Circulator and optical module

Abstract

The utility model relates to the technical field of optical communication, and relates to a circulator and an optical module. The circulator comprises a first optical fiber, a second optical fiber, a third optical fiber, a light splitting and combining element, a first polarization unit, a second polarization unit, a third polarization unit and a reflection unit, first incident light is split to output o light and e light, and the e light is reflected to enter the second polarization unit and then is transmitted to the light splitting and combining element; the o light is converted into e light through the first polarization unit, the e light is reflected to enter the second polarization unit to be converted into o light and then transmitted to the light splitting and combining element, and the o light and the e light are combined and then output through the second optical fiber; the second incident light outputs o light and e light through light splitting, the e light enters the second polarization unit to be converted into o light, then enters the third polarization unit through reflection, then is converted into e light through the third polarization unit and then is transmitted to the light splitting and combining element, the o light passes through the second polarization unit and then is reflected into the light splitting and combining element, and the o light and the e light are combined and then output through the third optical fiber. The circulator is short in size, and miniaturization of the circulator is facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of optical communication, in particular to a circulator and an optical module. Background Art

[0002] A circulator is one of the commonly used devices in the optical communication industry. The high isolation effect of the circulator is widely used for signal transmission. Among them, a three-port circulator has three ports in different directions, and different ports are connected to corresponding communication ports to achieve the purpose of signal transmission.

[0003] In the related art, as Figure 1 shown, the circulator includes a first lens 110, a first polarization beam splitter 120, a first optical rotation unit 130, a second polarization beam splitter 140, a second optical rotation unit 150, a third polarization beam splitter 160, and a second lens 170 arranged in sequence. The incident light of the first optical fiber 180 passes through the first lens 110, the first polarization beam splitter 120, the first optical rotation unit 130, the second polarization beam splitter 140, the second optical rotation unit 150, the third polarization beam splitter 160, and the second lens 170 in sequence and is output through the second optical fiber 190. The incident light of the second optical fiber 190 passes through the second lens 170, the third polarization beam splitter 160, the second optical rotation unit 150, the second polarization beam splitter 140, the first optical rotation unit 130, the first polarization beam splitter 120, and the first lens 110 in sequence and is output through the third optical fiber 200 to achieve the transmission of optical signals.

[0004] However, in the above solution, the size of the circulator is relatively long, which is not conducive to the miniaturization of the overall device. Summary of the Utility Model

[0005] The technical problem to be solved by the embodiments of the utility model is to provide a circulator and an optical module to solve the problem that the size of the circulator in the prior art is relatively long and not conducive to the miniaturization of the overall device.

[0006] The utility model discloses a circulator, which includes a first optical fiber, a second optical fiber, a third optical fiber, a beam combining / splitting element, a first polarization unit, a second polarization unit, a third polarization unit, and a reflection unit. Among them,

[0007] The first incident light incident from the first optical fiber is split by the beam combining / splitting element into an o-ray and an e-ray. The e-ray is incident on the reflection unit, reflected by the reflection unit, enters the second polarization unit to change the polarization state, and then is transmitted to the beam combining / splitting element. The o-ray changes the polarization state through the first polarization unit and is converted into an e-ray, which is incident on the reflection unit, reflected by the reflection unit, enters the second polarization unit to change the polarization state and is converted into an o-ray, and then is transmitted to the beam combining / splitting element. The beam combining / splitting element combines the o-ray and the e-ray and outputs them through the second optical fiber;

[0008] The second incident light incident from the second optical fiber is split by the optical combiner / splitter into an o-ray and an e-ray. The e-ray is incident on the second polarization unit, changes its polarization state and is converted into an o-ray, then is incident on the reflection unit, and after being reflected by the reflection unit, enters the third polarization unit. After changing its polarization state through the third polarization unit and being converted into an e-ray, it is transmitted to the optical combiner / splitter. The o-ray output by splitting is incident on the second polarization unit after changing its polarization state, and after being reflected by the reflection unit, enters the optical combiner / splitter. The optical combiner / splitter combines the o-ray and the e-ray and outputs them through the third optical fiber.

[0009] Optionally, the first polarization unit includes a first half-wave plate. The o-ray output by splitting of the optical combiner / splitter is incident on the reflection unit after changing its polarization state and being converted into an e-ray through the first half-wave plate.

[0010] Optionally, the second polarization unit includes a second half-wave plate, a third half-wave plate and a rotatory polarizer. The second half-wave plate and the third half-wave plate are located on the same side of the rotatory polarizer, and the first half-wave plate and the second half-wave plate are arranged side by side and attached along a first direction, the second half-wave plate and the third half-wave plate are arranged side by side and attached along a second direction. The first direction and the second direction are perpendicular to each other and both are perpendicular to the direction of the light output by the optical combiner / splitter.

