CN210465940U

CN210465940U - Micro-integrated small BBO polarization entanglement source system

Info

Publication number: CN210465940U
Application number: CN201921874226.9U
Authority: CN
Inventors: 宋红岩; 丁禹阳; 陈曹萍; 安雪碧; 程翌婷; 王从柯
Original assignee: Anhui Asky Quantum Technology Co Ltd
Current assignee: Anhui Asky Quantum Technology Co Ltd
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2020-05-05
Anticipated expiration: 2029-10-31

Abstract

The utility model discloses a micro-integrated small BBO polarization entanglement source system, which comprises a hard box body, a pumping light wavelength device, a parameter light band device and a nonlinear crystal; the bottom surfaces of the lenses of the pumping light wavelength device and the parametric light band device and the bottom surface of the nonlinear crystal are respectively fixedly adhered to the bottom plate of the hard box body; and the light transmitting surfaces of the lenses in the pump light wavelength device and the parametric light band device and the nonlinear crystal are vertical to the bottom plate of the hard box body. The bottom surfaces of the lenses of the pump light wavelength device and the parametric light band device and the bottom surface of the nonlinear crystal are respectively bonded on the bottom plate of the hard box body through optical glue or eutectic process. The utility model discloses the size reduces by a wide margin, conveniently carries, and the bonding is firm simultaneously, has improved the anti environmental shock's of system ability.

Description

Micro-integrated small BBO polarization entanglement source system

Technical Field

The utility model relates to a quantum communication field's commercialization or laboratory based on space optical element entangle source equipment, especially relate to a little small-size BBO polarization of integration entangles source system.

Background

Quantum entanglement is a unique and wonderful characteristic of quantum information science, and intuitively reflects the essence of quantum theory: probabilistic and spatially non-localized. The entanglement source is used as a basic physical resource, plays a great role in the application fields of quantum secret communication, quantum precision measurement, quantum calculation and the like, and is an important core resource.

Currently, commercial space-based optical elements or laboratory entanglement source devices are generally fixed by first installing the optical elements into an optical frame and then installing and fixing the optical frame in place. This equipment of product form has three disadvantages: one is that the overall volume of the system is large (the general volume is at least 300 x 150mm) due to the large volume of the general spectacle frame; secondly, the system has small spot size (less than 3mm), and materials are wasted by using conventional large-size optical elements (phi 25.4 mm); third, all adopt the screw fixation for this kind of product, under the condition that has vibrations such as transportation, the screw can take place to become flexible, leads to the device not flexible even drop, and the light path is no longer collimated, and the system can't work.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model provides a little small-size BBO polarization entanglement source system of integration, this little small-size BBO polarization entanglement source system size of integration reduces (reduces to 1/10 at least) by a wide margin, conveniently carries, and the bonding is firm simultaneously, has improved the anti environmental shock's of system ability.

In order to realize the technical purpose, the utility model discloses the technical scheme who takes does: the micro-integrated small BBO polarization entanglement source system comprises a hard box body, a pump light wavelength device, a parameter light band device and a nonlinear crystal; the pump light wavelength device comprises an optical fiber collimator OCA, a focusing lens LensA, a half-wave plate HWPA1, a half-wave plate HWPA2, a polarization beam splitter PBS and an optical garbage Can Can; the parametric optical band device comprises a reflector RR1, a reflector RR2, a lens LensB1, a lens LensB2, a filter IF1, a filter IF2, a collimator OCB1 and a collimator OCB 2; the optical fiber collimator OCA, the collimator OCB1 and the collimator OCB2 respectively penetrate through round holes in the hard box body;

the method is characterized in that: the bottom surfaces of the optical fiber collimator OCA, the focusing lens LensA, the half-wave plate HWPA1, the half-wave plate HWPA2, the polarization beam splitter PBS, the optical garbage Can Can, the reflecting mirror RR1, the reflecting mirror RR2, the lens LensB1, the lens LensB2, the filter IF1, the filter IF2, the collimator OCB1, the collimator OCB2 and the nonlinear crystal are respectively fixedly mounted on the bottom plate of the hard box body in an adhering mode; the light-passing surfaces of the lenses in the pumping light wavelength device and the parametric light band device and the light-passing surfaces of the nonlinear crystals are perpendicular to the bottom plate of the hard box body.

