CN111327369B - Frequency domain multiplexing quantum channel basic link of optical fiber communication waveband - Google Patents
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Abstract
The invention relates to a frequency domain multiplexing quantum channel basic link of an optical fiber communication waveband, which adopts a frequency domain broadband entanglement light source to output entangled photon pairs at a high speed; then, the photon-quantum memory entanglement is established at a high speed through the storage effect of the multi-channel quantum memory on photons of a plurality of frequency channels; quantum entanglement among the multi-channel quantum memories is established at a high speed in a declared form by a multi-channel bell state measuring device; finally, according to the result of the multi-channel Bell state measurement, the multi-channel quantum memory can output entangled photon pairs with identical frequencies at a high rate, so that the fidelity and the transmission rate of quantum bit transmission in the quantum channel can be improved. All devices used by the invention can be from mature photoelectronic devices, which is beneficial to system assembly preparation and practical development, and the whole device has the characteristics of easy assembly, miniaturization, practicability and integration of optical fiber devices.
Description
Technical Field
The invention belongs to the field of quantum information, and particularly relates to a frequency domain multiplexing quantum channel basic link of an optical fiber communication waveband.
Background
The quantum channel interconnects quantum nodes or quantum computers on the full quantum information level, and is the key for constructing future quantum networks. The high-fidelity and high-speed quantum bit transmission is a core task for constructing a quantum channel, and is mainly realized by the technologies of quantum entanglement distribution, quantum invisible state transmission and the like. Photons with wavelengths in the optical fiber communication band have relatively small loss when transmitted in an optical fiber, and thus the optical fiber is an important medium for photon transmission in the current quantum channel research. Although in the metro range, the optical fiber loss does not have a significant influence on quantum entanglement distribution, after the optical fiber connection between nodes in a sub-network exceeds a certain length, the entanglement distribution rate is sharply reduced by the loss caused by the optical fiber, and further, the fidelity and the transmission rate of quantum bit transmission in a quantum channel are limited. Quantum relaying is an ideal solution to this problem. In this scheme, the quantum channel connecting two distant end nodes is divided into several elementary links. In each basic link, entanglement between photons output by two ends of the basic link is established through an entanglement photon source, a quantum memory, an optical fiber and a Bell state measuring device, then entanglement among photons output by different basic links is realized by using an entanglement exchange method, and finally quantum entanglement among photons output by two terminal nodes of a quantum channel is realized.
In the current implementation scheme of the quantum channel basic link, a frequency domain single-mode entanglement light source and a single-channel bell state detection device are both adopted, so that the rate of entanglement established at two ends of the basic link is low, and the transmission rate and the fidelity of quantum bits in the quantum channel based on the link are still not high. In view of the problem, the invention provides a frequency domain multiplexing quantum channel basic link of an optical fiber communication waveband, in the basic link, photon entanglement at two ends of the link can be established at a higher speed by utilizing a frequency domain broadband entanglement light source, a multi-channel quantum memory and a multi-channel Bell state detection device, so that the fidelity and the speed of quantum bit transmission in a quantum channel are improved, and the practicability of an optical fiber communication waveband quantum network is promoted.
Disclosure of Invention
The invention aims to solve the technical problem in the prior art and provides a frequency domain multiplexing quantum channel basic link of an optical fiber communication waveband.
In order to solve the above technical problem, an embodiment of the present invention provides a frequency domain multiplexing quantum channel basic link of an optical fiber communication band, including a first multi-channel quantum memory, a second multi-channel quantum memory, a first frequency domain broadband entangled light source, a second frequency domain broadband entangled light source, and a multi-channel bayer pattern measuring apparatus; the multi-channel Bell state measuring device comprises a first dense wavelength division demultiplexer, a second dense wavelength division demultiplexer, an optical fiber coupler, n pairs of single photon detectors (n is a positive integer) and n coincidence logic circuits;
the first path of photons output by the optical fiber coupler enters a second dense wavelength division demultiplexer through the optical fiber and then outputs first idler photons of n frequency modes, the second path of photons output by the optical fiber coupler enters the first dense wavelength division demultiplexer through the optical fiber and then outputs second idler photons of n frequency modes, the first idler photons of n frequency modes are respectively detected by n single photon detectors, the second idler photons of n frequency modes are respectively detected by the other n single photon detectors, the first idler photons and the second idler photons of the same frequency mode are respectively detected by a pair of single photon detectors and then generate corresponding coincidence logic signals, the coincidence logic circuit performs analog-to-digital conversion, delay and logic operation on the input electric pulse signal, then completes Bell state measurement, outputs an entanglement declaration signal, and the entanglement declaration signal enters a first multi-channel quantum memory and a second multi-channel quantum memory;
frequency domain broadband signal photons generated by the first frequency domain broadband entanglement light source and the second frequency domain broadband entanglement light source respectively enter the first multi-channel quantum memory and the second multi-channel quantum memory, and the first multi-channel quantum memory and the second multi-channel quantum memory generate and output entanglement photon pairs with identical frequencies according to input entanglement announcement signals.