[0011] In the transmission direction of the first incident light, the e-ray output by splitting is incident on the reflection unit, and after being reflected by the reflection unit, sequentially passes through the rotatory polarizer and the second half-wave plate, changes its polarization state and is transmitted to the optical combiner / splitter. The o-ray output by splitting is incident on the reflection unit after changing its polarization state and being converted into an e-ray through the first half-wave plate, and after being reflected by the reflection unit, sequentially passes through the rotatory polarizer and the third half-wave plate, changes its polarization state and is converted into an o-ray and then is transmitted to the optical combiner / splitter.

[0012] In the transmission direction of the second incident light, the o-ray output by splitting sequentially passes through the third half-wave plate and the rotatory polarizer, changes its polarization state and is incident on the reflection unit, and the e-ray output by splitting sequentially passes through the second half-wave plate and the rotatory polarizer, changes its polarization state and is converted into an o-ray and then is incident on the reflection unit.

[0013] Optionally, the third polarization unit includes a fourth half-wave plate. The first half-wave plate, the second half-wave plate and the fourth half-wave plate are arranged side by side and attached in sequence along the first direction. In the transmission direction of the second incident light, the o-ray output by splitting sequentially passes through the fourth half-wave plate and the rotatory polarizer, changes its polarization state and is incident on the reflection unit, and after being reflected by the reflection unit, is incident on the fourth half-wave plate, and after changing its polarization state through the fourth half-wave plate and being converted into an e-ray, is incident on the optical combiner / splitter.

[0014] Optionally, the optical axis angles of the first half-wave plate and the fourth half-wave plate are both 45 degrees, the optical axis angles of the second half-wave plate and the third half-wave plate are both 22.5 degrees, and the optical rotation plate is a 45-degree optical rotation plate.

[0015] Optionally, the reflection unit includes a reflection prism, which is provided with a first reflection surface, a second reflection surface, a third reflection surface, and a fourth reflection surface. In the transmission direction of the first incident light, the e-light output by beam splitting and the e-light output by the first polarization unit are both incident on the second polarization unit after being reflected by the first reflection surface and the second reflection surface in sequence; in the transmission direction of the second incident light, the e-light output by beam splitting is incident on the second polarization unit, changes its polarization state to become o-light, and then is incident on the third polarization unit after being reflected by the third reflection surface and the fourth reflection surface in sequence. The o-light output by beam splitting is incident on the beam splitting / combining element after being reflected by the third reflection surface and the fourth reflection surface in sequence after changing its polarization state by the second polarization unit.

[0016] Optionally, the reflection prism is provided with a first side surface, a second side surface, a third side surface, and a fourth side surface. A first reflection film is plated on the first side surface to form the first reflection surface, a second reflection film is plated on the second side surface to form the second reflection surface, a third reflection film is plated on the third side surface to form the third reflection surface, a fourth reflection film is plated on the fourth side surface to form the fourth reflection surface, and the fourth side surface and the second side surface are located on the same end surface.

[0017] Optionally, the circulator further includes a lens, which is used to collimate the first incident light and the second incident light and then transmit them to the beam splitting / combining element, and is also used to converge the light beam transmitted by the beam splitting / combining element and then transmit it to the corresponding optical fiber.

[0018] Optionally, the circulator further includes a stage, and the first optical fiber, the second optical fiber, and the third optical fiber are evenly spaced and arranged on the stage along a direction perpendicular to the incident light of the lens, and the lens is arranged between the stage and the beam splitting / combining element.

[0019] The present invention also discloses an optical module, which includes the circulator as described above.

[0020] Compared with the prior art, the beneficial effects of the circulator provided by the embodiment of the present utility model are as follows: The circulator of the embodiment of the present utility model is provided with a first optical fiber, a second optical fiber, a third optical fiber, a light splitting / combining element, a first polarization unit, a second polarization unit, a third polarization unit and a reflection unit. The first optical fiber, the second optical fiber and the third optical fiber can serve as three ports of the circulator and are respectively connected to external components. The first polarization unit, the second polarization unit and the third polarization unit can change the polarization state of the o-ray or e-ray, change the polarization state of the o-ray or e-ray before entering the reflection unit or change the polarization state of the o-ray or e-ray reflected by the reflection unit, so as to cooperate with the reflection unit for realizing light reflection and the light splitting / combining element for realizing light splitting and combining to realize the transmission of optical signals between different optical fibers. Among them, in the transmission directions of the first incident light and the second incident light, the same light splitting / combining element is used for input and output. Compared with the circulator solution, the devices used in the present application are fewer and the size is shorter, which is beneficial to the miniaturization of the overall circulator and can be applicable to the use scenario where all three ports are on the same side. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The technical solution of the present utility model will be further described in detail below in conjunction with the drawings and embodiments. In the drawings:

[0022] Figure 1 is a schematic structural diagram of a prior art circulator;

[0023] Figure 2 is a top view structural diagram of the circulator provided by the embodiment of the present utility model;

[0024] Figure 3 is a side view structural diagram of the circulator (omitting the second optical fiber and the third optical fiber) provided by the embodiment of the present utility model;

[0025] Figure 4 is a side view structural diagram of the circulator (omitting the first optical fiber and the third optical fiber, and the state of light output from the second optical fiber) provided by the embodiment of the present utility model;

[0026] Figure 5 is a side view structural diagram of the circulator (omitting the first optical fiber and the third optical fiber, and the state of light input from the second optical fiber) provided by the embodiment of the present utility model;

[0027] Figure 6 is a side view structural diagram of the circulator (omitting the first optical fiber and the second optical fiber) provided by the embodiment of the present utility model.

[0028] The reference numerals in the figures are as follows:

[0029] 110. First lens; 120. First polarization beam splitter; 130. First optical rotation unit; 140. Second polarization beam splitter; 150. Second optical rotation unit; 160. Third polarization beam splitter; 170. Second lens; 180. First optical fiber; 190. Second optical fiber; 200. Third optical fiber;

[0030] 210. First optical fiber; 220. Second optical fiber; 230. Third optical fiber; 240. Beam combining and splitting element; 241. Birefringent crystal; 250. First polarization unit; 251. First half-wave plate; 260. Second polarization unit; 261. Second half-wave plate; 262. Third half-wave plate; 263. Optical rotation plate; 270. Third polarization unit; 271. Fourth half-wave plate; 280. Reflection unit; 281. Reflection prism; 2811. First reflection surface; 2812. Second reflection surface; 2813. Third reflection surface; 2814. Fourth reflection surface; 290. Lens; 310. Stage. Detailed implementation mode

[0031] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention will be described in detail.

[0032] An embodiment of the present invention provides a circulator, as Figure 2 shown, the circulator includes a first optical fiber 210, a second optical fiber 220, a third optical fiber 230, a beam combining and splitting element 240, a first polarization unit 250, a second polarization unit 260, a third polarization unit 270, and a reflection unit 280. The first optical fiber 210, the second optical fiber 220, and the third optical fiber 230 can serve as three ports of the circulator and are respectively connected to external components. The first polarization unit 250, the second polarization unit 260, and the third polarization unit 270 can change the polarization state of the o-ray or e-ray. The reflection unit 280 can achieve the reflection of light.

[0033] Among them, the first incident light incident from the first optical fiber 210 is split by the beam combining and splitting element 240 into the o-ray and the e-ray. The e-ray is incident on the reflection unit 280 and is reflected by the reflection unit 280 into the second polarization unit 260 to change the polarization state and then transmitted to the beam combining and splitting element 240. The o-ray is changed in polarization state by the first polarization unit 250 and converted into the e-ray and incident on the reflection unit 280. After being reflected by the reflection unit 280 and entering the second polarization unit 260 to change the polarization state and converted into the o-ray, it is transmitted to the beam combining and splitting element 240. The beam combining and splitting element 240 combines the o-ray and the e-ray and outputs them through the second optical fiber 220.

[0034] The second incident light incident from the second optical fiber 220 is split by the optical combiner / splitter element 240 into an o-ray and an e-ray. The e-ray is incident on the second polarization unit 260, where its polarization state is changed to an o-ray and then it is incident on the reflection unit 280. After being reflected by the reflection unit 280, it enters the third polarization unit 270. After its polarization state is changed by the third polarization unit 270 to an e-ray, it is transmitted to the optical combiner / splitter element 240. The o-ray output by splitting is incident on the second polarization unit 260 after its polarization state is changed, then it is incident on the reflection unit 280 after being reflected by the reflection unit 280, and then enters the optical combiner / splitter element 240. The optical combiner / splitter element 240 combines the o-ray and the e-ray and outputs them through the third optical fiber 230.

[0035] As can be seen from the above, the circulator of the embodiment of the present invention realizes the transmission of optical signals between different optical fibers by arranging the first optical fiber 210, the second optical fiber 220, the third optical fiber 230, the optical combiner / splitter element 240, the first polarization unit 250, the second polarization unit 260, the third polarization unit 270 and the reflection unit 280. The first optical fiber 210, the second optical fiber 220 and the third optical fiber 230 can serve as the three ports of the circulator and are respectively connected to external components. The first polarization unit 250, the second polarization unit 260 and the third polarization unit 270 can change the polarization state of the o-ray or the e-ray, change the polarization state of the o-ray or the e-ray before it is incident on the reflection unit 280, or change the polarization state of the o-ray or the e-ray after being reflected by the reflection unit 280. Thus, in cooperation with the reflection unit 280 that realizes optical reflection and the optical combiner / splitter element 240 that realizes optical combination and splitting, the transmission of optical signals between different optical fibers is achieved. Among them, in the transmission direction of the first incident light and the second incident light, the same optical combiner / splitter element 240 is used for input and output. Compared with the circulator solution, the devices used in this application are fewer and the size is shorter, which is beneficial to the miniaturization of the overall circulator and can be applied to the usage scenario where all three ports are on the same side.