Further, the optical fiber collimator OCA, the focusing lens LensA, the half-wave plate HWPA1, the half-wave plate HWPA2, the polarization beam splitter PBS, the optical trash Can, the mirror RR1, the mirror RR2, the lens LensB1, the lens LensB2, the filter IF1, the filter IF2, the collimator OCB1, the collimator OCB2 and the nonlinear crystal are respectively bonded on the bottom plate of the hard box body through optical glue or a eutectic process.

Further, the nonlinear crystal is a BBO crystal.

Further, the optical trash Can is an optical absorptive attenuation lens or a beam collection Can.

Further, the lens LensA is a plano-convex lens, a biconvex lens or a parabolic lens.

The utility model discloses the outward appearance form is a stereoplasm box body. The box body structure allows the design and processing according to the requirements, such as punching, processing of local structures and the like. The hard box body can be made of metal, ceramic or other non-fragile materials. The OCA can lead laser outside the system into the module through an optical fiber and is used as a pumping light source of the system. The focusing lens LensA is used for focusing light beams, so that light spots of emergent light are reduced, the power density is enhanced, and the generation efficiency of entangled photon pairs is further enhanced. The focusing lens can be an optical lens with focusing function, such as a plano-convex lens, a biconvex lens, a paraboloid lens and the like. The half-wave plates HWPA1 and HWPA2 are used to modulate the pump light source polarization direction to set direction. The polarizing beam splitter PBS is configured to split the light with a horizontal polarization and a vertical polarization direction component, wherein the horizontal polarization is transmitted and the vertical polarization is reflected. When the PBS is used only for polarization selection, a device having a polarization selection function such as a polarizing plate may be used instead. The optical garbage Can be used for collecting residual pump light, and Can be a small-size optical absorptive attenuation lens or a small-size light beam collecting Can. The nonlinear BBO crystal is used for generating a parametric conversion process and generating entangled photon pairs separated from the pump light at a small angle. The reflectors RR1 and RR2 are used to reflect the parametric light into the left and right entangled light collecting paths, and may be sheet reflectors, right-angle reflectors, parabolic reflectors, and other mirrors with reflective function. The parametric optical band lens LensB1 and LensB2 are used for realizing the conversion of the light beam from parallel to focusing or from focusing to parallel light. The filters IF1 and IF2 are used to filter out spatial stray light and residual pump light, ensuring that only the parametric light enters the fiber collimator, which may be narrow band pass or long pass filters. The collimators OCB1 and OCB2 are used to couple the entangled photon pairs from a spatial distribution into the fiber, and the output is measured or directly output for use. Meanwhile, the collimators OCB1 and OCB2 can be adjustable or fixed in focal length. The optical elements are all free of frame mounting. The edge of the optical element is in contact with the bottom plate and is sequentially fixed on the bottom plate, and the light passing surface of the lens is perpendicular to the bottom plate. The specially shaped optical element allows to enhance the fixing effect with the aid of the fixing base. The optical elements are fixed on the bottom plate through processes such as optical glue or eutectic crystal. The size of the light-passing surface of all optical elements is changed according to the size of an incident beam light spot, is slightly larger than the size of the light spot and is generally in the order of 3-5 mm.

