Magneto-optical isolator and laser equipment

Abstract

The utility model relates to a magneto-optical isolator and laser equipment. The magneto-optical isolator comprises a polarization light splitting element which can penetrate through first polarization light and block second polarization light, and the polarization light splitting element is provided with a first area and a second area; the optical rotation device is opposite to the first area; the magnetic optical rotation element is arranged on one side, opposite to the polarization light splitting element, of the optical rotation device and is provided with a third area and a fourth area; the conduction assembly enables light rays entering the magnetic rotation element from one of the third area and the fourth area to go back and forth in the magnetic rotation element and then to be emitted out from the other one of the third area and the fourth area; light emitted from the first area is converted into one of first polarization state light and second polarization state light after passing through the optical rotation device and the magnetic optical rotation element, and light emitted from the second area is converted into the other one of the first polarization state light and the second polarization state light after passing through the magnetic optical rotation element and the optical rotation device. According to the magneto-optical isolator, the miniaturization design can be realized.

Description

Technical Field

[0001] This application relates to the field of optical device technology, and in particular to a magneto-optical isolator and laser device. Background Technology

[0002] A magneto-optical isolator is a passive optical device that allows light to travel in only one direction while isolating the returning light. It is primarily used in optical communication and laser processing. The core component of a magneto-optical isolator is a magneto-optical crystal or other magneto-optical element. Under the influence of an external magnetic field, this element exhibits non-reciprocal optical rotation, generating a Faraday rotation angle. The magneto-optical element in a magneto-optical isolator typically needs to satisfy a specific rotation angle, resulting in a relatively large footprint for the element and the overall magnetic field structure, which is detrimental to the miniaturization design of the magneto-optical isolator. Utility Model Content

[0003] Therefore, it is necessary to provide a magneto-optical isolator and laser device to address the problem that the large space occupied by the magneto-optical element and the overall magnetic field structure is not conducive to the miniaturization design of the magneto-optical isolator.

[0004] A magneto-optical isolator, comprising:

[0005] A polarization beam splitter is capable of transmitting light in a first polarization state and blocking light in a second polarization state from passing through. The light-emitting surface of the polarization beam splitter has a first region and a second region.

[0006] An optical rotation device is disposed on the side where the light-emitting surface is located, and is opposite to the first region;

[0007] A magneto-optical element is disposed on the side of the optical rotator facing away from the polarization beam splitter. The side of the magneto-optical element facing the optical rotator has a third region opposite to the first region and a fourth region opposite to the second region.

[0008] A conduction component is provided for causing at least a portion of the light rays incident on the magneto-optical element from one of the third region and the fourth region to exit from the other of the third region and the fourth region after passing through the magneto-optical element at least once;

[0009] When the magneto-optical element is subjected to a magnetic field, the first polarized light emitted from the first region is converted into one of the first polarized light and the second polarized light after passing through the optical rotator and the magneto-optical element in sequence. The first polarized light emitted from the second region is converted into the other of the first polarized light and the second polarized light after passing through the magneto-optical element and the optical rotator in sequence.

[0010] In the aforementioned magneto-optical isolator, light rays emitted from either the first or second region via a polarization beam splitter can be converted into first polarization light by an optical rotator and a magneto-optical rotator, returning to the polarization beam splitter and then exiting through it. Similarly, light rays emitted from the other region can be converted into second polarization light by the optical rotator and a magneto-optical rotator, returning to the polarization beam splitter and being blocked by it, thus achieving unidirectional transmission. Simultaneously, a conduction component ensures that light rays passing through the magneto-optical rotator can travel at least once within the element before exiting. This increases the geometric path length of the light rays within the magneto-optical rotator without increasing its axial dimension, fully utilizing the optical rotation effect of the magneto-optical rotator. Furthermore, this allows for the reduction of the axial dimension of the magneto-optical rotator and the radial dimension of the magnetic element used to apply the magnetic field to it while maintaining a constant rotation angle, thereby reducing the overall size of the magneto-optical isolator and enabling miniaturization. Furthermore, by setting up the light-returning magneto-optical element, the light-incoming and light-outgoing sides of the magneto-optical isolator are both located on the side of the polarization beam splitter facing away from the magneto-optical element. This allows the magneto-optical isolator to interface with the light-incoming and light-outgoing port elements on the same side. At the same time, with the optical path design, only one optical rotator is needed to realize the unidirectional transmission function of the magneto-optical isolator. This also helps to reduce the size of the magneto-optical isolator and facilitates its miniaturization design.

