Magneto-optical isolator and laser equipment

Abstract

The invention 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] The present application relates to the technical field of optical devices, and in particular to a magneto-optical isolator and a laser device. Background Art

[0002] A magneto-optical isolator is an optical passive device that allows light to travel in only one direction and isolates the returning light. It is mainly used in the fields of optical communications and laser processing. The core components of a magneto-optical isolator are magneto-optical rotatory elements such as magneto-optical crystals. Magneto-optical rotatory elements have a non-reciprocal optical rotation effect under the action of an external magnetic field and can produce a Faraday rotation angle. Magneto-optical rotatory elements in magneto-optical isolators usually have to meet a specific rotation angle, resulting in a large space occupied by the magneto-optical rotatory elements and the magnetic field structure as a whole, which is not conducive to the miniaturization design of magneto-optical isolators. Summary of the invention

[0003] Based on this, it is necessary to provide a magneto-optical isolator and laser equipment to address the problem that the magneto-optical rotation element and the magnetic field structure as a whole occupy a large space, which is not conducive to the miniaturization design of the magneto-optical isolator.

[0004] A magneto-optical isolator, comprising:

[0005] A polarization beam splitter element capable of transmitting light of a first polarization state and blocking light of a second polarization state, wherein a light emitting surface of the polarization beam splitter element has a first area and a second area;

[0006] An optical rotation device is arranged on the side where the light emitting surface is located and is opposite to the first area;

[0007] a magnetic optical rotation element, arranged on a side of the optical rotation device facing away from the polarization beam splitting element, wherein the magnetic optical rotation element has a third region opposite to the first region and a fourth region opposite to the second region on a side facing the optical rotation device;

[0008] a conducting component, configured to allow at least part of the light incident on the magneto-optical rotator element from one of the third region and the fourth region to be emitted from the other of the third region and the fourth region after traveling at least once in the magneto-optical rotator element;

[0009] When a magnetic field is applied to the magnetic rotatory element, the first polarization state light emitted from the first region is converted into one of the first polarization state light and the second polarization state light after passing through the rotatory device and the magnetic rotatory element in sequence, and the first polarization state light emitted from the second region is converted into the other of the first polarization state light and the second polarization state light after passing through the magnetic rotatory element and the rotatory device in sequence.

[0010] In the magneto-optical isolator, the first polarized light emitted from one of the first region and the second region through the polarization beam splitter can be converted into the first polarized light by the optical rotation device and the magnetic optical rotation device and return to the polarization beam splitter, and then pass through the polarization beam splitter to be emitted, and the first polarized light emitted from the other of the first region and the second region can be converted into the second polarized light by the optical rotation device and the magnetic optical rotation device and return to the polarization beam splitter, and be blocked by the polarization beam splitter and cannot be emitted, thereby realizing the unidirectional transmission function of the magneto-optical isolator. At the same time, through the conduction component, the light passing through the magnetic optical rotation device can be emitted after going back and forth at least once in the magnetic optical rotation device, thereby increasing the geometric distance of the light in the magnetic optical rotation device without increasing the axial size of the magnetic optical rotation device, making full use of the optical rotation effect of the magnetic optical rotation device on the light, and then when the rotation angle remains unchanged, it is beneficial to compress the axial size of the magnetic optical rotation device and the radial size of the magnetic element used to apply a magnetic field to the magnetic optical rotation device, which is beneficial to compress the volume of the magneto-optical isolator and realize the miniaturization design of the magneto-optical isolator. Furthermore, by setting up the magneto-optical rotation element for the light to travel back and forth, the light input side and the light output side of the magneto-optical isolator are both located on the side of the polarization splitting element facing away from the magneto-optical rotation element, so that the magneto-optical isolator can be connected to the light input and light output port elements on the same side. At the same time, in conjunction with the optical path design, only one optical rotation device needs to be set up to realize the unidirectional transmission function of the magneto-optical isolator, which is also beneficial to compressing the volume of the magneto-optical isolator and facilitating the miniaturization design of the magneto-optical isolator.

[0011] In one embodiment, the polarization directions of the first polarization state light and the second polarization state light are perpendicular to each other, the magnetic optical rotator element and the optical rotator device are both configured to rotate the polarization direction of the passing light by 45°, and for the first polarization state light emitted from one of the first region and the second region, the magnetic optical rotator element and the optical rotator device rotate the polarization direction of the light in the same direction, and for the first polarization state light emitted from the other of the first region and the second region, the magnetic optical rotator element and the optical rotator device rotate the polarization direction of the light in opposite directions.