The lenses of the optical elements LensA, HWPA1, HWPA2, RR1, RR2, LensB1, LensB2, IF1, IF2 and the like are square thin sheets, and the side length is controlled to be in the mm order, preferably 3-5 mm. The square sheet-like lens can also be designed into a round, edge-cut round or other polygonal lens, and the diameter is controlled to be in the mm order, and is preferably 3-5 mm. The length of the block-shaped optical element, such as a right-angle reflecting prism, a PBS, etc., is controlled to be in the order of mm, preferably 3-5 mm. The centers of the related OCA, LensA, HWPA1, HWPA2, BBO and Can devices are collinear and are sequentially arranged on the same straight light path. The adjacent light-passing surfaces of the OCA, LensA, HWPA1, PBS and HWPA2 are spaced by mm, preferably 1-5 mm. The distance between the nonlinear BBO crystal and the center of the focusing lens LensA is equal to the focal length of LensA. Can is in the order of cm from the BBO crystal, preferably less than 100 mm. The RR1, LensB1, IF1 and OCB1 devices are collinear in center, are sequentially placed on the same straight line light path, and have the adjacent light-passing surface spacing of the order of mm, preferably 1-5 mm. The RR2, LensB2, IF2 and OCB2 devices are collinear in center, are sequentially placed on the same straight line light path, and have the adjacent light-passing surface spacing of the order of mm, preferably 1-5 mm. LensA is confocal with LensB1, LensB2 by a distance equal to the sum of the two focal lengths. The optical element pitch, in addition to the lens related devices described above, may be closely coupled, or may be maintained, on the order of 1-3 mm. The number of optical elements in the system may vary according to functional requirements. The optical element allows the replacement of similar products fulfilling the same function. The optical element dimensions allow for variation according to beam parameters. The inter-optical element distance is allowed to vary depending on device parameters. According to the functional requirements, the system can be added with a polarization analysis element to realize entanglement measurement. On the premise of realizing the function, the front and back positions of the devices in the system are allowed to be freely combined. On the premise of realizing the function, conventional devices such as a reflector and the like are allowed to change the direction of the light path. The entanglement source supports expansion to obtain four maximum entanglement states: a quarter-wave plate QWPA is added in an entanglement generation module to compensate the phase difference between o light and e light, a half-wave plate is added in a collection module, and H, V polarization is replaced, so that HH +/-VV states and HV +/-VH states are obtained. The optical path allows the optical path optical length or the optical path direction to be changed by changing the parameter performance of the device, as shown in figure 3. the optical path allows the optical path optical length or the optical path direction to be changed by adding a conventional device of the device, such as a pumping band reflector RRA and the like, as shown in figure 4.

The utility model discloses exempt the required optical mirror holder of installation lens, reduce the component size simultaneously, control at the mm magnitude, based on technologies such as optical cement or eutectic, directly bond small-size optical element on the bottom plate to realize that entanglement source size reduces by a wide margin (reduces to 1/10 at least), conveniently carry, the bonding is firm simultaneously, has improved the ability of the anti environmental shock of system.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic diagram of the optical path principle of embodiment 1 of the present invention.

Fig. 3 is a schematic diagram of a principle of a deformed light path according to embodiment 1 of the present invention.

Fig. 4 is a schematic diagram of the principle of the optical path after the device is added in embodiment 1 of the present invention.

Detailed Description

Example 1

Referring to fig. 1, the micro-integrated small BBO polarization entanglement source system includes a hard box, a pump optical wavelength device, a parametric optical band device, and a nonlinear crystal; the pump light wavelength device comprises an optical fiber collimator OCA, a focusing lens LensA, a half-wave plate HWPA1, a half-wave plate HWPA2, a polarization beam splitter PBS and an optical garbage Can Can; the parametric optical band device comprises a reflector RR1, a reflector RR2, a lens LensB1, a lens LensB2, a filter IF1, a filter IF2, a collimator OCB1 and a collimator OCB 2; the optical fiber collimator OCA, the collimator OCB1 and the collimator OCB2 respectively penetrate through round holes in the hard box body; the bottom surfaces of the optical fiber collimator OCA, the focusing lens LensA, the half-wave plate HWPA1, the half-wave plate HWPA2, the polarization beam splitter PBS, the optical garbage Can Can, the reflecting mirror RR1, the reflecting mirror RR2, the lens LensB1, the lens LensB2, the filter IF1, the filter IF2, the collimator OCB1, the collimator OCB2 and the nonlinear crystal are respectively fixedly mounted on the bottom plate of the hard box body in an adhering mode; the light-passing surfaces of the lenses in the pumping light wavelength device and the parametric light band device and the light-passing surfaces of the nonlinear crystals are perpendicular to the bottom plate of the hard box body. The optical fiber collimator OCA, the focusing lens LensA, the half-wave plate HWPA1, the half-wave plate HWPA2, the polarization beam splitter PBS, the optical garbage Can Can, the reflector RR1, the reflector RR2, the lens LensB1, the lens LensB2, the filter IF1, the filter IF2, the collimator OCB1, the collimator OCB2 and the nonlinear crystal are respectively bonded on the bottom plate of the hard box body through optical glue or a eutectic process, and the nonlinear crystal is a BBO crystal.