[0011] In one embodiment, the polarization directions of the first polarized ray and the second polarized ray are perpendicular to each other. The magneto-optical element and the optical rotator are both configured to rotate the polarization direction of the passing ray by 45°. For the first polarized ray emitted from either the first region or the second region, the magneto-optical element and the optical rotator rotate the polarization direction of the ray in the same direction. For the first polarized ray emitted from the other region, the magneto-optical element and the optical rotator rotate the polarization direction of the ray in opposite directions.

[0012] In one embodiment, the first polarized light is horizontally polarized, the second polarized light is vertically polarized, and the magneto-optical rotator is configured to rotate the polarization state of light passing through the magneto-optical rotator by 45° clockwise when a magnetic field is applied. The optical rotator has a first side facing the polarizing beam splitter and a second side facing the magneto-optical rotator. The optical rotator is configured to rotate the polarization direction of light incident from the second side and passing through the optical rotator counterclockwise by 45° and to rotate the polarization direction of light incident from the first side and passing through the optical rotator clockwise by 45°.

[0013] In one embodiment, the polarization beam splitter has a polarization beam splitting surface that can transmit light of a first polarization state and reflect light of a second polarization state. In the direction from the first region to the second region, the polarization beam splitting surface is tilted relative to the light-emitting surface toward the side away from the optical rotator.

[0014] In one embodiment, the polarization beam splitter includes a polarization element and two beam splitters, both of which are right-angle prisms with their inclined surfaces facing each other. One of the beam splitters forms the light-emitting surface with its right-angled surface facing the optical rotator. The polarization element is disposed between the inclined surfaces of the two beam splitters and forms the polarization beam splitting surface.

[0015] In one embodiment, the conducting component includes a first reflecting element disposed on the side of the magneto-optical element facing away from the polarization beam splitter, the first reflecting element being used to reflect at least a portion of the light emitted from the magneto-optical element from the side of the magneto-optical element facing away from the polarization beam splitter back onto the magneto-optical element.

[0016] In one embodiment, there are multiple first reflective elements, and the number of first reflective elements is even. The conducting component further includes a second reflective element disposed on the side of the magneto-optical element facing the optical rotator. The number of second reflective elements is odd. The multiple first reflective elements are arranged sequentially at intervals in the direction from the first region to the second region. Each second reflective element is partially opposite to two adjacent first reflective elements. The second reflective element can reflect light from one of the opposing first reflective elements and the light passing through the magneto-optical element, so that the light passes through the magneto-optical element again and is projected onto the other opposing first reflective element.

[0017] In one embodiment, the conductive component is provided with two first reflective elements and one second reflective element, wherein at least a portion of one of the first reflective elements is opposite to the first region, at least a portion of the other first reflective element is opposite to the second region, and the second reflective element is partially opposite to both of the first reflective elements. Light rays entering the magneto-optical element from one of the third region and the fourth region hit one of the first reflective elements, are reflected by the first reflective element, pass through the magneto-optical element, hit the second reflective element, are reflected by the second reflective element, pass through the magneto-optical element, hit the other first reflective element, are reflected by the first reflective element, and exit from the other of the third region and the fourth region.

[0018] In one embodiment, the first reflective element includes a right-angle prism, with reflective films provided on its two right-angled faces to form reflective surfaces, and the inclined surface of the first reflective element facing the magneto-optical element; or...

[0019] The first reflective element includes two planar reflectors, the reflective surfaces of which are inclined to the surface of the magneto-optical element facing away from the optical rotator. One of the planar reflectors is used to reflect light from the magneto-optical element onto the other planar reflector, and the other planar reflector is used to reflect light back onto the magneto-optical element.

[0020] In one embodiment, the magneto-optical isolator further includes a magnetic element for applying a magnetic field to the magneto-optical element, the magnetic element being arranged circumferentially around the magneto-optical element.

[0021] A laser device includes a laser source and a magneto-optical isolator as described in any of the above embodiments, wherein the magneto-optical isolator is disposed on the light-emitting side of the laser source. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a magneto-optical isolator in some embodiments.

[0023] Figure 2 This is a schematic diagram of the forward optical path of a magneto-optical isolator in some embodiments.

[0024] Figure 3 This is a schematic diagram of the reverse optical path of a magneto-optical isolator in some embodiments.

[0025] Figure 4 This is a schematic diagram of the structure of the magneto-optical element, magnetic element, and conductive assembly in other embodiments.

