Easily-processed miniaturized two-stage isolation optical circulator

Abstract

The utility model relates to a miniaturized two-stage isolation optical circulator easy to process. The miniaturized two-stage isolation optical circulator comprises a first collimator, a second collimator, an optical circulator core, a first reflector plate, a second reflector plate, a circulator core base and a magnet, the optical circulator core comprises a first polarization splitting prism, a half-wave plate, a Faraday rotation plate and a second polarization splitting prism; the first collimator collimates the output light of the Port1 port into parallel light, and couples the output light of the Port2 port to the Port3 port for receiving after passing through the optical circulator core; the second collimator couples the light output by the Port1 port to the Port2 port for receiving after passing through the optical circulator core, and collimates the light output by the Port2 port into parallel light, and the first reflector plate and the second reflector plate reflect the optical signal back to the optical circulator core. According to the utility model, the processing difficulty of the optical circulator can be obviously reduced, the production efficiency is improved, and the production cost is reduced; while high isolation is realized, dependence on processing precision is reduced, so that yield and consistency of products are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical communication and optical device field especially an easy processing miniaturized double -stage isolation optical circulator. BACKGROUND

[0002] Optical circulator is a vital element in optical communication system, it can ensure the unidirectional transmission of optical signal between different ports, thereby effectively preventing the interference of reverse optical signal to light source or other optical devices. In optical communication system, optical circulator not only needs to have good isolation, but also requires to maintain stable performance while reducing the loss as much as possible. In many optical circulator designs, double -stage isolation structure is concerned by more designers because it can realize higher isolation.

[0003] The existing double -stage isolation optical circulator usually adopts three -port optical circulator structure, wherein one or two exit surfaces are plated with high reflection film, so that the optical signal is transmitted twice in the optical circulator, thereby realizing the double -stage isolation effect of reverse optical transmission. The isolation degree of this scheme can generally reach more than 60dB at the center wavelength of design, which can effectively improve the signal quality of optical communication system and reduce the influence of internal noise on the system. However, this design also has several obvious defects.

[0004] Firstly, the plating of high reflection film requires extremely high processing precision, especially in the production process, the uniformity, reflectivity and flatness of high reflection film layer all have important influence on the final performance of optical circulator. In order to ensure the quality of high reflection film, high -precision optical processing equipment is usually needed, which makes the production process complex and expensive. For large -scale production, this design not only increases the equipment investment, but also greatly increases the production cost.

[0005] Secondly, there is a certain error in the processing of high reflection film, which will directly affect the performance of optical circulator. For example, the thickness and uniformity difference of reflection film will cause the deviation of light beam in the transmission process, and then affect the isolation performance of optical circulator, and even may cause unstable isolation. In addition, in the process of processing and assembling of optical circulator, the tolerance error of other optical elements (such as the installation angle error of collimator, the error of internal elements of optical circulator, etc.) will also affect the final performance of optical circulator. Although these errors can be controlled by accurate calculation in design, but in actual production, these errors are inevitable, and because the precision requirement of high reflection film is too high, once a small processing error occurs, the performance of optical circulator may be seriously reduced, or even cannot work normally.

[0006] The existence of these problems makes the design of high-reflective film-coated optical circulators face many challenges in production and use. For example, factors such as batch differences, equipment wear and tear, material problems that may occur during production can all affect the quality of the high-reflective film, leading to fluctuations in the performance of the optical circulator and affecting the stability and reliability of the system. In addition, due to minor errors in the production process, the yield of the optical circulator is usually low, making it difficult to ensure high-quality output for large-scale production.

[0007] To solve this problem, some researchers have tried to use other materials or techniques to improve the design of the optical circulator. For example, adjusting the optical path or using new coating techniques to reduce the requirement for processing precision. However, these solutions either still require high processing precision or do not significantly reduce costs, resulting in their not being widely used in actual production. Therefore, how to design a new optical circulator structure that can maintain high isolation while significantly reducing processing difficulty and production cost has become an important direction for current optical circulator research. Practical new type content

[0008] Therefore, the purpose of the present application is to provide an easy-to-process miniaturized two-stage isolation optical circulator that can achieve high isolation while reducing processing precision, reducing production cost and improving production efficiency.

