CN211743663U

CN211743663U - Photon source-to-source integration module

Info

Publication number: CN211743663U
Application number: CN202020616190.0U
Authority: CN
Inventors: 李萍
Original assignee: Tianjin Lingxin Technology Development Co ltd
Current assignee: Tianjin Lingxin Technology Development Co ltd
Priority date: 2020-04-22
Filing date: 2020-04-22
Publication date: 2020-10-23
Anticipated expiration: 2030-04-22

Abstract

The application relates to a photon pair source integrated module which comprises a laser, a polarization controller, an optical frequency doubling component, a wavelength division multiplexer and a photon pair source component which are connected in sequence, wherein the laser outputs a first laser beam; the polarization controller adjusts the polarization state of the laser beam; the optical frequency doubling component doubles the frequency of the laser beam to obtain a second laser beam; the wavelength division multiplexer is used for filtering the second laser beam; the photon pair source component obtains the photon pair by using the filtered second laser beam through the spontaneous parameter down-conversion process, solves the technical problems that the output brightness of the photon pair source is not high enough, the whole equipment has large volume and high cost, and is difficult to integrate with the photon pair source in the prior art, achieves higher output light power, and is beneficial to improving the technical effect of the brightness of the photon pair source.

Description

Photon source-to-source integration module

Technical Field

The application relates to the technical field of quantum optics and quantum communication, in particular to a photon source-source integrated module.

Background

At present, a quantum source with entanglement characteristics is a core component in technologies such as quantum information, quantum computation, quantum sensing and the like, wherein a photon pair source with polarization entanglement characteristics can be fully compatible with a current mature optical polarization element and a 1.5-micrometer waveband optical fiber communication technology, so that the quantum source is paid wide attention and applied in practical engineering application of quantum technology.

In the prior art, the photon pair generated by conversion under the spontaneous parameters of nonlinear optical crystals such as barium metaborate (BBO), Periodically Polarized Lithium Niobate (PPLN), periodically polarized potassium titanyl phosphate (PPKTP) and the like can realize quantum entanglement phenomena of multiple dimensions such as polarization entanglement, time-energy entanglement, angular momentum entanglement, position-momentum entanglement and the like, wherein the polarization entanglement characteristic of the photon pair is most widely researched and applied.

Through the spontaneous parametric down-conversion process of the nonlinear optical crystal, the pumping light source with the wavelength of 765 nm-785 nm can generate photon pairs with the wavelength of C band (1530 nm-1570 nm). In the nonlinear optical action process, the number of the obtained photon pairs, namely the brightness of the photon pair source, has a direct relation with the power of the pump light source, the nonlinear conversion efficiency and the optical waveguide loss, and the higher the power of the pump light source, the higher the nonlinear conversion efficiency and the lower the optical waveguide loss are, the higher the number of the photon pairs is and the higher the brightness of the photon pair source is.

However, in the prior art, a semiconductor laser with a wavelength of 765nm to 785nm is often used as a pump laser of a photon pair source, so that the overall equipment has the problems of large volume, high cost, difficulty in integrating with the photon pair source, low output optical power (about 100mW), low brightness of the obtained photon pair source and the like, and the improvement, miniaturization, integration and practical engineering application of the brightness of the photon pair source are greatly limited.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problems that the existing photon pair source output brightness is not high enough, the whole volume of equipment is large, the cost is high, and the integration with a photon pair source is difficult, or at least partially solve the technical problems, the application provides a photon pair source integration module which can have higher output optical power and is beneficial to improving the brightness of the photon pair source.

In a first aspect, the present application provides a photon pair source integration module comprising: the device comprises a laser, a polarization controller, an optical frequency doubling component, a wavelength division multiplexer and a photon pair source component which are connected in sequence;

the laser is used for outputting a first laser beam;

the polarization controller is used for adjusting the polarization state of the first laser beam;

the optical frequency doubling component is used for doubling the frequency of the first laser beam to obtain a second laser beam;

the wavelength division multiplexer is used for filtering the second laser beam;

and the photon pair source component is used for obtaining photon pairs through a spontaneous parametric down-conversion process by using the second laser beams after being filtered.