[0026] Figure label:

[0027] 10. Magneto-optical isolator; 11. Polarization beam splitter; 111. First region; 112. Second region; 113. Fifth region; 114. Sixth region; 115. Polarization beam splitter surface; 12. Optical rotation device; 13. Magneto-optical rotation element; 131. Third region; 132. Fourth region; 14. Magnetic element; 15. Conducting component; 151. First reflective element; 152. Second reflective element. Detailed Implementation

[0028] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0029] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0030] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0034] Please see Figure 1 , Figure 1 This is a schematic diagram of the magneto-optical isolator 10 in some embodiments. The magneto-optical isolator 10 provided in this application includes, but is not limited to, laser devices in any applicable field such as optical fiber communication, optical sensing, optical measurement, and medical devices. The magneto-optical isolator 10 can achieve unidirectional transmission of light, which helps to prevent back-transmission of light and protect components such as the light source. When the magneto-optical isolator 10 is applied in a laser device, the laser device also includes a laser source. The magneto-optical isolator 10 can be disposed on the light-emitting side of the laser source and can allow the laser beam emitted by the laser source to pass through. At the same time, it can prevent the light that has passed through the magneto-optical isolator 10 from returning to the laser source through the magneto-optical isolator 10, thereby providing protection for the laser source. In the laser device, the magneto-optical isolator 10 can be integrated with the laser source into a laser, in which case the magneto-optical isolator 10 and the laser source are disposed in the same housing. Alternatively, the magneto-optical isolator 10 can be disposed independently outside the laser, with the laser source integrated inside the laser, and the laser and the magneto-optical isolator 10 disposed on different carriers. The magneto-optical isolator 10 and the laser source can be connected by optical fiber or other light guiding elements. The magneto-optical isolator 10 and the laser source can also be set up facing each other. The light emitted by the laser source is transmitted to the magneto-optical isolator 10 through the air. As long as the magneto-optical isolator 10 can achieve unidirectional transmission of the light emitted by the laser source, it is sufficient.

[0035] In some embodiments, the magneto-optical isolator 10 includes a polarization beam splitter 11, an optical rotator 12, a magneto-optical rotator 13, a magnetic element 14, and a conductive component 15. The polarization beam splitter 11 transmits light of a first polarization state and blocks light of a second polarization state. The light-emitting surface of the polarization beam splitter 11 has a first region 111 and a second region 112. Light entering the magneto-optical isolator 10 from the outside can enter the polarization beam splitter 11 and exit from the first region 111 or the second region 112. The optical rotator 12 includes, but is not limited to, any suitable device such as a Faraday rotator that can rotate the polarization direction of light passing through the optical rotator 12. The optical rotator 12 is located on the side where the light-emitting surface of the polarization beam splitter 11 is located and is opposite to the first region 111. At least a portion of the light emitted from the first region 111 from the polarization beam splitter 11 can reach the optical rotator 12.

[0036] The magneto-optical element 13 includes, but is not limited to, any suitable element such as a magneto-optical crystal that can exhibit non-reciprocal optical rotation when a magnetic field is applied. When a magnetic field is applied, the magneto-optical element 13 can rotate the polarization direction of light passing through it. The magneto-optical element 13 is disposed on the side of the optical rotator 12 facing away from the polarization beam splitter 11. The side of the magneto-optical element 13 facing the optical rotator 12 has a third region 131 opposite to the first region 111 and a fourth region 132 opposite to the second region 112. The magnetic element 14 is used to apply a magnetic field to the magneto-optical element 13. The magnetic element 14 includes, but is not limited to, elements such as magnets that can generate a magnetic field. The magnetic element 14 can be arranged circumferentially around the magneto-optical element 13, or it can be disposed on one or more sides of the magneto-optical element 13, as long as a magnetic field can be applied to the magneto-optical element 13 according to the optical rotation requirements.

[0037] The conduction component 15 acts as a deflector of light in the magneto-optical isolator 10. The conduction component 15 is used to cause at least a portion of the light rays incident on the magneto-optical element 13 from one of the third region 131 and the fourth region 132 to exit from the other of the third region 131 and the fourth region 132 after passing through the magneto-optical element 13 at least once.

[0038] Combination Figure 2 and Figure 3As shown, it can be understood that light rays emitted from the first region 111 of the polarization beam splitter 11 will strike the optical rotator 12, pass through the optical rotator 12, and then strike the third region 131 of the magneto-optical rotator 13. After being deflected by the conduction component 15, the light rays will travel back and forth to the magneto-optical rotator 13 at least once before exiting the magneto-optical rotator 13 from the fourth region 132 and striking the second region 112 of the polarization beam splitter 11. Similarly, light rays emitted from the second region 112 of the polarization beam splitter 11 will strike the fourth region 132 of the magneto-optical rotator 13. After being deflected by the conduction component 15, the light rays will travel back and forth to the magneto-optical rotator 13 from the third region 131 and then strike the optical rotator 12, subsequently passing through the optical rotator 12 and striking the first region 111 of the polarization beam splitter 11.

[0039] Furthermore, in some embodiments, when the magneto-optical element 13 is subjected to a magnetic field by the magnetic element 14, the first polarized light emitted from the first region 111 is converted into one of the first polarized light and the second polarized light after passing through the optical rotator 12 and the magneto-optical element 13 in sequence, and the first polarized light emitted from the second region 112 is converted into another of the first polarized light and the second polarized light after passing through the magneto-optical element 13 and the optical rotator 12 in sequence.