[0009] The present application adopts the following scheme: an easy-to-process miniaturized two-stage isolation optical circulator, comprising a first collimator, a second collimator, an optical circulator core, a first reflecting sheet, a second reflecting sheet, a circulator core base and a magnet; the optical circulator core comprises a first polarization beam splitter prism, a half-wave plate, a Faraday rotator, and a second polarization beam splitter prism; the first collimator has a Port1 port and a Port3 port, and the second collimator has a Port2 port; the first collimator collimates the light output from the Port1 port into parallel light, and couples the light output from the Port2 port to the Port3 port after passing through the optical circulator core; the second collimator couples the light output from the Port1 port to the Port2 port after passing through the optical circulator core, and collimates the light output from the Port2 port into parallel light; the first reflecting sheet and the second reflecting sheet reflect the optical signal back to the optical circulator core.

[0010] Further, the cross section of the first polarization beam splitter prism is a parallelogram structure, and a first polarization beam splitter film is arranged inside the first polarization beam splitter prism.

[0011] Further, the right side of the cross section of the first polarization beam splitter prism is attached to the left side of the half-wave plate, and the first polarization beam splitter film is parallel to the upper and lower sides of the first polarization beam splitter prism.

[0012] Further, the second polarization beam splitting prism has a right-angled trapezoidal structure with a 45° base angle, and a second polarization beam splitting film is arranged in the second polarization beam splitting prism.

[0013] Further, the second polarization beam splitting prism has a right-angled trapezoidal structure with a 45° base angle, and a second polarization beam splitting film is arranged in the second polarization beam splitting prism.

[0014] Further, the half-wave plate and the Faraday rotator are combined into an integrated optical rotator for rotating the signal light in a single transmission direction by 90°.

[0015] Further, the first collimator is a double-fiber collimator.

[0016] Further, the collimated parallel light of the two ports of the first collimator has an included angle of 2α, and the two ports are symmetrical about the axis of the first collimator, the Port 1 port is horizontally upward by an angle of α, and the Port 3 port is horizontally downward by an angle of α.

[0017] Further, the second collimator is a single-fiber collimator.

[0018] Further, the first reflective sheet and the second reflective sheet are bonded on the circulator core base.

[0019] Compared with the prior art, the utility model has the advantages that the utility model discloses a small-sized two-stage isolation optical circulator which can significantly reduce the processing difficulty of the optical circulator, improve the production efficiency and reduce the production cost.

[0020] To make the purpose, technical scheme and advantages of the utility model clearer, the utility model will be further described in detail through specific embodiments and related drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a brief implementation structure front view of the optical circulator of the embodiment of the utility model;

[0022] Figure 2 It is a brief implementation structure side view of the optical circulator of the embodiment of the utility model;

[0023] Figure 3 It is a brief implementation structure schematic view of the optical circulator core of the embodiment of the utility model;

[0024] Figure 4 Figure 2 is a schematic diagram of light propagation from the Port1 port to the first reflecting sheet according to an embodiment of the present application;

[0025] Figure 5 Figure 2 is a schematic diagram of light propagation from the Port1 port to the first reflecting sheet according to an embodiment of the present application;

[0026] Figure 6 Figure 2 is a schematic diagram of light propagation from the Port1 port to the first reflecting sheet according to an embodiment of the present application;

[0027] Figure 7 Figure 2 is a schematic diagram of light propagation from the Port1 port to the first reflecting sheet according to an embodiment of the present application;

[0028] Figure 8 Figure 2 is a schematic diagram of light propagation from the Port1 port to the first reflecting sheet according to an embodiment of the present application;

[0029] Figure 9 Figure 2 is a schematic diagram of light propagation from the Port1 port to the first reflecting sheet according to an embodiment of the present application;

[0030] Figure 10 Figure 2 is a schematic diagram of light propagation from the Port1 port to the first reflecting sheet according to an embodiment of the present application;

[0031] Figure 2 is a schematic diagram of light propagation from the Port1 port to the first reflecting sheet according to an embodiment of the present application;

[0032] In all the drawings, the same reference signs refer to the same technical features, specifically:

[0033] The bidirectional short arrow mark represents the P light polarization state, and the dot represents the S light polarization state. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0035] It is to be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments consistent with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0036] As shown in Figures 1-10 A small-sized and easy-to-process two-stage isolated optical circulator includes a first collimator 101, a second collimator 102, an optical circulator core 103, a first reflective sheet 104, a second reflective sheet 105, a circulator core base 106, and a magnet 107. The optical circulator core includes a first polarization beam splitter 301, a half-wave plate 302, a Faraday rotator 303, and a second polarization beam splitter 304. The half-wave plate 302 and the Faraday rotator 303 are located between the first polarization beam splitter 301 and the second polarization beam splitter 304. Signal ports Port1, Port2, and Port3 are located on the left side of the first polarization beam splitter. The first collimator 101 has a Port1 port and a Port3 port. The second collimator 102 has a Port2 port. The first collimator 101 collimates the light output from the Port1 port into parallel light and couples the light output from the Port2 port to the Port3 port after passing through the optical circulator core 103. The second collimator 102 couples the light output from the Port1 port to the Port2 port after passing through the optical circulator core 103 and collimates the light output from the Port2 port into parallel light. The first reflective sheet 104 and the second reflective sheet 105 reflect the optical signal back to the optical circulator core 103.

[0037] The first polarization beam splitter and the second polarization beam splitter are used for inputting or outputting signal light. The first polarization beam splitter and the second polarization beam splitter are used for separating or synthesizing P-polarized light and S-polarized light in the signal light.

[0038] By combining the light output crossing angle of the double-fiber collimator and the adjustable reflective sheet, the transmission path of the optical path is optimized, realizing a compact and small two-stage isolated structure. This design can significantly reduce the processing difficulty of the optical circulator, improve the production efficiency, and reduce the production cost. Compared with the prior art, the present application reduces the dependence on processing precision while achieving high isolation, thereby improving the yield and consistency of the product. It overcomes the various drawbacks in the design of traditional high-reflection films, realizing the organic combination of high performance and low production cost of the optical circulator. The present application has wide application prospects, especially in the fields of optical communication, fiber sensing, and other fields that require high isolation and low insertion loss.

[0039] In the embodiment, the first polarization beam splitting prism 301 has a parallelogram structure in cross section, and a first polarization beam splitting film 3011 is arranged inside the prism.

[0040] In the embodiment, the right side of the cross section of the first polarization beam splitting prism 301 is attached to the left side of the half-wave plate, and the first polarization beam splitting film 3011 is parallel to the upper and lower sides of the first polarization beam splitting prism 301.

[0041] In the embodiment, the second polarization beam splitting prism 304 has a right-angled trapezoid structure with a bottom angle of 45° in cross section, and a second polarization beam splitting film 3012 is arranged inside the prism.

[0042] In the embodiment, the long bottom side of the cross section of the second polarization beam splitting prism 304 is attached to the right side of the Faraday rotator, the side with the right angle waist of the cross section of the second polarization beam splitting prism 304 faces downward, and the side with the oblique waist faces upward, and the second polarization beam splitting film 3012 is parallel to the upper side of the second polarization beam splitting prism. The first reflecting plate is located beside the side with the right angle of the cross section of the second polarization beam splitting prism 304, i.e., the right side, and the second reflecting plate is located beside the side with the right angle waist of the cross section of the second polarization beam splitting prism 304, i.e., the lower side.

[0043] In the embodiment, the half-wave plate 302 and the Faraday rotator 303 are attached to form an optical rotation mechanism, which is used to rotate the polarization direction of the signal light in one transmission direction by 90°, and does not rotate the polarization direction of the signal light in the other transmission direction, i.e., when the light propagates from left to right, the polarization direction is rotated by 90°, and when the light propagates from right to left, the polarization direction is not rotated; in the specific implementation process, the positions of the half-wave plate and the Faraday rotator can be interchanged.

[0044] In the embodiment, the first collimator 101 is a double-fiber collimator.

