Preparation device and method of a multi-channel broadband light-atom interface

Abstract

The present application relates to a kind of preparation device and method of multi-channel broadband light-atom interface, the present application is prepared in erbium-doped solid-state material by combining light frequency comb generation technology and frequency chirp control technology, and the quantum association or entanglement photon pair in the broadband multi-frequency multiplexing quantum association or entanglement photon pair of optical communication band broadband multi-channel broadband atomic frequency comb is stored in time domain multi-mode by multi-channel broadband atomic frequency comb, to establish the quantum association or entanglement between another photon and atomic frequency comb, form light-atom interface.The components for preparing multi-channel broadband light-atom interface of the present application can be from mature optoelectronic devices, which is beneficial to the development of practical quantum network node based on light-atom interface.The light-atom interface prepared by this method has the advantages of large bandwidth, multi-channel, etc., and can be widely used in the field of quantum communication, quantum entanglement network, etc.

Description

Technical Field

[0001] This invention belongs to the field of quantum information, specifically relating to a device and method for preparing optical-atomic interfaces in multi-channel broadband optical communication bands. Background Technology

[0002] A quantum network consists of local quantum nodes and quantum channels connecting them. The function of the local quantum nodes is to acquire, process, and transmit quantum information, while the function of the quantum channels is to connect these nodes. This connection can effectively realize information exchange between local quantum nodes, improving information processing capabilities. Therefore, constructing efficient and practical quantum channels is key to building a quantum network. As a common carrier of quantum information, photons suffer from signal attenuation with increasing distance in any transmission medium, limiting their propagation distance. An effective solution to this problem is to use quantum repeaters to achieve entanglement swapping of qubits between different nodes, thereby establishing a full-link entanglement and enabling interconnection of quantum nodes at arbitrary distances. A complete quantum repeater node needs to include basic components such as a quantum memory and a Bell state measurement device, with the quantum memory playing a crucial synchronization role in the entanglement swapping process.

[0003] As a crucial device for realizing quantum networks, quantum memories are based on the physical principle of the interaction between light and atoms. Atoms absorb photons to establish photoatomic interfaces, thus storing photonic quantum states. A key performance factor for quantum memories is their storage bandwidth; wider bandwidth is essential for improving network communication speed. Currently, commonly used physical systems for establishing photoatomic interfaces include single atoms, atomic ensembles, rare-earth-doped solid-state ensembles, NV / SiV color centers, quantum dots, and optomechanical oscillators. However, currently realized photoatomic interfaces suffer from limited channels and low storage bandwidth, restricting the communication speed of quantum networks. Therefore, there is an urgent need to develop a device for fabricating multi-channel, high-bandwidth photoatomic interfaces. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for realizing optical-atomic interfaces in multi-channel broadband optical communication bands, in response to the needs of existing technologies.

[0005] To address the aforementioned technical problems, this invention provides a multi-channel broadband optical communication band optical-atomic interface fabrication device, comprising a multi-channel broadband atomic frequency comb fabrication device and a multi-frequency mode multiplexed optical communication band quantum correlation source or quantum entanglement source, which are connected by an optical fiber.

[0006] The multi-channel broadband atomic frequency comb preparation device utilizes optical frequency comb generation technology and frequency chirp control technology to prepare multi-channel broadband atomic frequency combs in erbium-doped solid materials.

[0007] The multi-frequency mode multiplexed optical communication band quantum correlation source or quantum entanglement source generates multi-frequency mode multiplexed quantum correlation photon pairs or quantum entanglement photon pairs through a periodically polarized lithium niobate waveguide. The atomic frequency comb performs time-domain multimode storage on one photon of the quantum correlation photon pair or quantum entanglement photon pair, establishes quantum correlation or quantum entanglement between the other photon of the quantum correlation photon pair or quantum entanglement photon pair and the atomic frequency comb, and forms a multi-channel bandwidth optical communication band optical-atomic interface.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the multi-channel broadband atomic frequency comb fabrication device includes a first laser source 15, a first optical intensity modulator 16, a first optical phase modulator 17, a second optical phase modulator 18, an optical switch 19, and a first adjustable optical attenuator 20 connected in sequence. One end of the first adjustable optical attenuator 20 is connected to the optical switch 19, and the other end of the first adjustable optical attenuator 20 is connected to the first port of the optical circulator 21. The second port of the optical circulator 21 is connected to one end of the erbium-doped solid material 22.

[0010] The first laser source 15 is used to provide continuous and stable pump light;

[0011] The light intensity modulator 16 and the first light phase modulator 17 are used to modulate the pump light output from the first laser source 15 into an optical frequency comb with several comb teeth.