[0012] In one embodiment, the first polarization state light is a horizontal polarization state light, the second polarization state light is a vertical polarization state light, the magnetic optical rotator element is configured to rotate the polarization state of the light passing through the magnetic optical rotator element by 45° clockwise when a magnetic field is applied, the optical rotator device has a first side facing the polarization splitting element and a second side facing the magnetic optical rotator element, and the optical rotator device is configured to rotate the polarization direction of the light incident from the second side and passing through the optical rotator device by 45° counterclockwise, and to rotate the polarization direction of the light incident from the first side and passing through the optical rotator device by 45° clockwise.

[0013] In one embodiment, the polarization splitting element has a polarization splitting surface, which can transmit the first polarization state light and reflect the second polarization state light. In the direction from the first area to the second area, the polarization splitting surface is inclined relative to the light emitting surface toward a side away from the optical rotation device.

[0014] In one embodiment, the polarization splitting element includes a polarization element and two splitting prisms, both of which are right-angle prisms, and the inclined surfaces of the two splitting prisms are opposite to each other. The right-angle surface of one of the splitting prisms facing the optical rotation device forms the light output surface, and the polarization element is arranged between the inclined surfaces of the two splitting prisms to form the polarization splitting surface.

[0015] In one of the embodiments, the conductive component includes a first reflecting element disposed on a side of the magnetic optical rotation element facing away from the polarization splitting element, and the first reflecting element is used to reflect at least part of the light emitted from the magnetic optical rotation element from the side of the magnetic optical rotation element facing away from the polarization splitting element back to the magnetic optical rotation element.

[0016] In one embodiment, there are multiple first reflective elements, and the number of the first reflective elements is an even number. The conductive component also includes a second reflective element provided on the side of the magnetic optical rotation element facing the optical rotation device, and the number of the second reflective elements is an odd number. The multiple first reflective elements are sequentially spaced in a direction from the first area to the second area, and each second reflective element is partially opposite to two adjacent first reflective elements. The second reflective element can reflect the light reflected from one of the first reflective elements and passing through the magnetic optical rotation element, so that the light passes through the magnetic optical rotation element again and is projected onto another first reflective element.

[0017] In one embodiment, the conductive component is provided with two first reflecting elements and one second reflecting element, wherein at least a portion of one of the first reflecting elements is opposite to the first region, at least a portion of the other first reflecting element is opposite to the second region, the second reflecting element is partially opposite to both of the first reflecting elements, and the light incident on the magneto-optical rotatory element from one of the third region and the fourth region is incident on one of the first reflecting elements, is reflected by the first reflecting element, passes through the magneto-optical rotatory element and incident on the second reflecting element, is reflected by the second reflecting element, passes through the magneto-optical rotatory element and incident on the other of the first reflecting elements, and is reflected by the first reflecting element and incident on the other of the third region and the fourth region through the magneto-optical rotatory element.

[0018] In one embodiment, the first reflective element comprises a right-angle prism, two right-angle surfaces of the first reflective element are provided with reflective films to form a reflective surface, and the inclined surface of the first reflective element faces the magneto-optical rotation element; or,

[0019] The first reflecting element comprises two plane reflecting mirrors, and the reflecting surfaces of the two plane reflecting mirrors are inclined to the surface of the magnetic optical rotator element facing away from the optical rotator device, one of the plane reflecting mirrors is used to reflect the light from the magnetic optical rotator element to the other plane reflecting mirror, and the other plane reflecting mirror is used to reflect the light back to the magnetic optical rotator element.

[0020] In one of the embodiments, the magneto-optical isolator further comprises a magnetic element, wherein the magnetic element is used to apply a magnetic field to the magneto-optical rotatory element, and the magnetic element is circumferentially arranged around the magneto-optical rotatory element.

[0021] A laser device comprises a laser light source and a magneto-optical isolator as described in any of the above embodiments, wherein the magneto-optical isolator is arranged on the light-emitting side of the laser light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the magneto-optical isolator in some embodiments.

[0023] Figure 2 Schematic diagram of the optical path of the forward optical path of the magneto-optical isolator in some embodiments.

[0024] Figure 3 Schematic diagram of the optical path of the reverse optical path of the magneto-optical isolator in some embodiments.

[0025] Figure 4 Schematic diagram of the structure of magneto-optical elements, magnetic elements and conductive components in other embodiments.

[0026] Reference numerals:

[0027] 10. Magneto-optical isolator; 11. Polarization splitter element; 111. First region; 112. Second region; 113. Fifth region; 114. Sixth region; 115. Polarization 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 reflecting element; 152. Second reflecting element. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0029] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0030] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0032] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If present, 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 implementation method.