[0036] Among them, the o-ray and the e-ray are two types of polarized light. The o-ray represents the ordinary ray, and the e-ray represents the extraordinary ray.

[0037] The circulator of the embodiment of the present invention is a reflection-type circulator, which can not only realize the functions of an ordinary circulator but also realize the functions of a reflection-type circulator.

[0038] In an alternative embodiment of the present application, the optical combiner / splitter element 240 uses a birefringent crystal 241, which can split the incident natural light into an o-ray and an e-ray, or combine the o-ray and the e-ray into natural light. The birefringent crystal 241 is also called a birefringent material, which is a crystal with different refractive indices. This difference depends on the direction in which the light passes through the material. In this material, the incident light is split into two beams: the ordinary beam (o-ray) and the extraordinary beam (e-ray). These two beams of light propagate at different speeds in the crystal and usually have different polarization states.

[0039] Reference Figure 2 and Figure 3 The first polarization unit 250 includes a first half-wave plate 251. The o-light split and output by the beam splitter / combiner element 240 is incident on the reflection unit 280 after its polarization state is changed to e-light through the first half-wave plate 251.

[0040] The half-wave plate is a birefringent crystal 241 with a certain thickness. When light incident normally passes through it, the phase difference between the ordinary light (o-light) and the extraordinary light (e-light) is equal to π or an odd multiple of it. Compared with other polarization elements, the half-wave plate does not cause loss of light intensity when adjusting the polarization state of light. Its structure is simple, easy to use, and can be easily integrated into various optical systems.

[0041] By setting the first half-wave plate 251 as the first polarization unit 250, the polarization state of the o-light split and output by the beam splitter / combiner element 240 can be changed, rotating the o-light by 90 degrees and converting it into e-light. The converted e-light is transmitted to the reflection unit 280.

[0042] Reference Figure 2 and Figure 4 The second polarization unit 260 includes a second half-wave plate 261, a third half-wave plate 262, and an optical rotator 263. The second half-wave plate 261 and the third half-wave plate 262 are located on the same side of the optical rotator 263, and the first half-wave plate 251 and the second half-wave plate 261 are arranged side by side in a first direction, and the second half-wave plate 261 and the third half-wave plate 262 are arranged side by side in a second direction. The first direction and the second direction are perpendicular to each other and both perpendicular to the direction of the light output by the beam splitter / combiner element 240. The first direction is the x-direction as shown in Figure 2 and the second direction is the y-direction as shown in Figure 2-5 .

[0043] Among them, in the transmission direction of the first incident light, the split and output e-light is incident on the reflection unit 280, and after being reflected by the reflection unit 280, it passes through the optical rotator 263 and the second half-wave plate 261 in sequence, and after the polarization state is changed, it is transmitted to the beam splitter / combiner element 240. The split and output o-light is incident on the reflection unit 280 after its polarization state is changed to e-light through the first half-wave plate 251, and after being reflected by the reflection unit 280, it passes through the optical rotator 263 and the third half-wave plate 262 in sequence, and after the polarization state is changed to o-light, it is transmitted to the beam splitter / combiner element 240.

[0044] In the transmission direction of the second incident light, the split and output o-light passes through the third half-wave plate 262 and the optical rotator 263 in sequence, and after the polarization state is changed, it is incident on the reflection unit 280. The split and output e-light passes through the second half-wave plate 261 and the optical rotator 263 in sequence, and after the polarization state is changed to o-light, it is incident on the reflection unit 280.

[0045] By arranging the first half-wave plate 251 and the second half-wave plate 261 side by side along the first direction, and arranging the second half-wave plate 261 and the third half-wave plate 262 side by side along the second direction, and reducing the distance between the first half-wave plate 251, the second half-wave plate 261 and the third half-wave plate 262, the overall length of the first polarization unit 250 and the second polarization unit 260 can be reduced, optimizing the space utilization rate of the components, making the structure between the devices more compact, achieving the change of the polarization state of e-light or o-light with a smaller volume, which is beneficial to the miniaturization of the overall circulator.