[0012] The second optical phase modulator 18 is used to load a periodic frequency shift signal onto the optical frequency comb. In each period, the comb teeth will be shifted several times at equal intervals. The interval after periodic frequency shift of each comb tooth is a frequency domain mode. An optical frequency comb with several similar comb teeth becomes a multi-mode pump light.

[0013] The first adjustable light attenuator 20 is used to adjust the power of the pump light.

[0014] Furthermore, the multi-frequency mode multiplexing quantum correlation source or quantum entanglement source includes a second laser source 1, a second optical intensity modulator 2, an optical amplifier 3, a second tunable optical attenuator 4, a polarization controller 5, a polarizer 6, a nonlinear crystal waveguide 7, and a first optical isolator 8 connected in sequence.

[0015] One end of the first optical isolator 8 is connected to the nonlinear crystal waveguide 7, and the other end of the first optical isolator 8 is connected to the common terminal (C terminal) of the first dense wavelength division multiplexer 9. The transmission terminal (T terminal) of the first dense wavelength division multiplexer 9 is connected to one end of the first optical filter 10. The reflection terminal (R terminal) of the first dense wavelength division multiplexer 9 is connected to the common terminal (C terminal) of the second dense wavelength division multiplexer 11. The transmission terminal (T terminal) of the second dense wavelength division multiplexer 11 is connected to the input terminal of the second optical filter 12. The N output terminals of the second optical filter 12 are connected to the N transmission terminals (T terminals) of the third dense wavelength division multiplexer 13, respectively. The common terminal (C terminal) of the third dense wavelength division multiplexer 13 is connected to one end of the second optical isolator 14, and the other end of the second optical isolator 14 is connected to one end of the erbium-doped solid material 22 in the multi-channel broadband atomic frequency comb preparation device.

[0016] Furthermore, the erbium-doped solid material 22 is an erbium-doped lithium niobate crystal, an erbium-doped yttrium silicate crystal, an erbium-doped quartz optical fiber, or an erbium-doped gadolinium vanadate crystal.

[0017] Furthermore, the first laser source 15 and the second laser source 1 are solid-state laser sources, gas laser sources, semiconductor laser sources or dye laser sources.

[0018] Furthermore, the first intensity modulator 16 and the second intensity modulator 2 are intensity modulators based on acousto-optic effect or electro-optic effect;

[0019] And / or, the first optical phase modulator 17 and the second optical phase modulator 18 are electro-optic phase modulators using KDP crystal or lithium niobate crystal as electro-optic crystals.

[0020] Furthermore, the first dense wavelength division multiplexer 9, the second dense wavelength division multiplexer 11, and the third dense wavelength division multiplexer 13 are thin-film dense wavelength division multiplexers, bulk grating dense wavelength division multiplexers, arrayed waveguide grating dense wavelength division multiplexers, or fiber grating dense wavelength division multiplexers.

[0021] Furthermore, the first optical filter 10 and the second optical filter 12 are fiber Bragg grating filters, cascaded fiber Bragg grating filters, or bulk grating filters.

[0022] And / or, the polarization controller 5 is a waveplate polarization controller or an optical fiber polarization controller.

[0023] To address the aforementioned technical problems, this invention provides a method for fabricating a multi-channel broadband optical communication band optical-atomic interface, which is implemented using the aforementioned fabrication apparatus for a multi-channel broadband optical communication band optical-atomic interface, and includes the following steps:

[0024] Multi-channel broadband atomic frequency combs were prepared in erbium-doped solid materials using optical frequency comb generation technology and frequency chirp modulation technology.

[0025] The atomic frequency comb performs time-domain multimode storage on one photon from a quantum-correlated photon pair or a quantum-entangled photon pair in a broadband multi-frequency mode multiplexed optical communication band, establishing a quantum correlation or quantum entanglement between the other photon in the quantum-correlated photon pair or the quantum-entangled photon pair and the atomic frequency comb, thus forming a multi-channel broadband optical communication band optical-atomic interface.

[0026] Furthermore, the preparation method of the atomic frequency comb specifically includes the following steps:

[0027] An optical frequency comb with several comb teeth is generated using optical frequency comb technology. The optical frequency comb is periodically shifted using frequency chirp control technology. The comb teeth are shifted several times at equal intervals within each period. The interval after periodic frequency shifting of each comb tooth is a frequency domain mode. The optical frequency comb with several similar comb teeth becomes a multimode pump light. The multimode pump light is used to pump erbium-doped solid materials. The pump light interacts with the erbium ion ensemble in the erbium-doped solid materials. The corresponding erbium ions in the erbium-doped solid materials are excited using the principle of spectral hole burning. The remaining ground-state erbium ions form a multi-channel atomic frequency comb.