[0034] See also Figure 1 , Figure 1 It is a structural schematic diagram of the magneto-optical isolator 10 in some embodiments. The magneto-optical isolator 10 provided in the present application includes but is not limited to being used in laser equipment in any applicable field such as optical fiber communication, optical sensing, optical measurement, medical equipment, etc. The magneto-optical isolator 10 can realize unidirectional transmission of light, which is beneficial to prevent the light from being transmitted in reverse and protect components such as light sources. When the magneto-optical isolator 10 is applied to a laser device, the laser device also includes a laser light source. The magneto-optical isolator 10 can be arranged on the light-emitting side of the laser light source, and can allow the laser beam emitted by the laser light source to pass through, and can prevent the light passing through the magneto-optical isolator 10 from passing through the magneto-optical isolator 10 again and returning to the laser light source, thereby providing protection for the laser light source. In the laser device, the magneto-optical isolator 10 can be integrated with the laser light source into a laser, and the magneto-optical isolator 10 and the laser light source are arranged in the same housing, and the magneto-optical isolator 10 can also be independently arranged outside the laser, and the laser light source is integrated in the laser, and the laser and the magneto-optical isolator 10 are respectively arranged on different carriers. Optical fiber transmission can be achieved between the magneto-optical isolator 10 and the laser light source through optical fiber and other light-guiding elements. The magneto-optical isolator 10 and the laser light source can also be arranged opposite each other, and the light emitted by the laser light 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 light source, it will be 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 can transmit light of a first polarization state and block light of a second polarization state from transmitting. The light exiting 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 pass through the polarization beam splitter 11 and exit the polarization beam splitter 11 from the first region 111 or the second region 112. The optical rotator 12 includes but is not limited to any suitable device that can rotate the polarization direction of light passing through the optical rotator 12, such as a Faraday rotator. The optical rotator 12 is disposed on the side of the light exiting surface of the polarization beam splitter 11 and is opposite to the first region 111. At least part of the light exiting the polarization beam splitter 11 from the first region 111 can be emitted onto the optical rotator 12.

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

[0037] The conductive component 15 plays the role of deflecting light in the magneto-optical isolator 10. The conductive component 15 is used to make at least part of the light incident on the magneto-optical element 13 from one of the third region 131 and the fourth region 132 be emitted from the other of the third region 131 and the fourth region 132 after at least one round trip in the magneto-optical element 13.

[0038] Combination Figure 2 and Figure 3As shown, it can be understood that the light emitted from the polarization beam splitter 11 from the first area 111 will hit the optical rotator 12, and then hit the third area 131 of the magnetic optical rotator 13 through the optical rotator 12, and then, after going back and forth with the magnetic optical rotator 13 at least once under the deflection of the transmission component 15, it will be emitted from the magnetic optical rotator 13 from the fourth area 132 and hit the second area 112 of the polarization beam splitter 11. The light emitted from the polarization beam splitter 11 from the second area 112 will hit the fourth area 132 of the magnetic optical rotator 13, and then, after going back and forth with the magnetic optical rotator 13 at least once under the deflection of the transmission component 15, it will be emitted from the third area 131 and hit the optical rotator 12, and then, after going back and forth with the magnetic optical rotator 13 at least once under the deflection of the transmission component 15, it will be emitted from the magnetic optical rotator 13 and hit the optical rotator 12, and then, after passing through the optical rotator 12, it will hit the first area 111 of the polarization beam splitter 11.

[0039] Furthermore, in some embodiments, when the magnetic element 14 applies a magnetic field to the magnetic rotatory element 13, the first polarization state light emitted from the first region 111 is converted into one of the first polarization state light and the second polarization state light after passing through the optical rotatory device 12 and the magnetic rotatory element 13 in sequence, and the first polarization state light emitted from the second region 112 is converted into the other of the first polarization state light and the second polarization state light after passing through the magnetic rotatory element 13 and the optical rotatory device 12 in sequence.