[0040] exist Figure 2 and Figure 3 In the illustrated embodiment, a first polarized ray emitted from the second region 112 is converted back to the first polarization state when it returns from the first region 111 to the polarization beam splitter 11, and the first polarized ray emitted from the first region 111 is converted back to the second polarization state when it returns from the second region 112 to the polarization beam splitter 11. It is understood that, with reference to... Figure 3 As shown, when external light enters the polarizing beam splitter 11 and exits from the first region 111, the first polarized light first passes through the optical rotator 12, then travels back and forth to the magneto-optical rotator 13 at least once before exiting from the magneto-optical rotator 13 and being converted into a second polarized light. This second polarized light then enters the polarizing beam splitter 11 from the second region 112, where it is blocked by the polarizing beam splitter 11 and cannot pass through. (Reference) Figure 2As shown, when external light enters the polarization beam splitter 11 and exits from the second region 112 after passing through the polarization beam splitter 11, the first polarized light first travels back and forth to the magneto-optical rotator 13 at least once before exiting the magneto-optical rotator 13 from the second region 112. After passing through the optical rotator 12, it is converted into the first polarized light and passes through the polarization beam splitter 11. Thus, when the side of the polarization beam splitter 11 facing away from the light-emitting surface has a fifth region 113 opposite to the first region 111 and a sixth region 114 opposite to the second region 112, the magneto-optical isolator 10 can achieve unidirectional transmission of light incident from the sixth region 114, while preventing light incident from the fifth region 113 from passing through the magneto-optical isolator 10.

[0041] Of course, in other embodiments, when the first polarized light emitted from the first region 111 is converted into a first polarized light after passing through the optical rotator 12 and the magneto-optical rotator 13 in sequence, and the first polarized light emitted from the second region 112 is converted into a second polarized light after passing through the magneto-optical rotator 13 and the optical rotator 12 in sequence, the magneto-optical isolator 10 can realize unidirectional transmission of the light incident on the fifth region 113, so that the light incident on the sixth region 114 cannot pass through the magneto-optical isolator 10.

[0042] The aforementioned magneto-optical isolator 10 enables unidirectional transmission and is used in optical paths to protect components such as light sources from damage caused by backlighting. Simultaneously, it can be understood that the rotation angle θ of the magneto-optical element 13 with respect to the polarization direction of the light satisfies: θ = VBL, where V is the Wilder constant, used to characterize the magneto-optical properties of the magneto-optical element 13, and is a constant when the wavelength of the incident light remains unchanged; B is the magnetic induction intensity of the magnetic field generated by the magnetic element 14; and L is the geometric path length of the light passing through the magneto-optical element 13. It is evident that when the rotation angle θ is determined, the magnetic induction intensity B is inversely proportional to the geometric path length L. Therefore, by means of the conduction component 15, the light passing through the magneto-optical element 13 can travel back and forth at least once within the magneto-optical element 13 before exiting. This increases the geometric path length of the light within the magneto-optical element 13 without increasing its axial dimension, fully utilizing the optical rotation effect of the magneto-optical element 13. Consequently, while maintaining the same rotation angle, this reduces the requirement for the magnetic induction intensity generated by the magnetic element 14, compresses the axial dimension of the magneto-optical element 13 and the radial dimension of the magnetic element 14, and compresses the volume of the magneto-optical isolator 10, thus achieving a miniaturized design of the magneto-optical isolator 10.

[0043] Furthermore, by setting up the light-returning magneto-optical element 13, the light-input side and the light-output side of the magneto-optical isolator 10 are both located on the side of the polarization beam splitter 11 facing away from the magneto-optical element 13. This allows the magneto-optical isolator 10 to interface with optical fibers and other components at the light input and output ports on the same side. At the same time, with the optical path design, only one optical rotator 12 is needed to realize the unidirectional transmission function of the magneto-optical isolator 10. This also helps to reduce the size of the magneto-optical isolator 10 and facilitates its miniaturization design.

[0044] It should be noted that the magneto-optical isolator 10 provided in this application can target the first polarized light ray to improve the transmittance of the light in the magneto-optical isolator 10 and improve the light utilization efficiency. The forward incident light ray may also include other polarized light ray ...