[0028] The beneficial effects of this invention are as follows: This invention relates to a device for preparing a multi-channel broadband optical communication band optical-atomic interface. An optical frequency comb with several teeth is generated using optical frequency comb technology. Frequency chirp modulation technology causes the teeth of the optical frequency comb to undergo periodic frequency shifts. Within each period, the teeth are shifted several times, with the shift amount being one to several times a set value. Any tooth that has undergone periodic frequency shifts represents a frequency domain mode, and the optical frequency comb with several teeth becomes a multi-mode pump light. The multi-mode pump light generated after the above modulation is input into an erbium-doped solid material. The pump light interacts with the erbium ion ensemble in the erbium-doped solid material, and a multi-channel atomic frequency comb is prepared in the erbium-doped solid material using the principle of spectral hole burning. Because erbium ions have a broad absorption spectrum, atomic frequency combs can be prepared over a wide range. The atomic frequency comb interacts with idler photons, achieving storage and establishing quantum correlations / entanglements between signal photons of different frequency modes and the erbium ion ensemble, forming an optical-atomic interface.

[0029] This invention prepares optical-atomic interface components for optical communication bands, all of which can be derived from mature optoelectronic devices, facilitating the practical development of quantum nodes based on optical-atomic interfaces. The optical-atomic interface prepared by this method has advantages such as ease of implementation, large bandwidth, and multiple channels. The prepared rare-earth quantum memory can achieve large-bandwidth, multi-channel storage of entangled photons in the optical communication band, improving the transmission speed of quantum information and thus having beneficial effects. It can be widely used in quantum communication, quantum entanglement networks, and other fields. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a multi-channel broadband optical communication band optical-atomic interface preparation device according to an embodiment of the present invention;

[0031] Figure 2 The absorption spectrum of the atomic frequency comb of five channels in erbium-doped solid material 22 obtained by using a multi-channel broadband optical communication band optical-atomic interface preparation device according to an embodiment of the present invention is shown.

[0032] The attached diagram lists the components represented by each number as follows:

[0033] 1. Second laser source; 2. Second optical intensity modulator; 3. Optical amplifier; 4. Second tunable optical attenuator; 5. Polarization controller; 6. Polarizer; 7. Nonlinear crystal waveguide; 8. First optical isolator; 9. First dense wavelength division multiplexer; 10. First optical filter; 11. Second dense wavelength division multiplexer; 12. Second optical filter; 13. Third dense wavelength division multiplexer; 14. Second optical isolator; 15. First laser source; 16. First optical intensity modulator; 17. First optical phase modulator; 18. Second optical phase modulator; 19. Optical switch; 20. First tunable optical attenuator; 21. Optical circulator; 22. Erbium-doped solid material. Detailed Implementation

[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0035] like Figure 1 As shown, the first embodiment of the present invention provides a multi-channel broadband optical communication band optical-atomic interface preparation device, including a multi-channel broadband atomic frequency comb preparation device and a multi-frequency mode multiplexed optical communication band quantum correlation source or quantum entanglement source, which are connected by optical fiber.

[0036] The multi-channel broadband atomic frequency comb preparation device utilizes optical frequency comb generation technology and frequency chirp control technology to prepare multi-channel broadband atomic frequency combs in erbium-doped solid materials.

[0037] The multi-frequency mode multiplexed optical communication band quantum correlation source or quantum entanglement source generates multi-frequency mode multiplexed quantum correlation photon pairs or quantum entanglement photon pairs through a periodically polarized lithium niobate waveguide. The atomic frequency comb performs time-domain multimode storage on one photon of the quantum correlation photon pair or quantum entanglement photon pair, establishes quantum correlation or quantum entanglement between the other photon of the quantum correlation photon pair or quantum entanglement photon pair and the atomic frequency comb, and forms a multi-channel bandwidth optical communication band optical-atomic interface.

[0038] The above embodiments combine optical frequency combs and frequency chirp modulation techniques to simultaneously prepare multiple high-bandwidth atomic frequency combs in an erbium-doped solid material, and with multi-frequency mode multiplexing correlation / entanglement photon storage, realize a multi-channel optical-atomic interface.

[0039] In this embodiment, the multi-channel broadband atomic frequency comb fabrication device includes a first laser source 15, a first optical intensity modulator 16, a first optical phase modulator 17, a second optical phase modulator 18, an optical switch 19, and a first adjustable optical attenuator 20 connected in sequence. One end of the first adjustable optical attenuator 20 is connected to the optical switch 19, and the other end of the first adjustable optical attenuator 20 is connected to the first port of the optical circulator 21. The second port of the optical circulator 21 is connected to one end of the erbium-doped solid material 22.