The appearance of the present embodiment 1 is a hard case. The box body is made of aluminum alloy metal and has the size of 160 × 60 × 15 mm. Three round holes are processed on the box body and used for connecting the optical fibers into the optical fiber collimator in the box body. Referring to fig. 2, the present system comprises a pump light wavelength device having: an optical fiber collimator OCA, a focusing lens LensA, a half-wave plate HWPA1, an HWPA2, a polarization beam splitter PBS and an optical garbage Can Can. The system comprises the following parametric optical band devices: mirror RR1, RR2, lens LensB1, LensB2, filter IF1, IF2, and collimators OCB1, OCB 2. The nonlinear crystal contained in the system is BBO crystal. The OCA can lead laser outside the system into the module through an optical fiber and is used as a pumping light source of the system. The focusing lens LensA is used for focusing light beams, so that light spots of emergent light are reduced, the power density is enhanced, and the generation efficiency of entangled photon pairs is further enhanced. The focusing lens can be an optical lens with focusing function, such as a plano-convex lens, a biconvex lens, a paraboloid lens and the like. The half-wave plate is used for modulating the polarization direction of the pump light source to a set direction. The system comprises two pump light half-wave plates HWPA as required. The first half-wave plate HWPA1 is used to tune the pump light source polarization to the PBS transmission polarization and the second HWPA2 is used to tune the PBS transmission horizontal polarization to 45. The polarizing beam splitter PBS is configured to split the light with a horizontal polarization and a vertical polarization direction component, wherein the horizontal polarization is transmitted and the vertical polarization is reflected. When the PBS is used only for polarization selection, a device having a polarization selection function such as a polarizing plate may be used instead. The optical garbage Can be used for collecting residual pump light, and Can be a small-size optical absorptive attenuation lens or a small-size light beam collecting Can. The nonlinear BBO crystal is used for generating a parametric conversion process and generating entangled photon pairs separated from the pump light at a small angle. The reflectors RR1 and RR2 are used to reflect the parametric light into the left and right entangled light collecting paths, and may be sheet reflectors, right-angle reflectors, parabolic reflectors, and other mirrors with reflective function. The parametric optical band lenses LensB1, LenB2 and LensA are confocal to realize the conversion of light beam focusing to parallel light. The filters IF1 and IF2 are used to filter out spatial stray light and residual pump light, ensuring that only the parametric light enters the fiber collimator, which may be narrow band pass or long pass filters. The collimators OCB1 and OCB2 are used to couple the entangled photon pairs from a spatial distribution into the fiber, and the output is measured or directly output for use. Meanwhile, the collimators OCB1 and OCB2 can be adjustable or fixed in focal length.

The optical elements are all free of frame mounting. The edge of the optical element is in contact with the bottom plate and is sequentially fixed on the bottom plate, and the light passing surface of the lens is perpendicular to the bottom plate. The optical elements are all fixed on the bottom plate through optical glue. The spot diameter of the incident beam of the system is about 1 mm. The light-passing surfaces of the optical fiber collimators OCA, OCB1 and OCB2 are phi 11mm in size. The lenses of the optical element LensA, HWPA1, HWPA2, RR1, RR2, LensB1, LensB2, IF1, IF2 and the like are square thin sheets, the side length is 5mm, and the thickness is less than 1 mm. The block optical elements such as right angle reflecting prisms, PBS etc. have dimensions of 5 mm. The centers of the related OCA, LensA, HWP1, PBS, HWP2, BBO and Can devices are collinear and are sequentially arranged on the same straight light path. The RR1, LensB1, IF1 and OCB1 devices are collinear at the center and are sequentially arranged on the same straight light path. The RR2, LensB2, IF2 and OCB2 devices are collinear at the center and are sequentially arranged on the same straight light path.