On the basis of the technical scheme, the invention can be further improved as follows.
Furthermore, the first multi-channel quantum memory and the second multi-channel quantum memory have the same structure and comprise a first laser source, a first phase modulator, an intensity modulator, a circulator, an erbium-doped optical waveguide at the temperature of the refrigerator, a dense wavelength division multiplexer, a third dense wavelength division demultiplexer, a second phase modulator and a frequency shift electric signal generating module;
the first laser source is connected with a first port of the circulator through the first phase modulator and the intensity modulator in sequence, frequency domain broadband signal photons output signal photons of n frequency modes through the third dense wavelength division demultiplexer, the signal photons of the n frequency modes output frequency domain multimode signal photons through the dense wavelength division multiplexer, the frequency domain multimode signal photons are connected with a second port of the circulator through the erbium-doped optical waveguide at the temperature of the refrigerator, a third port of the circulator is connected with an optical input end of the second phase modulator, the entanglement announcement signal is connected with an electrical signal input end of the second phase modulator through the frequency shift electrical signal generation module, and an output end of the second phase modulator is used for outputting frequency identical photons.
Further, the first frequency domain broadband entanglement light source and the second frequency domain broadband entanglement light source have the same structure, and comprise a second laser source, an optical amplifier, a polarization controller, a variable optical attenuator, a band-pass filter, a nonlinear optical medium, a notch filter and a wavelength selection device;
the second laser source is connected with the input end of the wavelength selection device through the optical amplifier, the polarization controller, the variable optical attenuator, the band-pass filter, the nonlinear optical medium and the notch filter in sequence, and the wavelength selection device outputs frequency domain broadband idler photons and frequency domain broadband signal photons respectively.
Further, the single photon detector is a semiconductor avalanche detector or a superconducting nanowire single photon detector.
Further, the laser source is a solid laser, a gas laser, a semiconductor laser or a dye laser.
Further, the phase modulator is a phase modulator using KDP crystal or lithium niobate crystal as electro-optical crystal.
Further, the erbium-doped optical waveguide at the temperature of the refrigerator is an erbium-doped lithium niobate crystal waveguide, an erbium-doped optical fiber or an erbium-doped yttrium silicate crystal waveguide.
Further, the polarization controller is a slide type polarization controller or a fiber ring type polarization controller.
Further, the nonlinear optical medium is a periodically polarized lithium niobate crystal, a periodically polarized potassium titanyl phosphate crystal or a periodically polarized barium metaborate crystal.
Further, the intensity modulator is based on acousto-optic effect or electro-optic effect.
The invention has the beneficial effects that: according to the frequency domain multiplexing quantum channel basic link of the optical fiber communication waveband, the entangled photon pair is output at a high speed by adopting a frequency domain broadband entangled light source; then, the photon-quantum memory entanglement is established at a high speed through the storage effect of the multi-channel quantum memory on photons of a plurality of frequency channels; quantum entanglement among the multi-channel quantum memories is established at a high speed in a declared form by a multi-channel bell state measuring device; finally, according to the result of the multi-channel Bell state measurement, the multi-channel quantum memory can output entangled photon pairs with identical frequencies at a high rate, so that the transmission rate and the fidelity of quantum bits in the quantum channel can be improved. Meanwhile, all devices used by the frequency domain multiplexing quantum channel basic link of the optical fiber communication waveband can be from mature optoelectronic devices, system assembly preparation and practical development are facilitated, and the whole device has the characteristics of easiness in assembly, miniaturization, practicability and integration of optical fiber devices.
Drawings
Fig. 1 is a schematic structural diagram of a frequency domain multiplexing quantum channel basic link of an optical fiber communication band according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a multi-channel quantum memory according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a frequency-domain broadband entanglement light source according to an embodiment of the invention;
fig. 4 is a structural diagram of an atomic frequency comb experimentally prepared in an erbium-doped optical waveguide at the temperature of a refrigerator.