[0040] The first laser source 15 is used to provide continuous and stable pump light;

[0041] The light intensity modulator 16 and the first light phase modulator 17 are used to modulate the pump light output from the first laser source 15 into an optical frequency comb with several comb teeth.

[0042] The second optical phase modulator 18 is used to load a periodic frequency shift signal onto the optical frequency comb. In each period, the comb teeth will be shifted several times at equal intervals. The interval after periodic frequency shift of each comb tooth is a frequency domain mode. An optical frequency comb with several similar comb teeth becomes a multi-mode pump light.

[0043] The first adjustable light attenuator 20 is used to adjust the power of the pump light.

[0044] The multi-frequency mode multiplexing quantum correlation source or quantum entanglement source includes a second laser source 1, a second optical intensity modulator 2, an optical amplifier 3, a second adjustable optical attenuator 4, a polarization controller 5, a polarizer 6, a nonlinear crystal waveguide 7, and a first optical isolator 8 connected in sequence.

[0045] One end of the first optical isolator 8 is connected to the nonlinear crystal waveguide 7, and the other end of the first optical isolator 8 is connected to the common terminal (C terminal) of the first dense wavelength division multiplexer 9. The transmission terminal (T terminal) of the first dense wavelength division multiplexer 9 is connected to one end of the first optical filter 10. The reflection terminal (R terminal) of the first dense wavelength division multiplexer 9 is connected to the common terminal (C terminal) of the second dense wavelength division multiplexer 11. The transmission terminal (T terminal) of the second dense wavelength division multiplexer 11 is connected to the input terminal of the second optical filter 12. The N output terminals of the second optical filter 12 are connected to the N transmission terminals (T terminals) of the third dense wavelength division multiplexer 13, respectively. The common terminal (C terminal) of the third dense wavelength division multiplexer 13 is connected to one end of the second optical isolator 14, and the other end of the second optical isolator 14 is connected to one end of the erbium-doped solid material 22 in the multi-channel broadband atomic frequency comb preparation device.

[0046] The first laser source 15 outputs narrow-linewidth continuous pump light with a center wavelength of 1531.88nm, and the first laser source 15 is an external cavity semiconductor laser.

[0047] The narrow-linewidth continuous pump light output from the first laser source 15 is input to the first optical intensity modulator 16 and modulated into pulsed light. The first optical intensity modulator 16 is a lithium niobate electro-optical intensity modulator.

[0048] The pulsed light output from the first optical intensity modulator 16 is input to the first optical phase modulator 17. The first optical phase modulator converts the input pulsed light into an optical frequency comb with a center wavelength of 1531.88nm, a comb tooth spacing of 15GHz, and a comb tooth number of 5, based on the 15GHz microwave and electro-optic phase modulation principle loaded on it.

[0049] The optical frequency comb output from the first optical phase modulator 17 is input to the second optical phase modulator 18. According to the principle of electro-optic phase modulation, a sweep microwave signal with a sweep frequency range of 0-5GHz, a sweep frequency interval of 50MHz, and a sweep frequency period of 10 microseconds is loaded onto the second optical phase modulator 18 to periodically shift the input optical frequency comb. In each cycle, the optical frequency comb range is realized from -5GHz to 5GHz with an interval of 50MHz. The first optical phase modulator 17 and the second optical phase modulator 18 are lithium niobate electro-optic phase modulators.

[0050] The optical switch 19 employs a 1×2 MEMS fiber optic switch to control the on / off state of the pump light used to prepare the atomic frequency comb. It remains "on" before the multiplexed idler photons enter the erbium-doped solid material 22, and remains "off" when the idler photons enter the erbium-doped solid material 22. In this embodiment, the optical frequency comb output from the second optical phase modulator 18 is input to the optical switch 19. The optical switch operates in an "on" or "off" state according to the electrical signal applied to it. In the "on" state, the optical frequency comb input to the optical switch 19 is output from its output terminal; in the "off" state, the optical frequency comb input to the optical switch 19 is not output from its output terminal. Within a 1-second period, the optical switch remains in the "on" state for 300ms, and remains in the "off" state for the rest of the time.

[0051] The second intensity modulator 2 modulates the narrow-linewidth continuous laser output from the second laser source 1 into pulsed pump light. In this embodiment, the second laser source 1 outputs a continuous pump laser with a center wavelength of 1540.60 nm. The continuous pump laser output from the second laser source 1 is input into the second intensity modulator 2, which modulates the continuous pump laser into a pulsed pump laser with a pulse width of 300 ps. The second laser source 1 is an external cavity semiconductor laser, and the second intensity modulator 2 is a lithium niobate electro-optic intensity modulator.