Optionally, the optical frequency doubling component includes a first substrate wafer, a first optical waveguide, a first periodic polarization structure, a first optical fiber crystal carrier block, a first input optical fiber, a first output optical fiber, and a first wafer temperature control stage;

the first substrate wafer is fixedly placed on the first wafer temperature control table;

the first optical waveguide is formed on the surface of the first substrate wafer;

the first periodic polarization structure is arranged on the surface of the first substrate wafer and is arranged along the light wave transmission direction of the first light waveguide;

the first optical waveguide comprises a first strip optical waveguide and a first tapered optical waveguide;

the first input optical fiber is coupled and connected with the input end of the first strip-shaped optical waveguide through one first optical fiber crystal carrier block;

the output end of the first strip-shaped optical waveguide is connected with the input end of the first tapered optical waveguide;

the first output optical fiber is coupled with the output end of the first tapered optical waveguide through one first optical fiber crystal carrier block.

Optionally, the first input optical fiber includes a single-mode optical fiber with a wavelength range of 1500nm to 1600 nm; the first output optical fiber comprises a single mode optical fiber within the wavelength range of 750-800 nm.

Optionally, a first crystal pad block is disposed on both side edges of the first substrate wafer close to the first optical fiber crystal carrier block.

Optionally, the photon pair source assembly includes a second substrate wafer, a second optical waveguide, a second periodic polarization structure, a second crystal spacer, a second fiber crystal carrier, a second input fiber, a second output fiber, and a second wafer temperature control stage;

the second substrate wafer is fixedly placed on the second wafer temperature control table;

the second optical waveguide is formed on the surface of the second substrate wafer;

the second periodic polarization structure is arranged on the surface of the second substrate wafer and is arranged along the light wave transmission direction of the second optical waveguide;

the second optical waveguide comprises a second strip-shaped optical waveguide and a second conical optical waveguide;

the second input optical fiber is coupled and connected with the input end of the second tapered optical waveguide through one second optical fiber crystal carrier block;

the output end of the second tapered optical waveguide is connected with the input end of the second strip-shaped optical waveguide;

the second output optical fiber is coupled and connected with the output end of the second strip-shaped optical waveguide through one second optical fiber crystal carrier block.

Optionally, the second input optical fiber includes a single-mode optical fiber within a wavelength range of 750-800 nm; the second output optical fiber comprises a single mode optical fiber within the wavelength range of 1500nm to 1600 nm.

Optionally, a second crystal pad is disposed on both side edges of the second substrate wafer close to the second optical fiber crystal carrier.

Optionally, the laser comprises an erbium doped fibre laser.

Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages: the embodiment of the application integrates devices such as a laser, a polarization controller, a wavelength division multiplexer, an optical frequency doubling component and a photon source component by providing the photon source integrating module, so that the whole volume of the device is small, the cost is low, higher output optical power can be realized, and the improvement of the brightness of photons to a source is facilitated.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

Fig. 1 is a schematic composition diagram of a photon pair source integrated module according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of an optical frequency doubling module according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a photon pair source assembly according to an embodiment of the present application.

Icon:

1. a laser; 2. a polarization controller; 3. an optical frequency doubling component; 4. a wavelength division multiplexer; 5. a photon pair source assembly; 31. a first base wafer; 32. a first optical waveguide; 321. a first strip-shaped optical waveguide; 322. a first tapered optical waveguide; 33. a first periodic poled structure; 34. a first fiber crystal carrier block; 35. a first input optical fiber; 36. a first output optical fiber; 37. a first wafer temperature control stage; 38. a first crystal block; 51. a second base wafer; 52. a second optical waveguide; 521. a second strip-shaped optical waveguide; 522. a second tapered optical waveguide; 53. a second periodic poled structure; 54. a second fiber crystal carrier block; 55. a second input optical fiber; 56. a second output optical fiber; 57. a second wafer temperature control stage; 58. a second crystal spacer.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

However, in the prior art, a semiconductor laser with a wavelength of 765nm to 785nm is often used as a pump laser of a photon pair source, and the overall size of the device is large, the cost is high, the integration with the photon pair source is difficult, and the output optical power is low (about 100mW), which causes the problem that the brightness of the obtained photon pair source is not high enough, so that the improvement, miniaturization, integration and practical engineering application of the brightness of the photon pair source are limited to a large extent.