[0045] In the embodiment, the included angles of the collimated parallel light of the two ports Port1 and Port3 of the first collimator 101 are 2α, and the two ports are symmetrical about the axis of the first collimator 101, the Port1 port is horizontally upward by α angle, and the Port3 port is horizontally downward by α angle.

[0046] In the embodiment, the second collimator 102 is a single-fiber collimator.

[0047] In the embodiment, the first reflecting plate and the second reflecting plate are bonded to the circulator core base, the first and second reflecting plates can be adjusted in angle, and after the angle is adjusted, the first and second reflecting plates are bonded to the circulator core base, and the initial design rotation angle is denoted as β.

[0048] In the embodiment, all the attached surfaces and signal output surfaces are provided with anti-reflection films, and the angle of the signal light entering the circulator core is 1-4°.

[0049] like Figure 5 As shown, signal light enters the first polarizing beam splitter 301 from signal port Port1. After being transmitted to the first polarizing beam splitter 3011, the P-beam in the signal light is transmitted, and the S-beam is reflected. The S-beam is reflected by the lower end surface of the first polarizing beam splitter 301. After the P-beam and S-beam pass through the half-wave plate 302 and the Faraday rotator plate 303 respectively, their polarization directions change. The original P-beam becomes the S-beam, and the original S-beam becomes the P-beam. The rotated P-beam enters the second polarizing beam splitter 304 and passes through the second polarizing beam splitter 3012; the rotated S-beam enters the second polarizing beam splitter 304, is reflected by the upper end surface of the second polarizing beam splitter 304, and is then reflected by the second polarizing beam splitter 3012. The P-beam and S-beam are combined and transmitted to the first reflector 104 on the right side of the second polarizing beam splitter 304. Figure 6 As shown, after the signal light is reflected by the first reflector 104, it is transmitted back to the second polarizing beam splitter 304. After passing through the second polarizing beam splitter 3012, the P-beam in the signal light is transmitted, and the S-beam is reflected. The S-beam is reflected by the upper surface of the second polarizing beam splitter 304. After the P-beam and S-beam pass through the Faraday rotator 303 and the half-wave plate 302 respectively, their polarization directions remain unchanged. The P-beam enters the first polarizing beam splitter 301, is reflected by the lower surface of the first polarizing beam splitter 301, and is transmitted by the first polarizing beam splitter 3011. The S-beam enters the first polarizing beam splitter 301, is reflected by the first polarizing beam splitter 3011, and the two beams are combined and transmitted. After being reflected by the upper surface of the first polarizing beam splitter 301, they are transmitted to the signal port Port2.

[0050] like Figure 7 As shown, after the signal light exits from signal port Port2, it is transmitted to the first polarizing beam splitter 301. After being reflected by the upper surface of the first polarizing beam splitter 301, it is transmitted to the first polarizing beam splitting film 3011. The P-beam in the signal light is transmitted, and the S-beam is reflected. The P-beam is reflected by the lower surface of the first polarizing beam splitter 301. After the P-beam and S-beam pass through the half-wave plate 302 and the Faraday rotator plate 303 respectively, their polarization directions change; the original P-beam becomes S-beam, and the original S-beam becomes P-beam. The rotated P-beam enters the second polarizing beam splitter 304, is reflected by the upper surface of the second polarizing beam splitter, and then passes through the second polarizing beam splitting film 3012. The rotated S-beam enters the second polarizing beam splitter 304, is reflected by the second polarizing beam splitting film 3012, and the P-beam and S-beam are combined and transmitted to the second reflector 105 on the lower side of the second polarizing beam splitter 304. Figure 8As shown, the signal light is transmitted back to the second polarization beam splitting prism 304 after being reflected by the second reflecting sheet 105, and then to the second polarization beam splitting film 3012. The P light in the signal light is transmitted, and the S light is reflected. The P light is reflected by the upper end face of the second polarization beam splitting prism 304. After the P light and the S light pass through the Faraday rotator 303 and the half-wave plate 302 respectively, the polarization directions of the two do not change. The P light is transmitted by the first polarization beam splitting film 3011 after being incident into the first polarization beam splitting prism 301. The S light is reflected by the first polarization beam splitting film 3011 after being incident into the first polarization beam splitting prism 301 and being reflected by the lower end face of the first polarization beam splitting prism. The two are combined and transmitted to the signal port Port3.