In the drawings, the components represented by the respective reference numerals are listed below:
81. 91, 82, 92.. 8n, 9 n: n pairs of single photon detectors, n being a positive integer, 101, 102 … 10 n: n coincidence logic circuits, H1、H2…Hn: n channel numbers of entanglement announcement signals, 1, a first multi-channel quantum memory, 2, a first frequency domain broadband entanglement light source, 3, a first dense wavelength division demultiplexer, 4, a fiber coupler, 5, a second dense wavelength division demultiplexer, 6, a second frequency domain broadband entanglement light source, 7, a second multi-channel quantum memory, 11, a first laser source, 12, a first phase modulator, 13, an intensity modulator, 14, a circulator, 15, an erbium-doped optical waveguide at the temperature of a refrigerator, 16, the optical fiber laser comprises a dense wavelength division multiplexer, 17, a second phase modulator, 18, a frequency shift electric signal generating module, 19, a second laser source, 20, an optical amplifier, 21, a polarization controller, 22, an adjustable optical attenuator, 23, a nonlinear optical medium, 24, a notch filter, 25, a wavelength selection device, 26, a third dense wavelength division demultiplexer, 27 and a band-pass filter.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
As shown in fig. 1, a frequency domain multiplexing quantum channel basic link of an optical fiber communication waveband according to an embodiment of the present invention includes a first multi-channel quantum memory 1, a second multi-channel quantum memory 7, a first frequency domain broadband entangled light source 2, a second frequency domain broadband entangled light source 6, and a multi-channel bayer pattern measuring apparatus; the multi-channel Bell state measuring device comprises a first dense wavelength division demultiplexer 3, a second dense wavelength division demultiplexer 5, a fiber coupler 4, n pairs of single photon detectors 81, 91, 82, 92.. 8n and 9n, wherein n is a positive integer, and n coincidence logic circuits 101 and 102 … 10 n;
the frequency domain broadband idler photons omega generated by the first frequency domain broadband entanglement light source 2 and the second frequency domain broadband entanglement light source 6iThe photons enter the optical fiber coupler 4 through the optical fiber to generate two-photon interference, and the first path of photons output by the optical fiber coupler 4 enter the second dense wavelength division demultiplexer 5 through the optical fiber and then output first idler photons omega with n frequency modesi11…ωi1nThe second path of photons output by the optical fiber coupler 4 enters the first dense wavelength division demultiplexer through the optical fiberAfter 3, outputting n frequency modes of second idler photons omegai21…ωi2nFirst idler photons of n frequency modes are respectively detected by n single-photon detectors, second idler photons of n frequency modes are respectively detected by another n single-photon detectors, after the first idler photons and the second idler photons of the same frequency mode are respectively detected by a pair of single-photon detectors, generated electric pulse signals enter corresponding coincidence logic circuits, the coincidence logic circuits perform analog-to-digital conversion, delay and logic operation on the input electric pulse signals to complete Bell state measurement, an entanglement announcement signal is output, and the entanglement announcement signal enters a first multi-channel quantum memory 1 and a second multi-channel quantum memory 7;
the frequency domain broadband signal photons omega generated by the first frequency domain broadband entanglement light source 2 and the second frequency domain broadband entanglement light source 6sRespectively enter a first multi-channel quantum memory 1 and a second multi-channel quantum memory 7, and the first multi-channel quantum memory 1 and the second multi-channel quantum memory 7 generate and output entangled photon pairs with identical frequencies according to input entangled declaration signals.
In the above embodiment, the first frequency-domain broadband-entangled light source 2 and the second frequency-domain broadband-entangled light source 6 output the frequency-domain broadband signal photon ωsSum frequency domain broadband idler photon omegaiAre entangled photon pairs. Since the entangled-photon pairs are generated and output over a wide frequency range, the first frequency-domain broadband entanglement light source 2 and the second frequency-domain broadband entanglement light source 6 can output the entangled-photon pairs at a high rate.
The frequency domain broadband signal photon omega output by the first frequency domain broadband entanglement light source 2sAfter being input into the first multi-channel quantum memory 1, the multi-channel quantum memory is transformed into frequency-domain multi-mode signal photons through a filtering and wavelength division multiplexing process, and then is coherently stored in the first multi-channel quantum memory 1. The process establishes the frequency domain broadband idler photon omega output by the first multi-channel quantum memory 1 and the first frequency domain broadband entanglement light source 2 at a high speediQuantum entanglement between them. The frequency domain broadband signal photon omega output by the second frequency domain broadband entanglement light source 6sAfter being input into the second multi-channel quantum memory 7, the data is converted into the data through the filtering and wavelength division multiplexing processesThe frequency domain multimode signal photons are then coherently stored in a second multi-channel quantum memory 7. The process establishes the frequency domain broadband idler photon omega output by the second multi-channel quantum memory 7 and the first frequency domain broadband entanglement light source 6 at a high speediQuantum entanglement between them.