For easy understanding, the photon pair source integrated module provided in the embodiments of the present application is described in detail below, and referring to fig. 1, the photon pair source integrated module may include a laser 1, a polarization controller 2, an optical frequency doubling assembly 3, a wavelength division multiplexer 4, and a photon pair source assembly 5, which are connected in sequence;

the laser 1 is used for outputting a first laser beam;

the polarization controller 2 is used for adjusting the polarization state of the first laser beam;

the optical frequency doubling component 3 is used for frequency doubling the first laser beam to obtain a second laser beam;

the wavelength division multiplexer 4 is used for filtering the second laser beam;

the photon pair source assembly 5 is configured to obtain photon pairs through a spontaneous parametric down-conversion process using the filtered second laser beam.

Here, in some embodiments of the present application, the laser 1 may include an erbium-doped fiber laser 1, where the laser 1 may generate and output a first laser beam, where the frequency of the first laser beam is denoted as ω 1 (or the wavelength is λ 1); the laser 1 may be an erbium-doped fiber laser 1 with a narrow linewidth, the wavelength of the output first laser beam is in the C-band, and the output optical power is not less than 1 mW. The laser 1 may be a continuous light output or a pulsed light output, and is not particularly limited herein.

Here, the polarization controller 2 may be configured to adjust a polarization state of the first laser beam output by the laser 1, so as to ensure that a second laser beam obtained after the first laser beam is frequency-doubled by the optical frequency doubling component 3 is optimal nonlinear optical frequency doubling efficiency and maximum frequency doubling optical power output. Here, as an example, the polarization controller 2 may be a manual type polarization controller such as a three-ring type optical fiber polarization controller or a squeeze type optical fiber polarization controller; and the polarization controller can also be an electric polarization controller, such as an electric polarization controller based on an optical fiber squeezer or an electric polarization controller based on an electro-optical crystal. Here, to achieve the maximum degree of integration and intelligent use, as a preferred example, an electrically controlled polarization controller based on an electro-optical crystal optical waveguide may be used.

Here, the optical frequency doubling module 3 may obtain the second laser beam with the frequency ω 2 ═ 2 ω 1 (or the wavelength λ 1/2) by the optical nonlinear process of frequency doubling of the first laser beam with the frequency ω 1 (or the wavelength λ 1) generated by the laser 1 through the optical frequency doubling module 3. For example, a first laser beam with a wavelength of 1560nm generated by the laser 1 can pass through the optical frequency doubling component 3 to obtain a frequency doubled laser beam with a wavelength of 780nm, i.e., a second laser beam.

Here, the wavelength division multiplexer 4 may be disposed between the optical frequency doubling module 3 and the photon pair source module 5, and may be configured to filter the first laser beam output from the optical frequency doubling module 3, where as described in connection with the above example, the wavelength division multiplexer 4 may filter the first laser beam output from the optical frequency doubling module 3 and the frequency doubling laser beam having a wavelength of 1530nm to 1570nm, that is, the second laser beam, so as to prevent the first laser beam having a wavelength of 1530nm to 1570nm from entering the photon pair source module 5, and causing a noise effect on the detection of photons.

Here, as described in connection with the above example, the photon pair source assembly 5 may use the frequency-doubled laser beam having the frequency ω 2 generated by the optical frequency doubling assembly 3, i.e., the second laser beam, as the pump light, and obtain the photon pairs having the frequencies ω 3 and ω 4 through the optical nonlinear process of spontaneous parametric down-conversion. Here, the photon pairs with frequencies ω 3 and ω 4 may be modes with the same polarization, or may be modes with orthogonal polarizations; the photon pairs may have the same frequency, i.e., ω 3 ≠ ω 4, or different frequencies, i.e., ω 3 ≠ ω 4, but the frequencies of the photon pairs need to satisfy the energy conservation condition, i.e., h ω 3+ h ω 4 ═ h ω 2.