[0045] In some embodiments, the polarization directions of the first polarized light and the second polarized light are perpendicular to each other. For example, rotating the polarization direction of the first polarized light by 90° converts it into the second polarized light. Both the magneto-optical element 13 and the optical rotator 12 are configured to rotate the polarization direction of the passing light by 45°. In some embodiments, for the first polarized light emitted from the polarization beam splitter 11 in the second region 112, the magneto-optical element 13 and the optical rotator 12 rotate the polarization direction of the light in opposite directions. For example, when the first polarized light passes through the optical rotator 12, its polarization direction is rotated counterclockwise by 45°, and when it passes through the magneto-optical element 13, its polarization direction is rotated clockwise by 45°; or, when it passes through the optical rotator 12, its polarization direction is rotated clockwise by 45°, and when it passes through the magneto-optical element 13, its polarization direction is rotated counterclockwise by 45°. That is, the light is converted back into the first polarized light after sequentially passing through the magneto-optical element 13 and the optical rotator 12, thus enabling it to pass through the polarization beam splitter 11. For the first polarized light emitted from the polarization beam splitter 11 in the first region 111, the magneto-optical rotator 13 and the optical rotator 12 rotate the polarization direction of the light in the same direction. For example, when the first polarized light passes through the magneto-optical rotator 13 and the optical rotator 12, the polarization direction is rotated clockwise by 45°. That is to say, after the light passes through the optical rotator 12 and the magneto-optical rotator 13 in sequence, it is converted into the second polarized light and cannot pass through the polarization beam splitter 11. Thus, the magneto-optical isolator 10 realizes the unidirectional transmission function of the light incident from the sixth region 114.

[0046] Of course, in other embodiments, the magneto-optical element 13 and the optical rotator 12 may rotate at opposite angles to the polarization direction of the first polarized light emitted from the polarization beam splitter 11 in the first region 111, while rotating at the same angle to the polarization direction of the first polarized light emitted from the polarization beam splitter 11 in the second region 112. In this case, the magneto-optical isolator 10 can realize the unidirectional transmission function of the light incident from the fifth region 113.

[0047] Further, in some embodiments, the first polarized light is horizontally polarized, the second polarized light is vertically polarized, and the magneto-optical rotator 13 is configured to rotate the polarization direction of both the light incident from the third region 131 and the fourth region 132 that passes through the magneto-optical rotator 13 clockwise by 45° when a magnetic field is applied. The optical rotator 12 has a first side facing the polarizing beam splitter 11 and a second side facing the magneto-optical rotator 13. The optical rotator 12 is configured to rotate the polarization direction of the light incident from the second side that passes through the optical rotator 12 counterclockwise by 45° and to rotate the polarization direction of the light incident from the first side that passes through the optical rotator 12 clockwise by 45°.

[0048] Therefore, for reference Figure 3As shown, the first polarized light rays incident on the polarization beam splitter 11 from the fifth region 113 exit the polarization beam splitter 11 from the first region 111 and enter the optical rotator 12 from the first side. After passing through the optical rotator 12, the polarization direction is rotated 45° clockwise and then shot from the third region 131 to the magneto-optical rotator 13. After passing through the magneto-optical rotator 13 at least once, the light rays exit the magneto-optical rotator 13 from the fourth region 132. The polarization direction is rotated 45° clockwise and converted into the second polarized light rays. The light rays then shot from the second region 112 to the polarization beam splitter 11 and cannot pass through the polarization beam splitter 11 and are blocked. The first polarized light rays incident on the polarization beam splitter 11 from the sixth region 114 exit the polarization beam splitter 11 from the second region 112 and are incident on the magneto-optical element 13 from the fourth region 132. After passing through the magneto-optical element 13 at least once, they exit the magneto-optical element 13 from the third region 131, and the polarization direction is rotated 45° clockwise. Then, they are incident on the optical rotator 12 from the second side. After passing through the rotator, the polarization direction is rotated 45° counterclockwise and converted back into the first polarized light rays. Then, they are incident on the polarization beam splitter 11 from the first side and are incident on the polarization beam splitter 11. After passing through the polarization beam splitter 11, they are incident on the polarization beam splitter 11 and are emitted. Of course, in other embodiments, the magneto-optical element 13 may also be configured to rotate the polarization direction of the passing light by 45° counterclockwise, or the optical rotator 12 may rotate the polarization direction of the light incident from the second side by 45° clockwise and the polarization direction of the light incident from the second side by 45° counterclockwise. In this way, the forward transmission light of the magneto-optical isolator 10 can switch between the light incident in the fifth region 113 and the sixth region 114. For details, please refer to the above description, which will not be repeated here.