[0052] The optical amplifier 3 and the second adjustable optical attenuator 4 enable the adjustment of pump light power. In this embodiment, the pulsed pump laser output from the second intensity modulator 2 is input to the second optical amplifier 3, and the second optical amplifier 3 amplifies the power of the input pulsed pump laser.

[0053] The pulsed pump laser output from the second optical amplifier 3 is input to the second optical attenuator 4 to achieve power control of the pulsed pump laser. The average optical power of the pulsed pump laser output from the optical attenuator 4 is 0.49mW. The optical amplifier 3 is an erbium-doped fiber amplifier, and the second adjustable optical attenuator 4 is an adjustable fiber attenuator.

[0054] The pulse pump laser output from the second optical attenuator 4 is input to the polarization controller 5, thereby achieving polarization control of the pulse pump laser.

[0055] The pulsed pump laser output from polarization controller 5 is input to polarizer 6, and the pulsed pump laser output from polarizer 6 is linearly polarized light. By changing the operating state of polarization controller 5, the power of the pulsed pump laser output from polarizer 6 can be maximized. The polarization controller 5 is a fiber polarization controller, and the polarizer 6 is a fiber polarizer.

[0056] Under the action of pump light, the nonlinear crystal waveguide (7) undergoes a spontaneous parametric down-conversion process, generating a bandwidth covering wavelength λ. s1 , λ s2 ……λsn Broadband signal photons and bandwidth covering wavelength λ i1 , λ i2 ……λ in Broadband idler photons with wavelength λ sk Signal photons (k = 1, 2, ..., n) and wavelength λ ik There are quantum correlations or quantum entanglements among the idler photons (k = 1, 2, ..., n). In this embodiment, the linearly polarized pulsed pump laser output from polarizer 6 is input to nonlinear crystal waveguide 7, which is a periodically polarized lithium niobate waveguide. In nonlinear crystal waveguide 7, the pulsed pump laser with a center wavelength of 1540.60 nm first generates a pulsed pump laser with a center wavelength of 770.30 nm through a second harmonic generation process. The latter generates photon pairs with a center wavelength of 1540.60 nm and a spectral width greater than 60 nm through spontaneous parametric down-conversion. In each photon pair, one photon is the signal photon and the other is the idler photon. According to the principle of spontaneous parametric down-conversion, there is a quantum correlation between the signal photon and the idler photon.

[0057] Quantum correlated / entangled photon pairs generated in the nonlinear crystal waveguide 7 are output from it and then input to the second optical isolator 8; the quantum correlated / entangled photon pairs output from the second optical isolator 8 are input to the common terminal (C terminal) of the first dense wavelength division multiplexer 9.

[0058] The first dense wavelength division multiplexer 9 and the second dense wavelength division multiplexer 11 are used to filter out broadband signal photons and idler photons, respectively; the k-th (k=1、……N) port of the first optical filter 10 out of N (N≤n) output ports is used to output the center wavelength λ. sk The signal photons output from the N output ports do not have spectral overlap; in this embodiment, the transmission end (T end) of the first dense wavelength division multiplexer 9 outputs signal photons with a center wavelength of 1549nm and a bandwidth of 100GHz, and the reflection end (R end) outputs photons with wavelengths outside the transmission wavelength range of the transmission end.

[0059] The signal photons output from the transmission end of the first dense wavelength division multiplexer 9 are input to the first optical filter 10. The five output ends of the first optical filter 10 output signal photons of five frequency modes respectively. Each frequency mode has a bandwidth of 10 GHz and the center frequency interval between adjacent frequency modes is 15 GHz.

[0060] The photons output from the reflection end (R end) of the first dense wavelength division multiplexer 9 are input to the second dense wavelength division multiplexer 11. The transmission end (T end) of the second dense wavelength division multiplexer 11 outputs idler photons with a center wavelength of 1532nm and a bandwidth of 100GHz. The idler photons output from the transmission end (T end) of the second dense wavelength division multiplexer 11 are input to the second optical filter 12.

[0061] The k-th (k = 1, 2, ..., n) port of the second optical filter (12) is used to output a center wavelength of λ. ik The idler photons output from the N output ports do not have spectral overlap. In this embodiment, the five output ports of the second optical filter 12 output idler photons of five frequency modes, each frequency mode having a bandwidth of 10 GHz and a center frequency interval of 15 GHz between adjacent frequency modes. The signal photon output from the j-th (j = 1, 2, ... 5) output port of the first optical filter 10 and the idler photon output from the j-th (j = 1, 2, ... 5) output port of the second optical filter 12 constitute a quantum correlated / entangled photon pair.