The photon source-to-source integration module provided by the embodiment of the application integrates devices such as the laser 1, the polarization controller 2 and the wavelength division multiplexer 4 with the optical frequency doubling component 3 and the photon source-to-source component 5, has small overall volume and low cost, can have higher output optical power, and is favorable for improving the brightness of photons to a source.

In some embodiments of the present application, referring to fig. 2, the optical frequency doubling assembly 3 includes a first substrate wafer 31, a first optical waveguide 32, a first periodic polarization structure 33, a first fiber crystal carrier block 34, a first input optical fiber 35, a first output optical fiber 36, and a first wafer temperature control stage 37;

the first substrate wafer 31 is fixedly placed on the first wafer temperature control stage 37;

the first optical waveguide 32 is formed on the surface of the first base wafer 31;

the first periodic polarization structure 33 is arranged on the surface of the first substrate wafer 31 and arranged along the light wave transmission direction of the first light waveguide 32;

the first optical waveguide 32 includes a first strip optical waveguide 321 and a first tapered optical waveguide 322;

the first input optical fiber 35 is coupled to the input end of the first strip-shaped optical waveguide 321 via a first fiber crystal carrier block 34;

the output end of the first strip optical waveguide 321 is connected to the input end of the first tapered optical waveguide 322;

the first output fiber 36 is coupled to the output of the first tapered optical waveguide 322 via a first fiber crystal carrier 34.

Here, the first wafer temperature control stage 37 may be used, on the one hand, to place and hold the first substrate wafer 31, and on the other hand, to perform temperature control of the first substrate wafer 31 and the first optical waveguide 32 formed therein, for example, heating in a temperature range from room temperature to 250 ℃ and temperature control with ± 1 ℃ accuracy may be performed.

Here, the first base wafer 31 may be an optical crystal having a nonlinear optical effect, and may be one of optical crystal materials of lithium niobate, lithium tantalate, potassium titanyl phosphate and the like, or one of special optical crystal materials of near-stoichiometric lithium niobate or lithium tantalate crystal, magnesium oxide-doped or magnesium-doped lithium niobate or lithium tantalate crystal and the like. Magnesium oxide doped lithium niobate crystals are preferably used. As an example, the first substrate wafer 31 may have a crystal tangent of Z-cut with a thickness of 0.1mm to 2.0mm, preferably 0.5 mm.

In order to reduce the loss of light energy due to back reflection or fresnel reflection, the first substrate wafer 31 is polished to an inclination angle of not more than 15 °, or alternatively, the first substrate wafer 31 may be coated with an antireflection film.

Here, the first optical waveguide 32 may be formed on the surface of the first base wafer 31 in one of the following two ways:

(1) for the nonlinear optical effect of class I quasi-phase matching, the first optical waveguide 32 may adopt one of the forming manners of annealing proton exchange or anti-proton exchange, etc., to realize the transmission of a single polarization mode;

(2) for the nonlinear optical effect of the class II quasi-phase matching, the first optical waveguide 32 may adopt one of the formation modes of titanium diffusion, zinc oxide diffusion, and the like, to realize the transmission of the dual polarization mode.

The first optical waveguide 32 may be an optical waveguide having a ridge-shaped protrusion formed by wet etching, dry etching, precision optical cutting, or other techniques. Of course, a combination of the above-described means may be used, for example, a titanium diffused optical waveguide formed with ridge-shaped projections.

Here, the first periodic polarization structures 33 may be formed on the surface of the first base wafer 31 and at the first optical waveguides 32, respectively, with their periodic structure distribution direction being the same as the optical wave transmission direction of the first optical waveguides 32.