[0046] Further, referring to Figures 2 to 5 , the third polarization unit 270 includes a fourth half-wave plate 271. The first half-wave plate 251, the second half-wave plate 261 and the fourth half-wave plate 271 are arranged side by side in sequence along the first direction. In the transmission direction of the second incident light, the o-light output by beam splitting sequentially passes through the fourth half-wave plate 271 and the optical rotation plate 263, and after changing the polarization state, it is incident on the reflection unit 280. After being reflected by the reflection unit 280, it is incident on the fourth half-wave plate 271, and after changing the polarization state by the fourth half-wave plate 271 and being converted into e-light, it is incident on the beam combining / splitting element 240.

[0047] By using the fourth half-wave plate 271 as the third polarization unit 270, the polarization state of the o-light reflected by the reflection unit 280 can be changed, and the o-light can be converted into e-light. Combining the o-light reflected by the reflection unit 280 and entering the beam combining / splitting element 240, there is e-light and o-light transmitted to the beam combining / splitting element 240 for beam combining in the transmission direction of the second incident light.

[0048] And arranging the first half-wave plate 251, the second half-wave plate 261 and the fourth half-wave plate 271 side by side in sequence along the first direction, reducing the distance between the first half-wave plate 251, the second half-wave plate 261, the third half-wave plate 262 and the fourth half-wave plate 271, the first polarization unit 250, the second polarization unit 260 and the third polarization unit 270 located between the beam combining / splitting element 240 and the reflection unit 280 have a compact structure and occupy a smaller volume, making the overall size of the circulator shorter, which is more beneficial to the miniaturization of the circulator.

[0049] In the embodiment of the present application, the optical axis angles of the first half-wave plate 251 and the fourth half-wave plate 271 are both 45 degrees, the optical axis angles of the second half-wave plate 261 and the third half-wave plate 262 are both 22.5 degrees, and the optical rotation plate 263 is a 45-degree optical rotation plate 263.

[0050] The optical axis angles of the first half-wave plate 251 and the fourth half-wave plate 271 are both 45 degrees. Referring to Figure 3 and Figure 6 , when the light is transmitted from left to right, the polarization state rotates clockwise by 90 degrees; when the light is transmitted from right to left, the polarization state rotates clockwise by -90 degrees. Therefore, both can achieve the interchange of o-light and e-light.

[0051] The optical axis angle of the second half-wave plate 261 is 22.5 degrees. Refer to Figure 4 and Figure 5 , when light is transmitted from left to right, the polarization state rotates clockwise by 45 degrees; when light is transmitted from right to left, the polarization state rotates clockwise by -45 degrees. The optical axis angle of the third half-wave plate 262 is 22.5 degrees. Refer to Figure 4 and Figure 5 , when light is transmitted from left to right, the polarization state rotates clockwise by -45 degrees; when light is transmitted from right to left, the polarization state rotates clockwise by 45 degrees.

[0052] The optical rotation plate 263 uses a 45-degree optical rotation plate 263. Whether light is transmitted from left to right or from right to left, the polarization state rotates clockwise by 45 degrees.

[0053] Therefore, when the optical axis angles of the first half-wave plate 251 and the fourth half-wave plate 271 are both 45 degrees, the optical axis angles of the second half-wave plate 261 and the third half-wave plate 262 are both 22.5 degrees, and the optical rotation plate 263 is a 45-degree optical rotation plate 263, it can cooperate with the optical splitting / combining element 240 and the reflection unit 280 to enable the first incident light to be incident from the first optical fiber 210 and output through the second optical fiber 220, and the second incident light to be incident from the second optical fiber 220 and output through the third optical fiber 230.

[0054] In an alternative embodiment of the present application, refer to Figure 2 , the reflection unit 280 includes a reflection prism 281. The reflection prism 281 is provided with a first reflection surface 2811, a second reflection surface 2812, a third reflection surface 2813, and a fourth reflection surface 2814. In the transmission direction of the first incident light, the e-light output by beam splitting and the e-light output by the first polarization unit 250 are both reflected by the first reflection surface 2811 and the second reflection surface 2812 in sequence and then incident on the second polarization unit 260; in the transmission direction of the second incident light, the e-light output by beam splitting is incident on the second polarization unit 260, changes its polarization state to become o-light, and then is reflected by the third reflection surface 2813 and the fourth reflection surface 2814 in sequence and then incident on the third polarization unit 270. The o-light output by beam splitting is incident on the second polarization unit 260, changes its polarization state, and then is reflected by the third reflection surface 2813 and the fourth reflection surface 2814 in sequence and then incident on the optical splitting / combining element 240.

[0055] The reflecting prism 281 is an optical element used to change the propagation direction or imaging direction of light. By using the reflecting prism 281 as the reflection unit 280, the first reflecting surface 2811, the second reflecting surface 2812, the third reflecting surface 2813, and the fourth reflecting surface 2814 on the reflecting prism 281 are used to reflect light, so that the first incident light and the second incident light are finally reflected back to the beam splitting / combining element 240, realizing the reflection of light with different transmission paths by the same reflecting prism 281, using fewer devices and further reducing the size.