[0051] Please refer to Figure 9 As shown in the light transmission angle diagram, the angle between the light out of the Port1 port and the horizontal direction is α. The relationship between the refraction angle A of the light after entering the optical circulator core and α is n1sinα=n2sinA, wherein n1 is the air refractive index, and n2 is the refractive index of the polarization beam splitting prism material of the optical circulator core. When the light is transmitted out of the optical circulator along the light path, the angle between the outcoming light and the horizontal direction is α. At this time, the angle between the reflected light after being incident to the first reflecting sheet and the horizontal direction is B, and the angle between the left side surface of the first reflecting sheet and the vertical direction is the rotation angle β1. The relationship between B and the rotation angle β1 of the first reflecting sheet is B=α-2β1. After the light is reflected by the first reflecting sheet, the light is transmitted back to the optical circulator core. The relationship between the refraction angle C of the light after entering the optical circulator core and B is n1sinB=n2sinC. Finally, the light is out of the optical circulator core with an angle B with the horizontal direction and reaches the Port2 port. Please refer to Figure 10 As shown in the light transmission angle diagram, the angle between the light out of the Port2 port and the horizontal direction is B. The refraction angle of the light after entering the optical circulator core is C. Further, the refraction angle of the light out of the optical circulator core is B. The angle between the upper side surface of the second reflecting sheet and the horizontal direction is the rotation angle β2. In order to ensure that the light returned from the second reflecting sheet can be correctly transmitted to the Port3 port, the relationship between the rotation angle β2 of the second reflecting sheet and the α angle is α=B+2β2. When the machining tolerance or assembly error occurs, it will usually cause the outcoming angle 2α of the double-fiber collimator to change. At this time, according to the above analysis, the insertion loss between the ports can be adjusted only by adjusting the angles β1 and β2. Through the above design, the production difficulty of the optical circulator can be greatly reduced, the yield and consistency of the product can be improved, and the performance requirement of high isolation can be realized. With the development of optical communication, optical fiber sensing and other technologies, the present application has great market potential and can replace the traditional optical circulator design scheme in a wider application scenario.

[0052] The two-stage isolation optical circulator of the present application includes several key design elements. First, a rotatory mechanism using a wave plate and a Faraday rotator is used to achieve polarization rotation and polarization splitting of the optical signal. The optical signal is processed by the rotatory mechanism, and the polarization state is rotated and distributed to different channels. Then, the optical signal is reflected by an adjustable reflector behind the exit surface. Unlike the high-reflectivity film in existing designs, the angle and position of the reflector can be adjusted after production to optimize the optical path, thereby reducing the impact of processing errors on performance. Through this adjustment mechanism, each port of the optical circulator can be optimized for coupling by fine-tuning the position and angle of the reflector without relying on precise machining of the high-reflectivity film. For example, after the optical signal enters the optical circulator core from the input port, it is processed by the rotatory mechanism, reflected by the reflector, and guided back into the optical circulator core, and then transmitted to the common port after passing through the rotatory mechanism again. When the optical signal exits from the common port, it passes through the optical circulator core, is processed by the rotatory mechanism, is adjusted by another reflector, is guided back into the optical circulator core, and is finally transmitted to the receiving port.

[0053] Another technical advantage of the present application is the use of a combination of a double-fiber collimator and a single-fiber collimator. The two fiber ports of the double-fiber collimator form a certain intersection angle after emitting light, which is compensated by the angle of the reflector in the optical circulator, thereby optimizing the efficiency of optical path transmission. However, due to the intersection angle error of the double-fiber collimator and the angle error in the optical circulator core, the coupling effect may be poor in traditional designs, or even the light emitted from the input port may not be received by the receiving port. Through the design of the present application, the high-reflectivity surface is arranged outside and the optical path is adjusted by the reflector, which can compensate for various processing and assembly errors by adjusting the reflector without changing the assembly structure, ensuring that the coupling effect between the ports meets the expected requirements.