Here, the polarization period Λ of the first periodic polarization structure 33 may be one of three ranges: 6-9 μm, 18-21 μm and 27-34 μm, and the polarization period Λ is designed to satisfy the following formula: Λ is 2 pi/(kp-ks + ki). Taking the photon pair generation process as an example, kp represents the wave vector of the pump light, ks represents the wave vector of the signal light, and ki represents the wave vector of the idler light.

Here, in the first substrate wafer 31, the waveguide width of the first tapered optical waveguide 322 is linearly narrowed, and the initial waveguide width thereof is the same as the width of the strip-shaped optical waveguide, for example, the waveguide width at an operating wavelength of 1560nm is 6 μm to 8 μm, and the waveguide width is linearly narrowed to an operating wavelength of 780nm is 1 μm to 3 μm. The length of the first tapered optical waveguide 322 may be no less than 1 mm. The length of the first strip optical waveguide 321 may be not less than 10 mm.

Here, the first laser beam may enter from the first strip-shaped optical waveguide 321, and a frequency-doubled laser beam obtained through the nonlinear frequency conversion of the first periodic polarization structure 33 is a second laser beam, where the second laser beam may be mixed with the incident first laser beam, and the incident first laser beam is filtered through the optical wave mode filtering of the first tapered optical waveguide 322 to maintain the single-mode state output of the frequency-doubled laser beam, i.e., the second laser beam.

Here, the first strip optical waveguide 321 and the first tapered optical waveguide 322 formed in the first base wafer 31 are zinc oxide diffused optical waveguides. The optical frequency doubling component 3 based on the zinc oxide diffusion optical waveguide can realize the conversion of the wave direction of the laser beam in the C wave band to 765 nm-785 nm. The zinc oxide diffusion optical waveguide has high optical damage resistance, so that a high-power C-waveband laser beam can be used, and the optical power of a frequency doubling laser beam, namely a second laser beam, in the 765-785 nm wavelength range obtained through nonlinear frequency conversion is higher.

In some embodiments of the present application, the first input fiber 35 may comprise a single mode fiber in the wavelength range of 1500nm to 1600 nm; the first output fiber 36 may comprise a single mode fiber in the wavelength range of 750-800 nm.

Here, the first input fiber 35 may be coupled to an input end of the first strip optical waveguide 321, and the first input fiber 35 may be a single mode fiber in a wavelength range of 1500nm to 1600nm, a polarization maintaining single mode fiber, or a non-polarization maintaining single mode fiber. The first output fiber 36 may be coupled to the output end of the first tapered optical waveguide 322, and the first output fiber 36 may be a single mode fiber within a wavelength range of 750-800 nm, and may be a polarization-maintaining single mode fiber or a non-polarization-maintaining single mode fiber.

Here, in some embodiments of the present application, the two fiber crystal carrier blocks may be respectively provided with fiber placing openings for placing the first input fiber 35 and the first output fiber 36, where the fiber placing openings may refer to grooves or through holes for placing fibers, and as an example, the fiber crystal carrier block may be a square or rectangular crystal, and the surface of the fiber crystal carrier block is pre-fabricated with a fiber placing opening having a groove of one of V-shape, square shape, semi-circular shape, or the fiber crystal carrier block may be a circular crystal or D-shaped crystal, and the center of the fiber crystal carrier block may be formed with a fiber placing opening having a circular hole shape. Here, the space between the first input optical fiber 35 and the first output optical fiber 36 and the optical fiber placing port may be filled with ultraviolet glue and exposed by ultraviolet light to be sufficiently cured, and then coupled and bonded with the first optical waveguide 32 after polishing. The first fiber crystal carrier block 34 may be made of a crystal material such as lithium niobate, lithium tantalate, quartz, glass, or silicon, and is not particularly limited. As a preferred example, the first fiber crystal carrier block 34 may be a D-shaped glass circular tube with a circular hole formed in the center. In some embodiments of the present application, to obtain the best coupling efficiency with the first optical waveguide 32, the first fiber crystal carrier block 34 may be correspondingly polished to a tilt angle of no more than 15 °.