The first dense wavelength division demultiplexer 3 and the second dense wavelength division demultiplexer 5 have a plurality of output ports, and idler photons of different frequency modes are output at different output ports through a filtering process; for example, the bandwidth of each frequency domain mode is 6.5GHz and the spacing between modes is 12.5 GHz.
The optical fiber coupler 4 is used for enabling the frequency domain broadband idler photons output by the frequency domain broadband entanglement light source 2 and the frequency domain broadband idler photons output by the frequency domain broadband entanglement light source 6 to generate two-photon interference.
n pairs of single photon detectors 81, 91, 82, 92.. 8n and 9n, wherein n is a positive integer and is used for detecting input photons and outputting electric pulse signals; the n coincidence logic circuits 101 and 102 … 10n have input channels with 2 or more independent signals, and are used for performing analog-to-digital conversion, delay and logic operation on input electric pulses, completing Bell state measurement, generating and outputting entanglement declaration signals, and two output ends of each coincidence logic circuit output the same entanglement declaration signals. When any one of the n coincidence logic circuits outputs an entanglement declaration signal, the quantum state of the two-photon output from the optical fiber coupler 4 is an entangled two-photon state, and this process can establish quantum entanglement between the first multi-channel quantum memory 1 and the first multi-channel quantum memory 7 at a high rate according to the entanglement swapping principle.
The photons coherently stored in the first multi-channel quantum memory 1 and the first multi-channel quantum memory 7 can be released in set storage time, the first multi-channel quantum memory 1 and the first multi-channel quantum memory 7 can shift the frequency of the released photons according to the entanglement announcement signal and output the shifted photons, the output photons have the same frequency, and the process can enable the first multi-channel quantum memory 1 and the first multi-channel quantum memory 7 to output the frequency identical entangled photon pairs at a high speed.
Alternatively, as shown in fig. 2, the first multi-channel quantum memory 1 and the second multi-channel quantum memory 7 have the same structure, and include a first laser source 11, a first phase modulator 12, an intensity modulator 13, a circulator 14, an erbium-doped optical waveguide 15 at the temperature of a refrigerator, a dense wavelength division multiplexer 16, a third dense wavelength division demultiplexer 26, a second phase modulator 17, and a frequency-shift electrical signal generation module 18;
the first laser source 11 is connected with a first port of the circulator 14 through the first phase modulator 12 and the intensity modulator 13 in sequence, and the frequency domain broadband signal photon omegasOutputting signal photons omega of n frequency modes via a third dense wavelength-division demultiplexer 26s1、ωs2…ωsnSignal photons ω of n frequency modess1、ωs2…ωsnThe frequency domain multimode signal photons are output by a dense wavelength division multiplexer 16, the frequency domain multimode signal photons are connected with a second port of a circulator 14 through an erbium-doped optical waveguide 15 at the temperature of a refrigerator, a third port of the circulator 14 is connected with an optical input end of a second phase modulator 17, an entanglement announcement signal is connected with an electrical signal input end of the second phase modulator 17 through a frequency shift electrical signal generation module 18, and an output end of the second phase modulator 17 is used for outputting frequency homophotons.
In the above embodiment, the first laser source 11 is used to provide stable laser light, and the first phase modulator 12 is used to shift the frequency of the laser light output by the first laser source 11. Specifically, under the action of the externally modulated electrical signal, the refractive index of the electro-optical crystal in the first phase modulator 12 changes accordingly, so as to generate a time-varying additional phase, thereby realizing the frequency shift of the laser. The intensity modulator 13 modulates the intensity of the laser light output from the first laser light source 11 to generate pulsed laser light.
The circulator 14 has three ports, and light is input from the first port and emitted from the second port, light is input from the second port and emitted from the third port, pulse laser light output from the intensity modulator 13 is input to the first port and output from the second port and injected into the erbium-doped optical waveguide at the refrigerator temperature, and photons output from the third port and enter the phase modulator 17 when photons output from the erbium-doped optical waveguide at the refrigerator temperature are injected into the second port.