[0062] The transmission center wavelength of the kth (k = 1, 2, ..., N)th transmission terminal (T terminal) of the third dense wavelength division multiplexer (13) is λ. ik (k = 1, ..., N), to realize the multiplexing of multiplexed photons of the idler modes input by N transmission ends (T ends); in this embodiment, the idler photons of the five frequency modes output by the second optical filter 12 are input to the five transmission ends (T ends) of the third dense wavelength division multiplexer 13, and all of them are emitted from the common end (C end) of the third dense wavelength division multiplexer 13, thereby realizing the multiplexing of the idler photons of the five frequency modes.

[0063] The second optical isolator 14 is used to block the pump light of the atomic frequency comb prepared in the erbium-doped solid material 22 from entering the communication band quantum correlation source or quantum entanglement source of the broadband multi-frequency mode multiplexing.

[0064] The first optical isolator 8 and the second optical isolator 14 are fiber optic isolators. The first dense wavelength division multiplexer 9, the second dense wavelength division multiplexer 11 and the third dense wavelength division multiplexer 13 are diaphragm-type dense wavelength division multiplexers. The first optical filter 10 and the second optical filter 12 are five-stage cascaded fiber Bragg gratings.

[0065] The optical frequency comb output from the optical switch 19 enters the first optical attenuator 20 to achieve power regulation. The optical frequency comb output from the first optical attenuator 20 is incident on the first port of the optical circulator 21, exits from the second port of the optical circulator 21, and then incident on the erbium-doped solid material 22. The optical frequency comb, acting as pump light, interacts with the erbium ion ensemble in the erbium-doped solid material 22, exciting the corresponding erbium ions. The remaining ground-state erbium ions form an atomic frequency comb with five frequency domain modes. Each frequency comb has a frequency domain bandwidth of 10 GHz, the comb tooth spacing of each mode is 50 MHz, and the interval between adjacent frequency modes is 5 GHz. Figure 2 The absorption spectra of the atomic frequency combs of five channels in the experimentally measured erbium-doped solid material 22 are obtained from... Figure 2As can be seen, the mode bandwidth of each atomic frequency comb is 10 GHz, and the width between adjacent comb teeth within the mode is 50 MHz;

[0066] The idler photons of the five frequency modes output from the second optical filter 12 are input to the five transmission ends (T ends) of the third dense wavelength division multiplexer 13, and all exit from the common end (C end) of the third dense wavelength division multiplexer 13. The multi-frequency mode multiplexed idler photons output from the common end (C end) of the third dense wavelength division multiplexer 13 enter the erbium-doped solid material 22 through the second optical isolator 14 and are coherently stored in the multi-channel atomic frequency comb. Since there is a quantum correlation or quantum entanglement between the signal photons output from the kth (k=1, ..., N) output port of the first optical filter 10 and the idler photons input to the kth (k=1, ..., N) transmission end (T end) of the third dense wavelength division multiplexer 13 and output from its common end (C end), and the process of storing the idler photons in the atomic frequency comb is a coherent interaction, there is a quantum correlation or entanglement between the multi-channel atomic frequency comb storing the multi-frequency mode multiplexed idler photons and the multi-channel signal photons, that is, a multi-channel broadband optical-atomic interface is realized.

[0067] In the example:

[0068] 1.15: The laser source is an external cavity semiconductor laser.

[0069] 2.16: The intensity modulator is a lithium niobate electro-optic intensity modulator.

[0070] 3: The optical amplifier is an erbium-doped fiber amplifier.

[0071] 4.20: The adjustable attenuator is an adjustable fiber optic attenuator.

[0072] 5: The polarization controller is a fiber optic polarization controller.

[0073] 6: The polarizer is a fiber optic polarizer.

[0074] 7: The nonlinear crystal waveguide is a periodically polarized lithium niobate waveguide.

[0075] 8, 14: Optical isolators are fiber optic isolators.

[0076] 9, 11, 13: The dense wavelength division multiplexer is a diaphragm-type dense wavelength division multiplexer.

[0077] 10, 12: The optical filters are five-stage cascaded fiber Bragg gratings.

[0078] 17, 18: The phase modulator is a lithium niobate electro-optic phase modulator.

[0079] 19: The optical switch is a 1×2 MEMS fiber optic switch.

[0080] 21: The optical circulator is a fiber optic circulator.

[0081] 22: The erbium-doped solid material is an erbium-doped optical fiber located at a temperature of 10 mK and a magnetic field of 0.3 T.