[0056] Furthermore, the reflecting prism 281 is provided with a first side surface, a second side surface, a third side surface, and a fourth side surface. A first reflecting film is deposited on the first side surface to form the first reflecting surface 2811, a second reflecting film is deposited on the second side surface to form the second reflecting surface 2812, a third reflecting film is deposited on the third side surface to form the third reflecting surface 2813, and a fourth reflecting film is deposited on the fourth side surface to form the fourth reflecting surface 2814, and the fourth side surface and the second side surface are located on the same end surface.

[0057] By forming the first reflecting surface 2811, the second reflecting surface 2812, the third reflecting surface 2813, and the fourth reflecting surface 2814 on the reflecting prism 281 in the form of coating, different film materials and film thicknesses can be selected according to different application requirements to achieve the best optical performance; the coating can protect the optical surface of the reflecting prism 281 from physical and chemical damage. For example, some reflecting films can provide a scratch-resistant, waterproof, or anti-corrosion protective layer, increasing the service life and stability of the optical element. Moreover, by directly coating the side surfaces of the reflecting prism 281, the optical design and assembly process can be simplified, the number of components can be reduced, and the size of the overall device can be reduced.

[0058] Reference Figures 2 to 5 In an optional embodiment of the present application, the circulator further includes a lens 290. The lens 290 is used to collimate the first incident light and the second incident light and then transmit them to the beam splitting / combining element 240, and is also used to converge the light beam transmitted by the beam splitting / combining element 240 and then transmit it to the corresponding optical fiber.

[0059] The lens 290 is a commonly used optical element mainly made of a transparent material (such as glass or plastic) and has at least one curved surface. The main function of the lens 290 is to change the propagation direction and focus of light by refracting light rays.

[0060] By setting the lens 290, the lens 290 can turn the first incident light and the second incident light into collimated light beams, transmit the collimated light beams to the beam splitter / combiner 240. The collimated light beams can maintain the consistency of their beam diameters and shapes over a long distance, can be more easily aligned to enter the beam splitter / combiner 240, and the collimation process helps to reduce the divergence of the light beam during transmission, which means that the light energy is more concentrated, the signal intensity is maintained, and the attenuation caused by scattering or beam divergence is reduced.

[0061] In the transmission direction of the first incident light, the lens 290 also converges the light beam output by the beam splitter / combiner 240 to the second optical fiber 220 and transmits it to the corresponding device through the second optical fiber 220. In the transmission direction of the second incident light, the lens 290 also converges the light beam output by the beam splitter / combiner 240 to the third optical fiber 230 and transmits it to the corresponding device through the third optical fiber 230. Using the lens 290 to achieve the convergence of the light beam can focus the light beam on the entrance of the optical fiber, maximize the transmission of the optical signal, reduce the loss and reflection of light, ensure that more light energy is received by the optical fiber, and increase the efficiency of the optical signal entering the optical fiber.

[0062] Reference Figures 2 to 5 Referring to

[0063] In an optional embodiment of the present application, the circulator further includes a carrier 310. The first optical fiber 210, the second optical fiber 220, and the third optical fiber 230 are evenly spaced and arranged on the carrier 310 in a direction perpendicular to the incident light of the lens 290, and the lens 290 is arranged between the carrier 310 and the beam splitter / combiner 240.

[0064] By setting the carrier 310, the carrier 310 provides physical support for the first optical fiber 210, the second optical fiber 220, and the third optical fiber 230, can prevent optical misalignment caused by vibration or external interference, and improve the stability of each optical fiber during operation and use; the carrier 310 can facilitate the precise alignment of the optical fiber with other optical devices, optimize the transmission of light and reduce signal loss. In addition, the carrier 310 can also be designed to have a thermal management function to help dissipate heat and prevent the optical fiber from degrading or being damaged due to overheating.

[0064] During specific operation, the first optical fiber 210, the second optical fiber 220, and the third optical fiber 230 can be adhesively bonded to the carrier 310 with glue, which is convenient for assembly.

[0065] Reference Figure 3 and Figure 4 , Figure 3 and Figure 4 The arrow directions in

[0066] (1) The first optical fiber 210 inputs the first incident light, and the first incident light becomes a collimated light beam after passing through the lens 290;

[0067] (2) After the collimated light beam passes through the beam splitter / combiner element 240, it is divided into an o-ray and an e-ray;

[0068] (3) After the o-ray passes through the first half-wave plate 251, it rotates 90 degrees and becomes an e-ray; the e-ray output by splitting does not pass through the first half-wave plate 251 and remains an e-ray unchanged;

[0069] (4) After the two e-rays pass through the reflection prism 281, they keep transmitting through the film layer on the reflection prism 281, that is, both of the two e-rays are partially reflected, partially absorbed, and there is also a part that can transmit through;

[0070] (5) Figure 3 、 4 For the e-ray represented by the dotted line in

[0071] (6) Figure 3 、 4 For the e-ray represented by the solid line in

[0072] (7) After the e-ray and the o-ray pass through the beam splitter / combiner element 240, they are combined into natural light and input to the lens 290;

[0073] (8) The light after passing through the lens 290, the collimated light beam converges and exits from the second optical fiber 220.