The erbium doped optical waveguide 15 at the temperature of the refrigerator provides a storage medium for the multi-channel quantum memory. When light at the second port of the circulator 14 is injected into the erbium-doped optical waveguide, an atomic frequency comb can be prepared in the erbium-doped optical waveguide in a magnetic field environment at the temperature of the refrigerator, and the atomic frequency comb can realize coherent storage on input frequency-domain multimode signal photons and release the photons in a set storage time. The basic principle for preparing the atomic frequency comb is as follows: at the temperature of the refrigerator, light injected into the erbium-doped optical waveguide from the second port of the circulator 14 can perform frequency-domain periodic persistent hole burning on the absorption spectrum which is unevenly broadened by the erbium ion ensemble, so that a series of absorption peaks with frequency-domain periodic intervals of delta are obtained on the absorption spectrum of the erbium ion ensemble, and the absorption peaks form an atomic frequency comb. The principle that the atomic frequency comb realizes coherent storage and release on input frequency domain multimode signal photons is as follows: the incident frequency domain multimode signal photons are absorbed by the atomic frequency comb, so that erbium ions in the atomic frequency comb are all in coherent superposition states of a ground state and an excited state, namely alpha | g + beta eiΩt| e >, wherein α and β are superposition coefficients, and | α |, > is satisfied2+|β|21, Ω is a coefficient of linear variation of the phase of the excited state in the coherent superposition state with time t. Because the erbium ions in different comb teeth have different omega, after the frequency domain multimode signal photon is absorbed, the macroscopic polarization generated in the atomic frequency comb can be quickly weakened, the atomic frequency comb can not release the photon to the outside, and the excited states in the coherent superposition states of the erbium ions in different comb teeth can obtain the same phase until t is 2 pi/delta. At this time, the atomic frequency comb will generate strong macroscopic polarization again, and release multimode signal photons to the outside. The storage time can be set by setting Δ.
For example, at a refrigerator temperature of 9.5mK, a fiber coupled continuous laser with a center wavelength of 1532nm is used as the first laser source 11, a phase modulator using lithium niobate as an electro-optical crystal is used as the first phase modulator, and a chirp signal is applied to the first phase modulator, whereby a frequency shift of the incident laser light in the range of 1GHz to 5GHz can be realized. An acousto-optic modulator with the working wavelength range of 1520 nm-1580 nm, the extinction ratio of 60dB and the insertion loss of 3dB is used as an intensity modulator, and incident laser can be modulated into pulse light with the pulse width of 500ms and the repetition period of 10 s. An optical fiber circulator is used as the circulator 14, the working wavelength of the optical fiber circulator is 1532nm, the isolation is greater than 40dB, the insertion loss is 1dB, the return loss is greater than 50dB, output light of the second port of the circulator enters erbium-doped optical fiber (the erbium ion doping concentration is 200ppm) in a 180G magnetic field environment, and an atomic frequency comb with the comb tooth interval of 200MHz, the comb tooth width of 100MHz and the total bandwidth of 5GHz can be prepared, as shown in FIG. 4. In fig. 4, the abscissa represents the detuning amount of the absorption frequency of the erbium ion in the atomic frequency comb with respect to the output laser frequency of the first laser source 11, and the ordinate represents the optical thickness of the atomic frequency comb. The atomic frequency comb can realize coherent storage with the storage time of 5ns for incident frequency-domain multimode signal photons.
The third dense wavelength division demultiplexer 26 has a plurality of output ports, and outputs signal photons of different frequency modes at different output ports through a filtering process; for example, the bandwidth of each frequency domain mode is 6.5GHz, and the spacing between the modes is 12.5 GHz; the dense wavelength division multiplexer 16 has a plurality of input ports, and signal photons of different frequency modes are input to different input ports, and a path of frequency domain multimode signal photons is output through a wavelength division multiplexing process.
The frequency shift electric signal generating module in the first and second multi-channel quantum memories generates frequency shift electric signals with different frequency shift amounts according to the channel number Hi (i ═ 1,2, … … n) of the input entanglement declaration signal, the electric signals are input to the second phase modulators 17 in the first and second multi-channel quantum memories, and the second phase modulators perform frequency shift on the input photons according to the frequency shift electric signals, so that the photons output by the second phase modulators have the same property in the frequency domain, namely, the photons with the same frequency are output. For example, the frequency shift electrical signal is a chirp signal, chirp signals with different slopes are generated according to the channel number of the entanglement announcement signal, and the chirp signals with different slopes have different corresponding frequency shift amounts, so that photons with different frequency modes input in the second phase modulator experience frequency shift with different frequency shift amounts and become frequency identical photons.