[0082] Optionally, the erbium-doped solid material 22 is an erbium-doped lithium niobate crystal, an erbium-doped yttrium silicate crystal, an erbium-doped silica optical fiber, or an erbium-doped gadolinium vanadate crystal.

[0083] Optionally, the first laser source 15 and the second laser source 1 are solid-state laser sources, gas laser sources, semiconductor laser sources or dye laser sources.

[0084] Optionally, the first intensity modulator 16 and the second intensity modulator 2 are intensity modulators based on acousto-optic effect or electro-optic effect;

[0085] And / or, the first optical phase modulator 17 and the second optical phase modulator 18 are electro-optic phase modulators using KDP crystal or lithium niobate crystal as electro-optic crystals.

[0086] Optionally, the first dense wavelength division multiplexer 9, the second dense wavelength division multiplexer 11, and the third dense wavelength division multiplexer 13 can be thin-film dense wavelength division multiplexers, bulk grating dense wavelength division multiplexers, arrayed waveguide grating dense wavelength division multiplexers, or fiber grating dense wavelength division multiplexers.

[0087] Optionally, the first optical filter 10 and the second optical filter 12 are fiber Bragg grating filters, cascaded fiber Bragg grating filters, or bulk grating filters.

[0088] And / or, the polarization controller 5 is a waveplate polarization controller or an optical fiber polarization controller.

[0089] This invention combines optical frequency comb generation technology with frequency chirp manipulation technology to fabricate a multi-channel broadband atomic frequency comb in erbium-doped solid materials. The multi-channel broadband atomic frequency comb is then used to perform time-domain multimode storage of one photon in a quantum-correlated or entangled photon pair used for broadband multi-frequency multiplexing in the optical communication band, thereby establishing a quantum correlation or entanglement between the other photon and the atomic frequency comb, forming an optical-atomic interface. All components used in this invention to fabricate the multi-channel broadband optical-atomic interface can be derived from mature optoelectronic devices, which is beneficial for developing practical quantum network nodes based on optical-atomic interfaces. The optical-atomic interface fabricated by this method has advantages such as large bandwidth and multiple channels, and can be widely used in quantum communication, quantum entangled networks, and other fields.

[0090] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for preparing an optical-atomic interface in a multi-channel broadband optical communication band, characterized in that, It includes a multi-channel broadband atomic frequency comb preparation device and a multi-frequency mode multiplexed optical communication band quantum correlation source or quantum entanglement source, which are connected by optical fiber; The multi-channel broadband atomic frequency comb preparation device utilizes optical frequency comb generation technology and frequency chirp control technology to prepare multi-channel broadband atomic frequency combs in erbium-doped solid materials. The multi-frequency mode multiplexed optical communication band quantum correlation source or quantum entanglement source generates multi-frequency mode multiplexed quantum correlation photon pairs or quantum entanglement photon pairs through a periodically polarized lithium niobate waveguide. The atomic frequency comb performs time-domain multimode storage on one photon of the quantum correlation photon pair or quantum entanglement photon pair, establishes quantum correlation or quantum entanglement between the other photon of the quantum correlation photon pair or quantum entanglement photon pair and the atomic frequency comb, and forms a multi-channel bandwidth optical communication band optical-atomic interface. The multi-channel broadband atomic frequency comb fabrication device includes a first laser source (15), a first optical intensity modulator (16), a first optical phase modulator (17), a second optical phase modulator (18), an optical switch (19), and a first adjustable optical attenuator (20) connected in sequence. One end of the first adjustable optical attenuator (20) is connected to the optical switch (19), and the other end of the first adjustable optical attenuator (20) is connected to the first port of the optical circulator (21). The second port of the optical circulator (21) is connected to one end of the erbium-doped solid material (22). The multi-frequency mode multiplexing quantum correlation source or quantum entanglement source includes a second laser source (1), a second light intensity modulator (2), an optical amplifier (3), a second adjustable optical attenuator (4), a polarization controller (5), a polarizer (6), a nonlinear crystal waveguide (7), and a first optical isolator (8) connected in sequence.

2. The apparatus for preparing a multi-channel broadband optical communication band optical-atomic interface according to claim 1, characterized in that, The first laser source (15) is used to provide continuous and stable pump light; the light intensity modulator (16) and the first light phase modulator (17) are used to modulate the pump light output by the first laser source (15) into an optical frequency comb with several comb teeth; the second light phase modulator (18) is used to load a periodic frequency shift signal onto the optical frequency comb. In each period, the comb teeth will be shifted several times at equal intervals. The interval after periodic frequency shift of each comb tooth is a frequency domain mode. The optical frequency comb with several similar comb teeth becomes a multi-mode pump light. The first adjustable light attenuator (20) is used to adjust the power of the pump light.