The adjacent light-passing surfaces of OCA, LensA, HWP1, PBS and HWP2 are all 3mm apart. The distance between the nonlinear BBO crystal and the center of the focusing lens LensA is equal to the focal length of LensA. The lens focal length is 50mm, which varies with the lens parameter. The distance between the BBO and the optical garbage Can is 100 mm. LensA was confocal with LensB1, LensB2, lensB1, LensB2 at 100mm focal length. The distance between the two changes with the change of the focal length. The centers of the two reflectors RR1 and RR2 are 15mm apart, and the optical paths are axisymmetric with the pump light. The distances between adjacent light-passing surfaces of LensB1, IF1 and OCB1 are all 3 mm. The distances between adjacent light-passing surfaces of LensB2, IF2 and OCB2 are all 3 mm. The square sheet-like lens can also be designed into a round, edge-cut round or other polygonal lens, and the diameter is controlled to be in the mm order, and is preferably 3-5 mm. The size of the light-passing surface of all optical elements is changed according to the size of an incident beam light spot, is slightly larger than the size of the light spot and is generally in the order of 3-5 mm. The number of optical elements in the system may vary according to functional requirements.

The optical element allows the replacement of similar products fulfilling the same function. The optical element dimensions allow for variation according to beam parameters. The inter-optical element distance is allowed to vary depending on device parameters. According to the functional requirements, the system can be added with a polarization analysis element to realize entanglement measurement. On the premise of realizing the function, the front and back positions of the devices in the system are allowed to be freely combined. On the premise of realizing the function, conventional devices such as a reflector and the like are allowed to change the direction of the light path. The entanglement source supports expansion to obtain four maximum entanglement states: adding quarter QWPA wave plate in entanglement generation module to compensate phase difference between o light and e light, adding half wave plate in collection module to replace H, V polarization so as to obtain HH + -VV state and HV + -VH state.

Fig. 2 is a schematic diagram of the optical path principle of the present embodiment 1, which allows the optical path optical length or the optical path direction to be changed by changing the device parameter performance, as shown in fig. 3, and allows the optical path optical length or the optical path direction to be changed by adding a device conventional device, such as a pumping band mirror RRA, etc., as shown in fig. 4.

Claims

1. A micro-integrated small BBO polarization entanglement source system comprises a hard box body, a pump light wavelength device, a parameter light band device and a nonlinear crystal; the pump light wavelength device comprises an optical fiber collimator OCA, a focusing lens LensA, a half-wave plate HWPA1, a half-wave plate HWPA2, a polarization beam splitter PBS and an optical garbage Can Can; the parametric optical band device comprises a reflector RR1, a reflector RR2, a lens LensB1, a lens LensB2, a filter IF1, a filter IF2, a collimator OCB1 and a collimator OCB 2; the optical fiber collimator OCA, the collimator OCB1 and the collimator OCB2 respectively penetrate through round holes in the hard box body;

2. The micro-integrated small BBO polarization entanglement source system of claim 1, wherein: the optical fiber collimator OCA, the focusing lens LensA, the half-wave plate HWPA1, the half-wave plate HWPA2, the polarization beam splitter PBS, the optical garbage Can Can, the reflector RR1, the reflector RR2, the lens LensB1, the lens LensB2, the filter IF1, the filter IF2, the collimator OCB1, the collimator OCB2 and the nonlinear crystal are respectively bonded on the bottom plate of the hard box body through optical glue or a eutectic process.

3. The micro-integrated small BBO polarization entanglement source system of claim 1, wherein: the nonlinear crystal is BBO crystal.

4. The micro-integrated small BBO polarization entanglement source system of claim 1, wherein: the optical trash Can is an optical absorptive attenuating lens or a beam collection Can.

5. The micro-integrated small BBO polarization entanglement source system of claim 1, wherein: the focusing lens LensA is a plano-convex mirror, a biconvex mirror or a paraboloid mirror.