Alternatively, as shown in fig. 3, the first frequency domain broadband entangled-light source 2 and the second frequency domain broadband entangled-light source 6 have the same structure, and include a second laser source 19, an optical amplifier 20, a polarization controller 21, a tunable optical attenuator 22, a band-pass filter 27, a nonlinear optical medium 23, a notch filter 24, and a wavelength selection device 25;
the second laser source 19 is connected with the input end of a wavelength selection device 25 through an optical amplifier 20, a polarization controller 21, an adjustable optical attenuator 22, a band-pass filter 27, a nonlinear optical medium 23 and a notch filter 24 in sequence, and the wavelength selection device 25 respectively outputs frequency domain broadband idler photons omegaiSum frequency domain broadband signal photons omegas。
In the above embodiment, the second laser source 19 is used to provide stable pump light, such as a fiber coupled semiconductor laser, providing pump light with a center wavelength of 1500nm to 1570 nm.
The optical amplifier 20 is used for amplifying the pump light to realize the function of improving the power of the pump light, and the working wavelength range is 1528nm to 1566 nm. For example, the continuous pump light with the center wavelength of 1540nm and the average power of 0.92mW is boosted to 4.5mW after passing through the optical amplifier.
The polarization controller 21 is configured to manipulate the polarization direction of the pump light to ensure that the pump light entering the nonlinear optical medium 23 is linearly polarized light parallel to the polarization main axis of the nonlinear optical medium. The polarization direction of the direct current pump light is adjusted to be parallel to the polarization main axis of the periodically polarized lithium niobate crystal, for example, by using a polarization controller.
The adjustable optical attenuator 22 is used to adjust the power of the dc laser entering the nonlinear optical medium 23, and the required pump light power can be precisely achieved by adjusting a knob or the like. For example, the direct current laser outputs 4.5mW power after passing through the erbium-doped fiber amplifier, and the power of the laser entering the periodically poled lithium niobate crystal is reduced to 3.73mW by adjusting the attenuator.
The band-pass filter (27) is used for filtering amplified spontaneous emission noise generated in the optical amplifier and spontaneous Raman scattering noise generated in the process of propagating the pump light.
The nonlinear optical medium 23 is used to produce an optical nonlinear parametric process that generates broadband entangled photon pairs. For example, the nonlinear optical medium is a periodically polarized lithium niobate crystal, and when continuous pump light with a central wavelength of 1540nm enters along the polarization main axis of the periodically polarized lithium niobate crystal, the optical frequency doubling process in the crystal converts the 1540nm pump light into laser with a wavelength of 770nm, and the 770nm laser generates energy-time entangled photon pairs which are distributed in a wide bandwidth range and have a wavelength of 1540nm as the center through a 0-type spontaneous parametric down-conversion process.
The notch filter 24 is used to filter the pump light, for example, a single-channel dense wavelength division demultiplexer with a center wavelength of a transmission end being 1540nm is used as the notch filter, the pump light with a wavelength of 1540nm can be output from the transmission end of the notch filter, and the entangled photon pair is output from the reflection end of the notch filter, i.e., the pump light is filtered.
The wavelength selection device 25 is used to select, separate and output the frequency domain broadband signal photons and the frequency domain broadband idler photons of the associated photon pair. For example, using a dual-channel dense wavelength division demultiplexer with a transmission end center wavelength at 1549nm and 1531nm and a channel bandwidth of 100GHz as the wavelength selection device, signal photons and idler photons with a transmission end center wavelength at 1549nm and 1531nm and a bandwidth of 100GHz can be respectively selected and output from the two transmission ends.
Optionally, the single photon detector is a semiconductor avalanche detector or a superconducting nanowire single photon detector.
In the above embodiment, the single photon detector may also be a single photon detector based on a frequency up-conversion technology.
Optionally, the laser source is a solid state laser, a gas laser, a semiconductor laser, or a dye laser.
Optionally, the phase modulator is a phase modulator with KDP crystal or lithium niobate crystal as an electro-optical crystal.
Optionally, the erbium-doped optical waveguide 15 at the refrigerator temperature is an erbium-doped lithium niobate crystal waveguide, an erbium-doped optical fiber or an erbium-doped yttrium silicate crystal waveguide.
Optionally, the polarization controller 21 is a slide type polarization controller or a fiber ring type polarization controller.