[0074] Refer to Figure 5 and Figure 6 , Figure 5 and Figure 6 The arrow directions in

[0075] (1) The second optical fiber 220 inputs the second incident light, and it becomes a collimated light beam after passing through the lens 290;

[0076] (2) After the collimated light beam passes through the beam splitter / combiner element 240, the natural light is divided into an o-ray and an e-ray;

[0077] (3) The e-light output by beam splitting rotates 45 degrees clockwise after passing through the second half-wave plate 261; then passes through the optical rotation plate 263 and rotates 45 degrees clockwise again; the cumulative rotation is 45 + 45 = 90 degrees, and the e-light is converted into o-light.

[0078] (4) The o-light output by beam splitting rotates -45 degrees clockwise after passing through the third half-wave plate 262; then passes through the optical rotation plate 263 and rotates 45 degrees clockwise again; the cumulative rotation is 45 - 45 = 0 degrees, and the o-light remains unchanged.

[0079] (5) The two beams of o-light are reflected by the film layer after passing through the reflection prism 281.

[0080] (6) Figure 5 、 6 The o-light represented by the dotted line in

[0081] (9) Figure 5 、 6 passes from right to left through the fourth half-wave plate 271 and rotates -90 degrees clockwise, and the o-light is converted into e-light; the e-light represented by the solid line in

[0082] (7) The e-light and o-light pass through the beam combining and splitting element 240 and are combined into natural light and input to the lens 290.

[0083] (8) The light after passing through the lens 290 converges the collimated light beam and exits from the third optical fiber 230.

[0084] The embodiment of the present utility model also provides a preferred embodiment of an optical module. The optical module includes the above-mentioned circulator. In the optical module of the embodiment of the present utility model, the circulator is provided with the first optical fiber 210, the second optical fiber 220, the third optical fiber 230, the beam combining and splitting element 240, the first polarization unit 250, the second polarization unit 260, the third polarization unit 270 and the reflection unit 280. The first optical fiber 210, the second optical fiber 220 and the third optical fiber 230 can be used as the three ports of the circulator and are respectively connected to external components. The first polarization unit 250, the second polarization unit 260 and the third polarization unit 270 can change the polarization state of o-light or e-light, change the polarization state of o-light or e-light before entering the reflection unit 280 or change the polarization state of o-light or e-light after being reflected by the reflection unit 280, so as to cooperate with the reflection unit 280 that realizes light reflection and the beam combining and splitting element 240 that realizes beam combining and splitting to realize the transmission of optical signals between different optical fibers. Among them, in the transmission directions of the first incident light and the second incident light, the same beam combining and splitting element 240 is used for input and output. Compared with the circulator scheme, the devices used in this application are fewer and the size is shorter, which is beneficial to the miniaturization of the overall circulator and can be applied to the use scenario where all three ports are on the same side.

[0085] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. For those skilled in the art, the technical solutions recorded in the above embodiments can be modified, or some of the technical features can be equivalently replaced; and all such modifications and replacements should fall within the protection scope of the appended claims of the present invention.

Claims

1. A circulator, characterized in that, It includes a first optical fiber, a second optical fiber, a third optical fiber, a beam splitting / combining element, a first polarization unit, a second polarization unit, a third polarization unit, and a reflection unit. Among them, The first incident light incident from the first optical fiber is split by the beam splitting / combining element into an o-ray and an e-ray. The e-ray is incident on the reflection unit, reflected by the reflection unit, enters the second polarization unit, changes its polarization state, and then is transmitted to the beam splitting / combining element. The o-ray is changed in polarization state by the first polarization unit to be converted into an e-ray, incident on the reflection unit, reflected by the reflection unit, enters the second polarization unit, changes its polarization state to be converted into an o-ray, and then is transmitted to the beam splitting / combining element. The beam splitting / combining element combines the o-ray and the e-ray and outputs them through the second optical fiber. The second incident light incident from the second optical fiber is split by the beam splitting / combining element into an o-ray and an e-ray. The e-ray is incident on the second polarization unit, changes its polarization state to be converted into an o-ray, then is incident on the reflection unit, reflected by the reflection unit, enters the third polarization unit, changes its polarization state to be converted into an e-ray by the third polarization unit, and then is transmitted to the beam splitting / combining element. The o-ray output by splitting is changed in polarization state by the second polarization unit, then is incident on the reflection unit, reflected by the reflection unit, and enters the beam splitting / combining element. The beam splitting / combining element combines the o-ray and the e-ray and outputs them through the third optical fiber.

