantee multichannel laser instrument, security performance low, the complexity is high, with high costs, the poor stability's defect.
In order to achieve the above object, in a first aspect, the present invention provides a pulsed light source for time phase encoding, including:
a main laser configured to prepare first pulsed light having a duty ratio larger than a set threshold;
a slave laser configured to prepare a second pulsed light from the first pulsed light, wherein the second pulsed light includes a front pulsed light, a back pulsed light, and two continuous pulsed lights.
As a preferred embodiment of the present invention, the master laser is further configured to injection-lock the first pulsed light as seed light.
As a preferred embodiment of the present invention, the first pulse light is periodic light with a duty ratio of 50%.
As a preferred embodiment of the present invention, the time code of the front pulse light is Z0.
As a preferred embodiment of the present invention, the time code of the back pulse light is Z1.
As a preferred embodiment of the present invention, the pulsed light source further includes an optical transmission element, wherein the master laser injects the first pulsed light into the slave laser through the optical transmission element.
As a preferred embodiment of the present invention, the optical transmission element is a circulator.
In a second aspect, the present invention provides an interferometer-free encoding apparatus for time phase encoding, including the pulsed light source according to the first aspect.
As a preferred embodiment of the present invention, the encoding apparatus further includes a phase modulator, wherein the phase modulator is configured to perform phase encoding on the second pulsed light, so that a phase difference between two consecutive pulsed lights in the second pulsed light is maintained at 0 or pi.
As a preferred embodiment of the present invention, the encoding apparatus further includes an intensity modulator, wherein the intensity modulator is configured to prepare the pulsed light in the signal state and the pulsed light in the decoy state according to the second pulsed light.
As a preferred embodiment of the present invention, the phase of two consecutive pulse lights with a phase difference of 0 in the second pulse light is encoded as X0 or Y0.
As a preferred embodiment of the present invention, the phase of two consecutive pulse lights with a phase difference of 1 in the second pulse light is encoded as X1 or Y1.
The embodiment of the utility model provides a quantum key distribution system's sending terminal and be used for pulsed light source, the coding device of this sending terminal to have following beneficial effect:
(1) the design of the sending end of the quantum key distribution system based on time phase coding is realized through a single-path laser in the true sense, the consistency of the output wavelength of the laser in the sending end of the quantum key distribution system based on time phase coding can be effectively ensured, and the safety performance is higher;
(2) phase encoding is carried out without adopting an unequal arm interferometer or a Michelson interferometer, so that the complexity and the cost of a quantum key distribution system based on time phase encoding are reduced, and the stability is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a transmitting end of a conventional time phase coding-based quantum key distribution system;
fig. 2 is a schematic structural diagram of a transmitting end of another existing quantum key distribution system based on time phase coding;
fig. 3 is a schematic structural diagram of a pulse light source for time phase encoding according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of an encoding apparatus that can be used for time phase encoding without an interferometer according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a structure of a transmitting end of the quantum key distribution system provided by the embodiment of the present invention;
fig. 6 is a schematic diagram illustrating an operation principle of an encoding apparatus that can be used for time phase encoding without an interferometer according to an embodiment of the present invention;
fig. 7 is a schematic diagram of pulsed light output by an intensity modulator based on a sending end of a time phase coding quantum key distribution system provided by the embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings in the embodiments of the present invention are combined below to clearly and completely describe the technical solutions in the embodiments of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
As shown in fig. 1, a transmitting end of a conventional time-phase-coding-based quantum key distribution system includes a master laser 10, a master laser 11, a master laser 12, a slave laser 13, an unequal arm interferometer 14, and an optical transmission element 15, and divides pulsed light generated by the master laser 10 into two pulsed lights by the unequal arm interferometer 14 and injects the two pulsed lights into the master laser 11 and the master laser 12, respectively. In this scheme, the main laser 11 and the main laser 12 can operate in the injection locking mode based on the seed light output from the main laser 10, but due to the influence of the internal hardware structure of the main laser 11 and the main laser 12 and the influence of factors such as the unequal arm interferometer, the consistency of the output wavelengths of the main laser 11 and the main laser 12 cannot be effectively ensured even if the injection locking mode is adopted, so that the security performance of the time-phase encoding-based quantum key distribution system according to this scheme is not high.