Optionally, the nonlinear optical medium 23 is a periodically poled lithium niobate crystal, a periodically poled potassium titanyl phosphate crystal, or a periodically poled barium metaborate crystal.
Optionally, the intensity modulator 13 is an intensity modulator based on acousto-optic or electro-optic effects.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. A frequency domain multiplexing quantum channel basic link of an optical fiber communication waveband is characterized by comprising a first multi-channel quantum memory (1), a second multi-channel quantum memory (7), a first frequency domain broadband entanglement light source (2), a second frequency domain broadband entanglement light source (6) and a multi-channel Bell state measuring device; the multi-channel Bell state measuring device comprises a first dense wavelength division demultiplexer (3), a second dense wavelength division demultiplexer (5), a fiber coupler (4), n pairs of single photon detectors (81, 91, 82, 92.. 8n, 9n, n is a positive integer) and n coincidence logic circuits (101, 102 … 10 n);
the frequency domain broadband idler photons (omega) generated by the first frequency domain broadband entanglement light source (2) and the second frequency domain broadband entanglement light source (6)i) The photons enter the optical fiber coupler (4) through the optical fiber to generate two-photon interference, and the first path of photons output by the optical fiber coupler (4) enters the second dense wavelength division demultiplexer (5) through the optical fiber to output first idler photons (omega) with n frequency modesi11…ωi1n) After the second path of photons output by the optical fiber coupler (4) enters the first dense wavelength division demultiplexer (3) through the optical fiber, second idler photons (omega) of n frequency modes are outputi21…ωi2n) The first idler photons of n frequency modes are respectively detected by n single-photon detectors, the second idler photons of n frequency modes are respectively detected by another n single-photon detectors, after the first idler photons and the second idler photons of the same frequency mode are respectively detected by a pair of single-photon detectors, the generated electric pulse signals enter corresponding coincidence logic circuits, the coincidence logic circuits carry out analog-to-digital conversion, delay and logic operation on the input electric pulse signals to complete Bell state measurement, an entanglement announcement signal is output, and the entanglement announcement signal enters a first multi-channel quantum memory (1) and a second multi-channel quantum memory (7);
the frequency domain broadband signal photons (omega) generated by the first frequency domain broadband entanglement light source (2) and the second frequency domain broadband entanglement light source (6)s) Respectively entering a first multi-channel quantum memory (1) and a second multi-channel quantum memory (7), wherein the first multi-channel quantum memory (1) and the second multi-channel quantum memory (7) generate and output entangled photon pairs with identical frequencies according to input entangled announcement signals;
the first multi-channel quantum memory (1) and the second multi-channel quantum memory (7) have the same structure and comprise a first laser source (11), a first phase modulator (12), an intensity modulator (13), a circulator (14), an erbium-doped optical waveguide (15) at the temperature of a refrigerator, a dense wavelength division multiplexer (16), a third dense wavelength division demultiplexer (26), a second phase modulator (17) and a frequency shift electric signal generating module (18);
the first laser source (11) is connected with a first port of the circulator (14) through a first phase modulator (12) and an intensity modulator (13) in sequence, and the frequency domain broadband signal photons (omega) ares) Outputting signal photons (ω) of n frequency modes via a third dense wavelength division demultiplexer (26)s1、ωs2…ωsn) Signal photons of n frequency modes (ω)s1、ωs2…ωsn) Frequency domain multimode signal photons are output through a dense wavelength division multiplexer (16), the frequency domain multimode signal photons are connected with a second port of a circulator (14) through an erbium-doped optical waveguide (15) at the temperature of a refrigerator, a third port of the circulator (14) is connected with an optical input end of a second phase modulator (17), an entanglement announcement signal is connected with an electrical signal input end of the second phase modulator (17) through a frequency shift electrical signal generating module (18), and an output end of the second phase modulator (17) is used for outputting frequency identical photons;
the first frequency domain broadband entangled light source (2) and the second frequency domain broadband entangled light source (6) are the same in structure and comprise a second laser source (19), an optical amplifier (20), a polarization controller (21), a variable optical attenuator (22), a band-pass filter (27), a nonlinear optical medium (23), a notch filter (24) and a wavelength selection device (25);
the second laser source (19) is connected with the input end of a wavelength selection device (25) through an optical amplifier (20), a polarization controller (21), a variable optical attenuator (22), a band-pass filter (27), a nonlinear optical medium (23) and a notch filter (24) in sequence, and the wavelength selection device (25) outputs frequency domain broadband idler photons (omega)i) And frequency domain broadband signal photons (ω)s)。
2. The frequency domain multiplexed quantum channel fundamental link of an optical fiber communication band of claim 1, wherein the single photon detector is a semiconductor avalanche detector or a superconducting nanowire single photon detector.