In order to increase the bonding area and bonding strength when the first fiber crystal carrier block 34 is coupled and bonded to the first substrate wafer 31, in some embodiments of the present application, a first crystal spacer 38 is disposed on each of two side edges of the first substrate wafer 31 near the first fiber crystal carrier block 34. In some embodiments of the present application, the thickness of the first crystal spacer 38 may be not less than 0.5mm, and the first crystal spacer 38 may be selected to have the same crystal material and crystal tangent as the first base wafer 31 to ensure that the first crystal spacer 38 has the same thermal expansion characteristics as the first base wafer 31.

In some embodiments of the present application, referring to fig. 3, photon pair source assembly 5 comprises a second base wafer 51, a second optical waveguide 52, a second periodic polarization structure 53, a second fiber crystal carrier block 54, a second input fiber 5655, a second output fiber, and a second wafer temperature control stage 57;

the second substrate wafer 51 is fixedly placed on the second wafer temperature control stage 57;

the second optical waveguide 52 is formed on the surface of the second base wafer 51;

second periodic polarization structures 53 are arranged on the surface of second substrate wafer 51 and arranged along the light wave transmission direction of second light waveguide 52;

the second optical waveguide 52 includes a second strip optical waveguide 521 and a second tapered optical waveguide 522;

the second input optical fiber 55 is coupled to the input end of the second tapered optical waveguide 522 via a second fiber crystal carrier block 54;

the output end of the second tapered optical waveguide 522 is connected with the input end of the second strip optical waveguide 521;

the second output fiber 56 is coupled to the output end of the second strip optical waveguide 521 via a second fiber crystal carrier 54.

Here, the working principle and structure of the second substrate wafer 51 can refer to the first substrate wafer 31, and the two principles are the same and are not described herein; similarly, the second wafer temperature control stage 57 can be referred to the description of the first wafer temperature control stage 37, and the second fiber crystal carrier block 54 can be referred to the description of the first fiber crystal carrier block 34, which is not described herein again. Here, the second optical waveguide 52 is formed on the surface of the second substrate wafer 51, and the forming manner of the second optical waveguide 52 may refer to the forming manner of the first optical waveguide 32, which is not described herein again; here, the second optical waveguide 52 includes a second strip optical waveguide 521 and a second tapered optical waveguide 522; here, the polarization period of the second periodic polarization structure 53 can be described as the planned period of the first periodic polarization structure 33, and is not described herein again; here, the second substrate wafer 51 may also be plated with an antireflection film, and here, as described in conjunction with the above example, as one example, the light input end face of the first substrate wafer 31 may be plated with an antireflection film of 1530nm to 1570nm, and the light output end face may be plated with an antireflection film of 765nm to 785 nm; the light input end surface of the second substrate wafer 51 may be coated with an anti-reflection film of 765nm to 785nm, and the light output end surface may be coated with an anti-reflection film of 1530nm to 1570 nm.

Here, as one preferable example, the second strip optical waveguide 521 and the second tapered optical waveguide 522 formed in the second base wafer 51 may be an antiproton exchange optical waveguide. Here, in the second substrate wafer 51, the waveguide width of the second tapered optical waveguide 522 is linearly widened from its initial waveguide width to the same width as the second strip optical waveguide 521. For example, from 1 μm to 3 μm at an operating wavelength of 780nm to 6 μm to 8 μm at an operating wavelength of 1560 nm. The length of the second tapered optical waveguide 522 is not less than 1 mm. The length of the second strip optical waveguide 521 is not less than 10 mm. The second tapered optical waveguide 522 may be used to achieve single mode excitation of the frequency doubled beam, i.e. the second laser beam, in the second substrate wafer 51 to achieve optimal nonlinear conversion efficiency of the photon pair generation process.