[0049] The blocking effect of the polarization beam splitter 11 on the second polarization state light includes, but is not limited to, absorption or reflection; anything that can block the second polarization state light from passing through the polarization beam splitter 11 is sufficient. (Reference) Figure 3 As shown, in this application, the polarization beam splitter 11 is used as an example to reflect light of the second polarization state. In some embodiments, the polarization beam splitter 11 has a polarization beam splitting surface 115, which can transmit light of the first polarization state and reflect light of the second polarization state. In the direction from the first region 111 to the second region 112, the polarization beam splitting surface 115 is tilted relative to the light-emitting surface towards the side away from the rotator. For example, the polarization beam splitting surface 115 can form a 45° angle with the light-emitting surface. Thus, when the magneto-optical isolator 10 conducts unidirectionally to the first polarization state light incident from the sixth region 114, the reference... Figure 3 As shown, the first polarized light rays incident from the fifth region 113 are converted into second polarized light rays after passing through the optical rotator 12 and the magneto-optical element 13 and are incident on the polarization beam splitter 115. They are reflected by the polarization beam splitter 115 and deviate from the sixth region 114 and are emitted out, unable to form a reverse light ray through the sixth region 114.

[0050] The specific structure of the polarization beam splitter 11 is not limited. In some embodiments, the polarization beam splitter 11 includes a polarization element and two beam splitters. Both beam splitters are right-angle prisms with their inclined surfaces facing each other. One of the beam splitters forms a light-emitting surface with its right-angled surface facing the optical rotator 12. The polarization element is a polarizer that can transmit light in the first polarization state and reflect light in the second polarization state. The polarization element is disposed between the inclined surfaces of the two beam splitters and forms a polarization beam splitting surface 115.

[0051] In some embodiments, the conducting component 15 includes a first reflecting element 151 disposed on the side of the magneto-optical element 13 facing away from the polarization beam splitter 11. The first reflecting element 151 is used to reflect at least a portion of the light emitted from the side of the magneto-optical element 13 facing away from the polarization beam splitter 11 back onto the magneto-optical element 13. It should be noted that, in this application, light enters the magneto-optical element 13 from the surface of the magneto-optical element 13 toward the polarization beam splitter 11, passes through the magneto-optical element 13 and reaches the side of the magneto-optical element 13 facing away from the polarization beam splitter 11, and then returns to the magneto-optical element 13. After passing through the magneto-optical element 13 and reaching the surface of the magneto-optical element 13 facing the polarization beam splitter 11, the light is considered to have made one round trip in the magneto-optical element 13. As can be seen, when the conduction component 15 is provided with only one first reflective element 151, the first reflective element 151 can reflect the light emitted from the side of the magneto-optical element 13 away from the polarization beam splitter 11 back onto the magneto-optical element 13. This allows the light to travel back and forth once within the magneto-optical element 13 before exiting from the side of the magneto-optical element 13 toward the polarization beam splitter 11. The convergence path of the light within the magneto-optical element 13 is equal to twice the axial dimension of the magneto-optical element 13, which can effectively extend the geometric path of the light within the magneto-optical element 13 and is beneficial for reducing the space occupied by the magneto-optical isolator 10.

[0052] Of course, multiple first reflective elements 151 may be provided. Each first reflective element 151 can increase one round trip of light. That is, the number of round trips of light within the magneto-optical element 13 is equal to the number of first reflective elements 151. For example, in some embodiments, multiple first reflective elements 151 are provided, and the number of first reflective elements 151 is even. The conduction assembly 15 also includes first reflective elements 151 disposed on the side of the magneto-optical element 13 facing the optical rotator 12. The number of second reflective elements 152 is odd. Multiple first reflective elements 151 are arranged sequentially at intervals in the direction from the first region 111 to the second region 112. Each second reflective element 152 is partially opposite to two adjacent first reflective elements 151. That is, the number of second reflective elements 152 is always one less than the number of first reflective elements 151. The second reflective element 152 can reflect the light from one of the opposing first reflective elements 151 and the light that has passed through the magneto-optical element 13, so that the light passes through the magneto-optical element 13 again and hits the other opposing first reflective element 151, so that each first reflective element 151 can increase the number of round trips of the light by reflecting the light.

[0053] refer to Figure 2 As shown in the example, the conductive component 15 is provided with two first reflective elements 151 and one second reflective element 152. At least a portion of one first reflective element 151 is opposite to the first region 111, and at least a portion of the other first reflective element 151 is opposite to the second region 112. The second reflective element 152 is partially opposite to both first reflective elements 151. Light rays entering the magneto-optical element 13 from the fourth region 132 pass through the magneto-optical element 13 and exit onto the first reflective element 151 opposite to the first region 111. After being reflected by the first reflective element 151, the light rays pass through the magneto-optical element 13 again and reach the second reflective element 152. After being reflected by the second reflective element 152, the light rays pass through the magneto-optical element 13 and reach the first reflective element 151 opposite to the third region 131. After being reflected by the first reflective element 151, the light rays pass through the magneto-optical element 13 and exit from the third region 131. Similarly, for light rays incident on the magneto-optical element 13 from the third region 131, the arrangement of the conduction component 15 ensures that light rays incident on the magneto-optical element 13 from either the third region 131 or the fourth region 132 can travel back and forth twice within the magneto-optical element 13 before exiting from the magneto-optical element 13 towards the polarization beam splitter 11. Of course, more first reflective elements 151 can be provided, and the number of second reflective elements 152 can be one less than the number of first reflective elements 151, as long as the conduction component 15 enables the light rays to travel back and forth multiple times within the magneto-optical element 13 before exiting from the magneto-optical element 13 towards the polarization beam splitter 11.