3. The frequency domain multiplexed quantum channel fundamental link of an optical fiber communication band as claimed in claim 1, wherein the laser source is a solid laser, a gas laser, a semiconductor laser or a dye laser.
4. The frequency domain multiplexed quantum channel fundamental link of a fiber optic communication band as claimed in claim 1, wherein said phase modulator is a phase modulator using KDP crystal or lithium niobate crystal as electro-optical crystal.
5. The frequency domain multiplexed quantum channel fundamental link of an optical fiber communication band according to claim 1, wherein the erbium-doped optical waveguide (15) at the refrigerator temperature is an erbium-doped lithium niobate crystal waveguide, an erbium-doped optical fiber or an erbium-doped yttrium silicate crystal waveguide.
6. The frequency domain multiplexed quantum channel base link of the optical fiber communication band of claim 1, wherein the polarization controller (21) is a glass-type polarization controller or a fiber ring-type polarization controller.
7. The frequency domain multiplexed quantum channel fundamental link of an optical fiber communication band according to claim 1, wherein the nonlinear optical medium (23) is a periodically poled lithium niobate crystal, a periodically poled titanyl potassium phosphate crystal, or a periodically poled barium metaborate crystal.
8. A frequency domain multiplexed quantum channel fundamental link in the optical fiber communication band according to claim 1, characterized in that the intensity modulator (13) is an intensity modulator based on acousto-optic or electro-optic effect.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101176297A (en) * | 2005-05-17 | 2008-05-07 | 朗迅科技公司 | Multi-channel transmission of quantum information |
| US9735890B2 (en) * | 2014-11-21 | 2017-08-15 | Vencore Labs, Inc. | Quantum communications of a two-qubit state |
| CN107113169A (en) * | 2015-01-09 | 2017-08-29 | 巴黎矿业电信学院 | Come from the communication with permanent security that short term security encrypts quantum communications |
| CN107979462A (en) * | 2017-12-29 | 2018-05-01 | 中南大学 | Quantum key dispatching system and its implementation based on Orthogonal Frequency Division Multiplexing |
| JP2018194518A (en) * | 2017-05-22 | 2018-12-06 | 国立研究開発法人産業技術総合研究所 | Frequency multiplexing read-out device and design method of the same |
| CN110247705A (en) * | 2019-06-21 | 2019-09-17 | 武汉邮电科学研究院有限公司 | A kind of light quantum converged network realization method and system based on multi-core optical fiber |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015017969A1 (en) * | 2013-08-05 | 2015-02-12 | 华为技术有限公司 | Bandwidth allocation method, device and system |
| CN104848880B (en) * | 2015-05-26 | 2017-03-08 | 电子科技大学 | A kind of quasi-distributed optical sensing devices based on photon technique |
-
2020
- 2020-03-13 CN CN202010173574.4A patent/CN111327369B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101176297A (en) * | 2005-05-17 | 2008-05-07 | 朗迅科技公司 | Multi-channel transmission of quantum information |
| US9735890B2 (en) * | 2014-11-21 | 2017-08-15 | Vencore Labs, Inc. | Quantum communications of a two-qubit state |
| CN107113169A (en) * | 2015-01-09 | 2017-08-29 | 巴黎矿业电信学院 | Come from the communication with permanent security that short term security encrypts quantum communications |
| JP2018194518A (en) * | 2017-05-22 | 2018-12-06 | 国立研究開発法人産業技術総合研究所 | Frequency multiplexing read-out device and design method of the same |
| CN107979462A (en) * | 2017-12-29 | 2018-05-01 | 中南大学 | Quantum key dispatching system and its implementation based on Orthogonal Frequency Division Multiplexing |
| CN110247705A (en) * | 2019-06-21 | 2019-09-17 | 武汉邮电科学研究院有限公司 | A kind of light quantum converged network realization method and system based on multi-core optical fiber |
Non-Patent Citations (2)
| Title |
|---|
| Quantum Entanglement Distribution Coexisting with Classical Fiber Communication;Chenzhi Yuan;《 2019 Asia Communications and Photonics Conference (ACP)》;20200210;全文 * |
| 纠缠度随相位阻尼和光频差变化规律的研究;邹世乾;《西南大学学报(自然科学版)》;20130720;全文 * |
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