In some embodiments of the present application, the second input fiber 55 comprises a single mode fiber in the wavelength range of 750-800 nm; the second output fibre 56 comprises a single mode fibre in the wavelength range 1500nm to 1600 nm. Here, the second input fiber 55 may be coupled to the input end of the second tapered optical waveguide 522, and the second input fiber 55 may be a single mode fiber within a wavelength range of 750 to 800nm, a polarization-maintaining single mode fiber, or a non-polarization-maintaining single mode fiber. The second output fiber 56 may be coupled to an output end of the second strip optical waveguide 521, and the second output fiber 56 may be a single-mode fiber within a wavelength range of 1500nm to 1600nm, and may be a polarization-maintaining single-mode fiber or a non-polarization-maintaining single-mode fiber.

In some embodiments of the present application, a second crystal pad 58 is disposed on each of two side edges of the second substrate wafer 51 near the second fiber crystal carrier block 54. The principle and function of the second crystal pad 58 can be referred to the description of the first crystal pad 38, and will not be described herein.

The photon pair source integration module provided by the embodiment of the application adopts the nonlinear optical waveguide crystal with high frequency doubling efficiency to convert the output light wave of the high-power erbium-doped fiber laser 1 with the wavelength in the C wave band to 765 nm-785 nm, has higher output light power compared with the existing semiconductor laser, and is beneficial to improving the brightness of photon pair sources; by highly integrating the active or passive optical fiber devices such as the erbium-doped fiber laser 1, the polarization controller 2, the wavelength division multiplexer 4 and the like with the optical frequency doubling component 3 and the photon pair source component 5, compared with the existing laboratory technical scheme of adopting discrete optical elements and instrument equipment to build a photon pair source, the high-integration-level photonic frequency doubling component has higher integration level, smaller volume, higher reliability and lower cost. The pumping light source, the photon pair source and the wavelength division multiplexer 4 are integrated through optical fibers, the output light of the high-power erbium-doped fiber laser 1 is converted to 765 nm-785 nm through the nonlinear frequency doubling effect by adopting the nonlinear optical waveguide crystal with high frequency doubling efficiency, and the frequency doubling laser beam is used as the pumping light source in the conversion process under the spontaneous parameters. The photon pair source integration module has the characteristics of high brightness, high integration level, low cost and the like, and is favorable for realizing engineering application of a photon pair source in the technical fields of quantum communication, quantum computation and the like.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above description is only exemplary of the invention, and is intended to enable those skilled in the art to understand and implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photonic pair source integrated module, comprising: the device comprises a laser, a polarization controller, an optical frequency doubling component, a wavelength division multiplexer and a photon pair source component which are connected in sequence;

the laser is used for outputting a first laser beam;

2. The photonic pair source integrated module of claim 1, wherein the optical frequency doubling component comprises a first base wafer, a first optical waveguide, a first periodic polarization structure, a first fiber crystal carrier block, a first input fiber, a first output fiber, and a first wafer temperature control stage;

3. The photon pair source integration module of claim 2, wherein the first input fiber comprises a single mode fiber in the wavelength range of 1500nm to 1600 nm; the first output optical fiber comprises a single mode optical fiber within the wavelength range of 750-800 nm.

4. The photon pair source integration module of claim 2, wherein the first base wafer has a first crystal spacer disposed adjacent to each of two side edges of the first fiber crystal carrier.

5. The photonic pair source integrated module of claim 1, wherein the photonic pair source assembly comprises a second base wafer, a second optical waveguide, a second periodic polarization structure, a second crystal spacer, a second fiber crystal carrier, a second input fiber, a second output fiber, and a second wafer temperature control stage;

6. The photon pair source integration module of claim 5, wherein the second input fiber comprises a single mode fiber in the wavelength range of 750-800 nm; the second output optical fiber comprises a single mode optical fiber within the wavelength range of 1500nm to 1600 nm.

7. The photon pair source integration module of claim 5, wherein the second base wafer has a second crystal spacer block disposed on each of two side edges thereof adjacent to the second fiber crystal carrier block.

8. The photonic pair source integrated module of claim 1, wherein the laser comprises an erbium doped fiber laser.