[0054] refer to Figure 2 and Figure 3 As shown, in some embodiments, both the first reflecting element 151 and the second reflecting element 152 are right-angle prisms. The inclined surface of the first reflecting element 151 faces the magneto-optical element 13. The two right-angled surfaces of the first reflecting element 151 are provided with reflective films to form reflective surfaces. The two right-angled surfaces of the first reflecting element 151 can both form a 45° angle with the surface of the magneto-optical element 13 facing away from the optical rotator 12, so that the light emitted from the magneto-optical element 13 can be reflected back to the magneto-optical element 13 after being reflected by the two right-angled surfaces. Light emitted from the magneto-optical element 13 onto one of the right-angled surfaces can be reflected by the right-angled surface onto the other right-angled surface, and thus reflected back to the magneto-optical element 13 by the other right-angled surface. The inclined surface of the second reflective element 152 faces the magneto-optical element 13. The two right-angled surfaces of the second reflective element 152 are provided with reflective films to form reflective surfaces. The two right-angled surfaces of the second reflective element 152 can both form a 45° angle with the surface of the magneto-optical element 13 facing the optical rotator 12. The specific reflection process is the same as that of the first reflective element 151.

[0055] refer to Figure 4 As shown, in some embodiments, both the first reflecting element 151 and the second reflecting element 152 include two plane mirrors. The reflecting surfaces of the two plane mirrors of the first reflecting element 151 are inclined to the surface of the magneto-optical element 13 facing away from the optical rotator 12, for example, at a 45° angle to the surface of the magneto-optical element 13 facing away from the optical rotator 12. One plane mirror is used to reflect light from the magneto-optical element 13 onto the other plane mirror, and the other plane mirror is used to reflect light back onto the magneto-optical element 13. The two reflecting surfaces of the second reflecting element 152 can both form a 45° angle with the surface of the magneto-optical element 13 facing the optical rotator 12, and the specific reflection process is the same as that of the first reflecting element 151.

[0056] Please see Figure 1 As shown, Figure 1 The central plane of the magneto-optical isolator 10 is indicated by a dashed line. This central plane passes through the boundary line between the fifth region 113 and the sixth region 114, the boundary line between the first region 111 and the second region 112, the boundary line between the two reflecting surfaces of the second reflecting element 152, and the boundary line between the third region 131 and the fourth region 132. The optical rotator 12 is located on one side of this central plane, and the two first reflecting elements 151 are located on opposite sides of the central plane. By rationally setting the correspondence of each element along the axial direction of the magneto-optical rotator 13, the optical path of the magneto-optical isolator 10 can be optimized, the accuracy of the optical path design can be improved, and the risk of mutual interference between the elements can be reduced.

[0057] In some embodiments, the side of the polarization splitter 11 facing away from the magneto-optical element 13 can be connected to two polarization-maintaining fibers. In this case, the magneto-optical isolator 10 can unidirectionally transmit light transmitted from one polarization-maintaining fiber to the other. For example, it can unidirectionally transmit light transmitted from the polarization-maintaining fiber opposite to the sixth region 114 into the polarization-maintaining fiber opposite to the sixth region 114. (Reference) Figure 2 As shown, the polarization-maintaining fiber can avoid the projection of the second reflective element 152 onto the surface of the polarization splitter 11 facing away from the magneto-optical element 13, so that the light emitted from the polarization-maintaining fiber opposite to the sixth region 114 can smoothly enter the magneto-optical element 13 from the fourth region 132, or so that the light emitted from the magneto-optical element 13 from the third region 131 can smoothly enter the polarization-maintaining fiber opposite to the fifth region 113, thus avoiding the light being blocked by the reflective surface of the second reflective element 152.