2. The circulator according to claim 1, characterized in that, The first polarization unit includes a first half-wave plate. The o-ray output by splitting by the beam splitting / combining element is changed in polarization state by the first half-wave plate to be converted into an e-ray and then is incident on the reflection unit.

3. The circulator according to claim 2, characterized in that, The second polarization unit includes a second half-wave plate, a third half-wave plate, and a rotatory polarization plate. The second half-wave plate and the third half-wave plate are on the same side of the rotatory polarization plate, and the first half-wave plate and the second half-wave plate are arranged side by side and attached along a first direction. The second half-wave plate and the third half-wave plate are arranged side by side and attached along a second direction. The first direction and the second direction are perpendicular to each other and both are perpendicular to the direction of the light output by the beam splitting / combining element. In the transmission direction of the first incident light, the e-ray output by splitting is incident on the reflection unit, reflected by the reflection unit, and then passes through the rotatory polarization plate and the second half-wave plate in sequence, changes its polarization state, and is transmitted to the beam splitting / combining element. The o-ray output by splitting is changed in polarization state by the first half-wave plate to be converted into an e-ray, incident on the reflection unit, reflected by the reflection unit, and then passes through the rotatory polarization plate and the third half-wave plate in sequence, changes its polarization state to be converted into an o-ray, and is transmitted to the beam splitting / combining element. In the transmission direction of the second incident light, the o-ray output by splitting passes through the third half-wave plate and the rotatory polarization plate in sequence, changes its polarization state, and is incident on the reflection unit. The e-ray output by splitting passes through the second half-wave plate and the rotatory polarization plate in sequence, changes its polarization state to be converted into an o-ray, and is incident on the reflection unit.

4. The circulator according to claim 3, characterized in that, The third polarization unit includes a fourth half-wave plate. The first half-wave plate, the second half-wave plate, and the fourth half-wave plate are sequentially arranged side by side in a first direction. In the transmission direction of the second incident light, the o-light output by beam splitting sequentially passes through the fourth half-wave plate and the optical rotation plate, and after changing the polarization state, it is incident on the reflection unit. After being reflected by the reflection unit, it is incident on the fourth half-wave plate. After passing through the fourth half-wave plate and changing the polarization state to be converted into e-light, it is incident on the beam splitting / combining element.

5. The circulator according to claim 4, characterized in that, The optical axis angles of the first half-wave plate and the fourth half-wave plate are both 45 degrees, the optical axis angles of the second half-wave plate and the third half-wave plate are both 22.5 degrees, and the optical rotation plate is a 45-degree optical rotation plate.

6. The circulator according to claim 1, wherein, The reflection unit includes a reflection prism. The reflection prism is provided with a first reflection surface, a second reflection surface, a third reflection surface, and a fourth reflection surface. In the transmission direction of the first incident light, the e-light output by beam splitting and the e-light output by the first polarization unit both sequentially pass through the first reflection surface and the second reflection surface and are reflected and then incident on the second polarization unit; in the transmission direction of the second incident light, the e-light output by beam splitting is incident on the second polarization unit, changes the polarization state to be converted into o-light, and then sequentially passes through the third reflection surface and the fourth reflection surface and is reflected and then incident on the third polarization unit. The o-light output by beam splitting passes through the second polarization unit, changes the polarization state, and then sequentially passes through the third reflection surface and the fourth reflection surface and is reflected and then incident on the beam splitting / combining element.

7. The circulator according to claim 6, characterized in that, The reflection prism is provided with a first side surface, a second side surface, a third side surface, and a fourth side surface. A first reflection film is plated on the first side surface to form the first reflection surface, a second reflection film is plated on the second side surface to form the second reflection surface, a third reflection film is plated on the third side surface to form the third reflection surface, a fourth reflection film is plated on the fourth side surface to form the fourth reflection surface, and the fourth side surface and the second side surface are located on the same end surface.

8. The circulator according to any one of claims 1-7, characterized in that, The circulator further includes a lens. The lens is used to collimate the first incident light and the second incident light and then transmit them to the beam splitting / combining element, and is also used to converge the light beam transmitted by the beam splitting / combining element and then transmit it to the corresponding optical fiber.

9. The circulator according to claim 8, wherein, The circulator further includes a stage. The first optical fiber, the second optical fiber, and the third optical fiber are uniformly spaced and arranged on the stage in a direction perpendicular to the incident light of the lens. The lens is arranged between the stage and the beam splitting / combining element.

10. An optical module, characterized in that, It includes the circulator according to any one of claims 1-9.

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