[0040] exist Figure 2 and Figure 3 In the embodiment shown, the first polarization state light emitted from the second area 112 is converted into the first polarization state light again when it is emitted from the first area 111 back to the polarization splitter 11, and the first polarization state light emitted from the first area 111 is converted into the second polarization state light when it is emitted from the second area 112 back to the polarization splitter 11. It can be understood that, with reference to Figure 3 As shown, when external light enters the polarization beam splitter 11 and is emitted from the first region 111 through the polarization beam splitter 11, the first polarization state light first passes through the optical rotation device 12, and then goes back and forth between the magnetic optical rotation device 13 at least once before being emitted from the magnetic optical rotation device 13 and converted into the second polarization state light, and then enters the polarization beam splitter 11 from the second region 112, and is blocked by the polarization beam splitter 11 and cannot pass through. Figure 2As shown, when external light enters the polarization beam splitter 11 and is emitted from the second region 112 through the polarization beam splitter 11, the light of the first polarization state first goes back and forth between the magnetic optical rotation element 13 at least once and then is emitted from the second region 112 through the magnetic optical rotation element 13, and is converted into the light of the first polarization state through the optical rotation element 12 and passes through the polarization beam splitter 11. Therefore, when the side of the polarization beam splitter 11 facing away from the light exiting surface has the fifth region 113 opposite to the first region 111 and the sixth region 114 opposite to the second region 112, the magneto-optical isolator 10 can realize unidirectional transmission of the light incident from the sixth region 114, and the light incident from the fifth region 113 cannot pass through the magneto-optical isolator 10.

[0041] Of course, in other embodiments, when the first polarization state light emitted from the first region 111 is converted into the first polarization state light after passing through the optical rotation device 12 and the magneto-optical rotation device 13 in sequence, and the first polarization state light emitted from the second region 112 is converted into the second polarization state light after passing through the magneto-optical rotation device 13 and the optical rotation device 12 in sequence, the magneto-optical isolator 10 can realize unidirectional transmission of the light incident to the fifth region 113, while making it impossible for the light incident to the sixth region 114 to pass through the magneto-optical isolator 10.

[0042] The magneto-optical isolator 10 can realize the unidirectional transmission function and is used in the optical path to protect the light source and other components from being damaged by the reverse light. At the same time, it can be understood that the rotation angle θ of the magneto-optical rotation element 13 to the polarization direction of the light satisfies: θ=VBL, where V is the Verdet constant, which is used to characterize the magneto-optical properties of the magneto-optical rotation element 13 and is a constant when the wavelength of the incident light is constant, B is the magnetic induction intensity of the magnetic field generated by the magnetic element 14, and L is the geometric path of the light passing through the magneto-optical rotation element 13 in the magneto-optical rotation element 13. It can be seen that when the rotation angle θ is determined, the magnetic induction intensity B is inversely proportional to the geometric path L. Therefore, the conducting component 15 allows the light passing through the magneto-optical rotator element 13 to be emitted after having traveled back and forth at least once in the magneto-optical rotator element 13, thereby increasing the geometric distance of the light in the magneto-optical rotator element 13 without increasing the axial size of the magneto-optical rotator element 13, making full use of the optical rotation effect of the magneto-optical rotator element 13 on the light, and further helping to reduce the requirement on the magnetic induction intensity generated by the magnetic element 14 when the rotation angle remains unchanged, helping to compress the axial size of the magneto-optical rotator element 13 and the radial size of the magnetic element 14, helping to compress the volume of the magneto-optical isolator 10, and realizing the miniaturized design of the magneto-optical isolator 10.

[0043] Furthermore, by setting up the magneto-optical rotation element 13 for the light to travel back and forth, the light input side and the light output side of the magneto-optical isolator 10 are both located on the side of the polarization splitting element 11 facing away from the magneto-optical rotation element 13, so that the magneto-optical isolator 10 can be connected to the optical fiber and other components of the light input and light output ports on the same side. At the same time, in conjunction with the optical path design, only one optical rotation device 12 needs to be set up to realize the unidirectional transmission function of the magneto-optical isolator 10, which is also beneficial to compressing the volume of the magneto-optical isolator 10 and facilitating the miniaturization design of the magneto-optical isolator 10.

[0044] It should be noted that the forward incident light targeted by the magneto-optical isolator 10 provided in the present application can be a first polarization state light, so as to improve the transmittance of the light in the magneto-optical isolator 10 and improve the light utilization efficiency. The forward incident light can also include other polarization state lights, or be free polarization state lights. Then, when the light is incident on the magneto-optical isolator 10, the first polarization state light component in the light can pass through the polarization splitter element 11.