[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A magneto-optical isolator, characterized in that, include: A polarization beam splitter is capable of transmitting light in a first polarization state and blocking light in a second polarization state from passing through. The light-emitting surface of the polarization beam splitter has a first region and a second region. An optical rotation device is disposed on the side where the light-emitting surface is located, and is opposite to the first region; A magneto-optical element is disposed on the side of the optical rotator facing away from the polarization beam splitter. The side of the magneto-optical element facing the optical rotator has a third region opposite to the first region and a fourth region opposite to the second region. A conduction component is provided for causing at least a portion of the light rays incident on the magneto-optical element from one of the third region and the fourth region to exit from the other of the third region and the fourth region after passing through the magneto-optical element at least once; When the magneto-optical element is subjected to a magnetic field, the first polarized light emitted from the first region is converted into one of the first polarized light and the second polarized light after passing through the optical rotator and the magneto-optical element in sequence. The first polarized light emitted from the second region is converted into the other of the first polarized light and the second polarized light after passing through the magneto-optical element and the optical rotator in sequence.

2. The magneto-optical isolator according to claim 1, characterized in that, The polarization directions of the first polarized ray and the second polarized ray are perpendicular to each other. The magneto-optical element and the optical rotator are both configured to rotate the polarization direction of the passing ray by 45°. For the first polarized ray emitted from either the first region or the second region, the magneto-optical element and the optical rotator rotate the polarization direction of the ray in the same direction. For the first polarized ray emitted from the other region, the magneto-optical element and the optical rotator rotate the polarization direction of the ray in opposite directions.

3. The magneto-optical isolator according to claim 2, characterized in that, The first polarized ray is a horizontally polarized ray, and the second polarized ray is a vertically polarized ray. The magneto-optical rotator is configured to rotate the polarization direction of the ray passing through the magneto-optical rotator by 45° clockwise when a magnetic field is applied. The optical rotator has a first side facing the polarizing beam splitter and a second side facing the magneto-optical rotator. The optical rotator is configured to rotate the polarization direction of the ray incident from the second side and passing through the optical rotator by 45° counterclockwise, and to rotate the polarization direction of the ray incident from the first side and passing through the optical rotator by 45° clockwise.

4. The magneto-optical isolator according to claim 1, characterized in that, The polarization beam splitter has a polarization beam splitting surface that can transmit light of a first polarization state and reflect light of a second polarization state. In the direction from the first region to the second region, the polarization beam splitting surface is tilted relative to the light-emitting surface toward the side away from the optical rotator.

5. The magneto-optical isolator according to claim 4, characterized in that, The polarization beam splitter includes a polarization element and two beam splitters, both of which are right-angle prisms with their inclined surfaces facing each other. One of the beam splitters forms the light-emitting surface with its right-angled surface facing the optical rotator. The polarization element is disposed between the inclined surfaces of the two beam splitters and forms the polarization beam splitting surface.

6. The magneto-optical isolator according to claim 1, characterized in that, The conductive component includes a first reflective element disposed on the side of the magneto-optical element facing away from the polarization beam splitter. The first reflective element is used to reflect at least a portion of the light emitted from the magneto-optical element from the side of the magneto-optical element facing away from the polarization beam splitter back onto the magneto-optical element.

7. The magneto-optical isolator according to claim 6, characterized in that, The first reflective element is provided in multiples, and the number of the first reflective elements is even. The conductive component also includes a second reflective element disposed on the side of the magneto-optical element facing the optical rotator. The number of the second reflective elements is odd. The multiple first reflective elements are arranged sequentially at intervals in the direction from the first region to the second region. Each second reflective element is partially opposite to two adjacent first reflective elements. The second reflective element can reflect the light from one of the opposing first reflective elements and the light that has passed through the magneto-optical element, so that the light passes through the magneto-optical element again and is projected onto the other opposing first reflective element.

8. The magneto-optical isolator according to claim 7, characterized in that, The conductive component is provided with two first reflective elements and one second reflective element. At least a portion of one of the first reflective elements is opposite to the first region, and at least a portion of the other first reflective element is opposite to the second region. The second reflective element is partially opposite to both of the first reflective elements. Light rays entering the magneto-optical element from one of the third region and the fourth region hit one of the first reflective elements, are reflected by the first reflective element, pass through the magneto-optical element, hit the second reflective element, are reflected by the second reflective element, pass through the magneto-optical element, hit the other first reflective element, are reflected by the first reflective element, and exit from the other of the third region and the fourth region.

9. The magneto-optical isolator according to claim 6, characterized in that, The first reflective element includes a right-angle prism, and two right-angled faces of the first reflective element are provided with reflective films to form reflective surfaces. The inclined surface of the first reflective element faces the magneto-optical element; or, The first reflective element includes two planar reflectors, the reflective surfaces of which are inclined to the surface of the magneto-optical element facing away from the optical rotator. One of the planar reflectors is used to reflect light from the magneto-optical element onto the other planar reflector, and the other planar reflector is used to reflect light back onto the magneto-optical element.

10. A laser device, characterized in that, It includes a laser source and a magneto-optical isolator as described in any one of claims 1-9, wherein the magneto-optical isolator is disposed on the light-emitting side of the laser source.

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