As shown in fig. 2, a transmitting end of another existing time-phase-coding-based quantum key distribution system includes a master laser 1-1, a slave laser 1-2, a slave laser 1-3, a synchronous optical detector 1-4, an unequal arm interferometer 1-25, a first circulator 1-7, a second circulator 1-8, a first beam splitter 1-9, a filter 1-10, an attenuator 1-11, and a wavelength division multiplexer 1-12, and the transmitting end uses the unequal arm interferometer 1-25 to temporally divide the master pulse light emitted from the master laser 1-1 into two identical pulse lights and injection-lock the two identical pulse lights to the slave laser 1-2 and the slave laser 1-3, respectively, so as to generate a slave laser pulse. When the master pulse light is injected, different voltages are triggered to the slave laser 1-2 and the slave laser 1-3 respectively, so that the slave laser 1-2 and the slave laser 1-3 emit slave pulse lights with different intensities, and on the basis of the reason that the time phase coding based quantum key distribution system shown in fig. 1 cannot effectively ensure the consistency of the output wavelengths of the master laser 11 and the master laser 12, the scheme cannot effectively ensure the consistency of the output wavelengths of the slave laser 1-2 and the slave laser 1-3, so that the safety performance of the time phase coding based quantum key distribution system related to the scheme is not high.
The following is a detailed description of the pulsed light source for time phase encoding provided by the embodiments of the present invention:
as a specific embodiment of the present invention, as shown in fig. 3, a pulse light source for time coding and phase coding includes a master laser, a slave laser, and an optical transmission element. Wherein:
the master laser is configured to prepare first pulse light with a duty ratio larger than a set threshold value according to a master driving signal emitted by the master control unit and inject the first pulse light into the slave laser as seed light.
As a specific embodiment of the utility model, utilize main laser to pour into the locking into to first pulsed light to guarantee that this first pulsed light wavelength can not change in transmission process. As shown in fig. 6, the first pulse light output by the main laser is periodic light with a duty ratio of 50%. The duty ratio is the ratio of the time occupied by the pulse in one system period to the total time corresponding to the system period.
And the slave laser is configured to prepare a second pulse light according to the first pulse light and a slave driving signal emitted by the main control unit. The second pulse light comprises a front pulse light, a rear pulse light and two continuous pulse lights.
As shown in FIG. 6, each pulse in the first pulse light occupies a time T1Is longer than the time T occupied by each pulse in the second pulse light2So that it is advantageous to subsequently generate two pulsed lights whose phase difference is maintained at 0 or pi continuously. In the injection locking mode, the phase difference between two continuous pulse lights in the second pulse light is maintained at 0.
Because the embodiment of the utility model provides a pulse light source based on time phase coding quantum key distribution system only includes main laser instrument all the way and follows the laser instrument all the way, so, compare in three routes main laser instrument in the pulse light source shown in figure 1 and follow laser instrument all the way and two way main laser instrument and two way from the laser instrument in shown pulse light source in figure 2 all the way, the embodiment of the utility model provides an can be used to the pulse light source of time phase coding can effectively guarantee the uniformity of the output wavelength of laser instrument, and the security performance is better.
As an alternative embodiment of the present invention, the time code of the front pulse light is Z0, and the time code of the back pulse light is Z1.
As an alternative embodiment of the present invention, the optical transmission element is a circulator having port 1, port 2 and port 3. The pulse light output from the master laser enters through port 1 of the circulator and is injected into the slave laser through port 2, and the pulse light output from the slave laser is output through port 3.
As shown in fig. 4, the embodiment of the present invention further provides an interferometer-free encoding apparatus for time phase encoding, which includes a phase modulator and an intensity modulator in addition to the pulsed light source based on the time phase encoded quantum key distribution system shown in fig. 3.
Wherein the phase modulator is configured to phase encode the second pulsed light, and the intensity modulator is configured to prepare the pulsed light of the signal state and the pulsed light of the decoy state as shown in fig. 7 from the second pulsed light.
Wherein such a phase difference between two successive pulsed lights in the second pulsed light may be utilized to indicate that the two pulsed lights are phase-encoded.