[0054] Unless otherwise stated, if the above-mentioned any technical solution of the present application discloses a numerical range, the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is only one of the many implementable values with more obvious technical effects or representative values. Due to the large number of values, it is impossible to enumerate them all, so the present application only discloses some values to illustrate the technical solutions of the present application, and the above-mentioned enumerated values should not constitute a limitation on the scope of protection of the present application.

[0055] If the utility model discloses or involves mutually fixed connecting parts or structural members, then, except for another declaration, fixed connection can be understood as: detachably fixed connection (for example, using bolt or screw connection), and also can be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by integral structure (for example, integrally formed by using casting process) (except for obviously unable to adopt integral forming process).

[0056] In addition, the terms used to represent the position relationship or shape in any of the technical solutions of the utility model disclosed above include the state or shape similar, similar or close to the above, except for another declaration.

[0057] Any component provided by the utility model can be assembled by a plurality of separate components, or can be a separate component manufactured by an integral forming process.

[0058] The above is only a preferred embodiment of the utility model, and is not intended to limit the utility model in other forms, and any skilled person in the art can modify or change the above disclosed technical content to obtain equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments without departing from the technical solution of the utility model, according to the technical essence of the utility model, still belongs to the protection scope of the technical solution of the utility model.

Claims

1. A miniaturized, easily manufactured, two-stage isolation optical circulator, characterized in that: It includes a first collimator, a second collimator, an optical circulator core, a first reflector, a second reflector, a circulator core base, and a magnet; the optical circulator core includes a first polarizing beam splitter, a half-wave plate, a Faraday rotator, and a second polarizing beam splitter. The first collimator has a Port1 port and a Port3 port, and the second collimator has a Port2 port. The first collimator collimates the output light from the Port1 port into parallel light and couples the output light from the Port2 port to the Port3 port for reception after passing through the optical circulator core. The second collimator couples the output light from the Port1 port to the Port2 port for reception after passing through the optical circulator core, and collimates the output light from the Port2 port into parallel light. The first reflector and the second reflector reflect the optical signal back to the optical circulator core.

2. The easily manufactured, miniaturized, two-stage isolation optical circulator according to claim 1, characterized in that: The first polarizing beam splitter has a parallelogram cross-section and a first polarizing beam splitting film inside.

3. The easily manufactured, miniaturized, dual-stage isolation optical circulator according to claim 2, characterized in that: The right side of the first polarizing beam splitter is attached to the left side of the half-wave plate, and the first polarizing beam splitter film is parallel to the upper and lower sides of the first polarizing beam splitter.

4. The easily manufactured, miniaturized, two-stage isolation optical circulator according to claim 1, characterized in that: The cross-section of the second polarizing beam splitter is a right trapezoidal structure with a base angle of 45°, and a second polarizing beam splitter film is provided inside it.

5. The easily manufactured, miniaturized, two-stage isolation optical circulator according to claim 4, characterized in that: The side of the long base of the second polarizing beam splitter is in contact with the right side of the Faraday rotator. The side of the right-angle waist of the second polarizing beam splitter faces down and the side of the inclined waist faces up. The second polarizing beam splitter film is parallel to the upper side of the second polarizing beam splitter.

6. The easily manufactured, miniaturized, two-stage isolation optical circulator according to claim 1, characterized in that: The half-wave plate and the Faraday rotator are bonded together to form a light-rotating mechanism, which is used to polarize and rotate the signal light in a single transmission direction by 90°.

7. The easily manufactured, miniaturized, two-stage isolation optical circulator according to claim 1, characterized in that: The first collimator is a dual-fiber collimator.

8. The easily manufactured, miniaturized, two-stage isolation optical circulator according to claim 7, characterized in that: The collimating parallel light angle between the two ports, Port1 and Port3, of the first collimator is 2α, and the two ports are symmetrical about the axis of the first collimator. Port1 is horizontally upward at an angle α, and Port3 is horizontally downward at an angle α.

9. The easily manufactured, miniaturized, two-stage isolation optical circulator according to claim 1, characterized in that: The second collimator is a single-fiber collimator.

10. The easily manufactured, miniaturized, two-stage isolation optical circulator according to claim 1, characterized in that: The first and second reflective sheets are bonded to the annular core base.

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