3. The apparatus for preparing a multi-channel broadband optical communication band optical-atomic interface according to claim 1, characterized in that, One end of the first optical isolator (8) is connected to the nonlinear crystal waveguide (7), and the other end of the first optical isolator (8) is connected to the common terminal C of the first dense wavelength division multiplexer (9). The transmission terminal T of the first dense wavelength division multiplexer (9) is connected to one end of the first optical filter (10). The reflection terminal R of the first dense wavelength division multiplexer (9) is connected to the common terminal C of the second dense wavelength division multiplexer (11). The transmission terminal T of the second dense wavelength division multiplexer (11) is connected to the input terminal of the second optical filter (12). The second optical filter (12) N The output terminals and the third dense wavelength division multiplexer (13) N The transmission ends T are connected to each other, the common end C of the third dense wavelength division multiplexer (13) is connected to one end of the second optical isolator (14), and the other end of the second optical isolator (14) is connected to one end of the erbium-doped solid material (22) in the multi-channel broadband atomic frequency comb preparation device.

4. The apparatus for preparing a multi-channel broadband optical communication band optical-atomic interface according to claim 3, characterized in that, The erbium-doped solid material (22) is an erbium-doped lithium niobate crystal, an erbium-doped yttrium silicate crystal, an erbium-doped quartz optical fiber, or an erbium-doped gadolinium vanadate crystal.

5. The apparatus for preparing a multi-channel broadband optical communication band optical-atomic interface according to claim 3, characterized in that, The first laser source (15) and the second laser source (1) are solid-state laser sources, gas laser sources, semiconductor laser sources or dye laser sources.

6. The apparatus for preparing a multi-channel broadband optical communication band optical-atomic interface according to any one of claims 1-3, characterized in that, The first light intensity modulator (16) and the second light intensity modulator (2) are intensity modulators based on acousto-optic effect or electro-optic effect; And / or, the first optical phase modulator (17) and the second optical phase modulator (18) are electro-optic phase modulators using KDP crystal or lithium niobate crystal as electro-optic crystals.

7. The apparatus for preparing a multi-channel broadband optical communication band optical-atomic interface according to claim 3, characterized in that, The first dense wavelength division multiplexer (9), the second dense wavelength division multiplexer (11), and the third dense wavelength division multiplexer (13) are thin-film dense wavelength division multiplexers, bulk grating dense wavelength division multiplexers, arrayed waveguide grating dense wavelength division multiplexers, or fiber grating dense wavelength division multiplexers.

8. The apparatus for preparing a multi-channel broadband optical communication band optical-atomic interface according to claim 3, characterized in that, The first optical filter (10) and the second optical filter (12) are fiber Bragg grating filters, cascaded fiber Bragg grating filters or bulk grating filters; And / or, the polarization controller (5) is a waveplate polarization controller or an optical fiber polarization controller.

9. A method for fabricating a multi-channel broadband optical communication band optical-atomic interface, implemented using the fabrication apparatus for a multi-channel broadband optical communication band optical-atomic interface as described in any one of claims 1-8, characterized in that, Includes the following steps: Multi-channel broadband atomic frequency combs were prepared in erbium-doped solid materials using optical frequency comb generation technology and frequency chirp modulation technology. The atomic frequency comb performs time-domain multimode storage on one photon from a quantum-correlated photon pair or a quantum-entangled photon pair in a broadband multi-frequency mode multiplexed optical communication band, establishing a quantum correlation or quantum entanglement between the other photon in the quantum-correlated photon pair or the quantum-entangled photon pair and the atomic frequency comb, thus forming a multi-channel broadband optical communication band optical-atomic interface.

10. The method for preparing a multi-channel broadband optical communication band optical-atomic interface according to claim 9, characterized in that, The preparation method of the atomic frequency comb specifically includes the following steps: An optical frequency comb with several comb teeth is generated using optical frequency comb technology. The optical frequency comb is periodically shifted using frequency chirp control technology. The comb teeth are shifted several times at equal intervals within each period. The interval after periodic frequency shifting of each comb tooth is a frequency domain mode. The optical frequency comb with several similar comb teeth becomes a multimode pump light. The multimode pump light is used to pump erbium-doped solid materials. The pump light interacts with the erbium ion ensemble in the erbium-doped solid materials. The corresponding erbium ions in the erbium-doped solid materials are excited using the principle of spectral hole burning. The remaining ground-state erbium ions form a multi-channel atomic frequency comb.

Images