As an alternative embodiment of the present invention, under the X basis vector, the phase code of two consecutive pulses with a fixed phase difference of 0 is denoted as X0, and the phase code of two consecutive pulses with a fixed phase difference is denoted as X1; under the Y basis vector, the phase encoding of two consecutive pulses with a fixed phase difference of 0 is represented as Y0, and the phase encoding of two consecutive pulses with a fixed phase difference is represented as Y1.
The embodiment of the utility model provides a need not encoding device that can be used to time phase coding of interferometer includes the main laser, from the laser, optical transmission element, phase modulator and intensity modulator, wherein, the main laser is configured to prepare the duty cycle and is greater than the first pulsed light of settlement threshold value, from the laser configuration to prepare the second pulsed light according to first pulsed light, phase modulator is configured to carry out phase coding to the second pulsed light, make phase difference between two continuous pulsed lights in the second pulsed light maintain 0 or, intensity modulator is configured to lure attitude pulsed light according to second pulsed light preparation, security performance and stability have been improved, complexity and cost have been reduced.
As shown in fig. 5, the embodiment of the present invention further provides a transmitting end of a quantum key distribution system, where the transmitting end includes an encoding apparatus that can be used for phase encoding and that does not need an interferometer, as shown in fig. 4.
As a specific embodiment of the present invention, the master laser, the slave laser, the optical transmission element, the phase modulator and the intensity modulator are all connected by polarization maintaining optical fibers.
It will be appreciated that the relevant features of the method and apparatus described above are referred to one another. In addition, "first", "second", and the like in the above embodiments are for distinguishing the embodiments, and do not represent merits of the embodiments.
The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
It should be noted that the above-mentioned embodiments do not limit the present invention in any way, and all technical solutions obtained by adopting equivalent replacement or equivalent transformation fall within the protection scope of the present invention.
Claims (12)
1. A pulsed optical source for time phase encoding, comprising:
a main laser configured to prepare first pulsed light;
a slave laser configured to prepare a second pulsed light from the first pulsed light, wherein the second pulsed light includes a front pulsed light, a rear pulsed light, and two continuous pulsed lights;
the time T occupied by each pulse in the first pulse light1Is longer than the time T occupied by each pulse in the second pulse light2。
2. The pulsed optical source for time-phase encoding according to claim 1, wherein:
the primary laser is further configured to injection-lock the first pulsed light as seed light.
3. The pulsed optical source for time-phase encoding according to claim 1, wherein:
the first pulse light is periodic light with a duty ratio of 50%.
4. A pulsed optical source for time-phase encoding according to claim 1, wherein:
the time code of the front pulse light is Z0.
5. A pulsed optical source for time-phase encoding according to claim 1, wherein:
the time code of the back pulse light is Z1.
6. A pulsed optical source for time-phase encoding according to any one of claims 1-5, characterized in that:
further comprising an optical transmission element, wherein the master laser injects the first pulsed light into the slave laser through the optical transmission element.
7. A pulsed optical source for time-phase encoding according to claim 6, wherein:
the optical transmission element is a circulator.
8. An interferometer-free encoding device that can be used for time phase encoding, comprising a pulsed light source according to any one of claims 1 to 7.
9. The interferometer-less encoding apparatus usable for time-phase encoding according to claim 8, wherein:
further comprising a phase modulator, wherein the phase modulator is configured to phase encode the second pulsed light such that a phase difference between two consecutive pulsed lights of the second pulsed light is maintained at 0 or pi.
10. The interferometer-less encoding apparatus usable for time-phase encoding according to claim 8, wherein:
the pulse light source further comprises an intensity modulator, wherein the intensity modulator is configured to prepare a signal-state pulse light and a decoy-state pulse light according to the second pulse light.
11. The interferometer-less encoding apparatus usable for time-phase encoding according to claim 9, wherein:
the phase of two consecutive pulse lights with a phase difference of 0 in the second pulse light is encoded as X0 or Y0.
12. The interferometer-less encoding apparatus usable for time-phase encoding according to claim 9, wherein:
the phase of two consecutive pulse lights with a phase difference of 1 in the second pulse light is encoded as X1 or Y1.
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| CN202120851691.1U CN214480629U (en) | 2021-04-25 | 2021-04-25 | Pulse light source for time phase coding and coding device |
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| CN202120851691.1U CN214480629U (en) | 2021-04-25 | 2021-04-25 | Pulse light source for time phase coding and coding device |
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