[0045] In some embodiments, the polarization directions of the first polarized light and the second polarized light are perpendicular to each other. For example, the polarization direction of the first polarized light can be converted into the second polarized light by rotating the polarization direction of the first polarized light by 90°. The magnetic optical rotator element 13 and the optical rotator device 12 are both configured to rotate the polarization direction of the light passing through by 45°. In some embodiments, for the first polarized light emitted from the second region 112 of the polarization beam splitter element 11, the magnetic optical rotator element 13 and the optical rotator device 12 rotate the polarization direction of the light in opposite directions. For example, when the first polarized light passes through the optical rotator device 12, the polarization direction is rotated by 45° counterclockwise, and when passing through the magnetic optical rotator element 13, the polarization direction is rotated by 45° clockwise, or when passing through the optical rotator device 12, the polarization direction is rotated by 45° clockwise, and when passing through the magnetic optical rotator element 13, the polarization direction is rotated by 45° counterclockwise. That is, after the light passes through the magnetic optical rotator element 13 and the optical rotator device 12 in sequence, it is converted into the first polarized light again and can pass through the polarization beam splitter element 11. For the first polarization state light emitted from the polarization splitter element 11 from the first region 111, the magnetic rotator element 13 and the optical rotator device 12 rotate the polarization direction of the light in the same direction. For example, when the first polarization state light passes through the magnetic rotator element 13 and the optical rotator device 12, the polarization direction is rotated 45° clockwise. That is to say, after the light passes through the optical rotator device 12 and the magnetic rotator element 13 in sequence, it is converted into the second polarization state light and cannot pass through the polarization splitter element 11, thereby realizing the unidirectional transmission function of the magneto-optical isolator 10 for the light incident from the sixth region 114.

[0046] Of course, in other embodiments, the magneto-optical rotator element 13 and the rotator device 12 may also have opposite rotation angles for the polarization direction of the first polarization state light emitted from the polarization splitter element 11 from the first region 111, while have the same rotation angles for the polarization direction of the first polarization state light emitted from the polarization splitter element 11 from the second region 112. In this case, the magneto-optical isolator 10 can realize the unidirectional transmission function for the light incident from the fifth region 113.

[0047] Further, in some embodiments, the first polarized light is a horizontal polarized light, and the second polarized light is a vertical polarized light. The magnetic optical rotator 13 is configured to rotate the polarization directions of the light incident from the third region 131 and the fourth region 132 and passing through the magnetic optical rotator 13 by 45° clockwise when a magnetic field is applied. The optical rotator 12 has a first side facing the polarization beam splitting element 11 and a second side facing the magnetic optical rotator 13. The optical rotator 12 is configured to rotate the polarization direction of the light incident from the second side and passing through the optical rotator 12 by 45° counterclockwise, and to rotate the polarization direction of the light incident from the first side and passing through the optical rotator 12 by 45° clockwise.

[0048] Therefore, reference Figure 3As shown, the first polarized light entering the polarization beam splitter 11 from the fifth region 113 is emitted from the polarization beam splitter 11 from the first region 111 and enters the optical rotation device 12 from the first side. After passing through the optical rotation device 12, the polarization direction is rotated 45° clockwise. The light enters the magnetic optical rotation device 13 from the third region 131. After at least one round trip in the magnetic optical rotation device 13, the light exits the magnetic optical rotation device 13 from the fourth region 132. The polarization direction is rotated 45° clockwise and converted into the second polarized light. The light enters the polarization beam splitter 11 from the second region 112 and cannot pass through the polarization beam splitter 11 and is blocked. The first polarization state light beam incident on the polarization beam splitter 11 from the sixth region 114 is emitted from the polarization beam splitter 11 from the second region 112, and is emitted from the polarization beam splitter 11 from the fourth region 132, and is emitted from the magnetic optical rotation element 13 from the third region 131 after at least one round trip in the magnetic optical rotation element 13, and the polarization direction is rotated 45° clockwise, and then enters the optical rotation element 12 from the second side, and the polarization direction is rotated 45° counterclockwise after passing through the rotation element and is converted into the first polarization state light beam again, and then is emitted from the first side and is emitted to the polarization beam splitter 11, and is emitted through the polarization beam splitter 11. Of course, in other embodiments, the magneto-optical rotator element 13 may also be configured to be able to rotate the polarization direction of the passing light 45° counterclockwise, or the optical rotator device 12 may be able to rotate the polarization direction of the light incident from the second side 45° clockwise and rotate the polarization direction of the light incident from the second side 45° counterclockwise, then the forward transmission light of the magneto-optical isolator 10 may be switched between the light incident from the fifth region 113 and the light incident from the sixth region 114, for details which may be obtained by referring to the above records and 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, as long as the second polarization state light can be blocked from passing through the polarization beam splitter 11. Figure 3 As shown, in the present application, the polarization splitter element 11 is taken as an example that it can reflect the second polarization state light. In some embodiments, the polarization splitter element 11 has a polarization splitter surface 115, and the polarization splitter surface 115 can transmit the first polarization state light and reflect the second polarization state light. In the direction from the first area 111 to the second area 112, the polarization splitter surface 115 is inclined relative to the light emitting surface toward the side away from the rotator. For example, the polarization splitter surface 115 can form an angle of 45° with the light emitting surface. Therefore, when the magneto-optical isolator 10 unidirectionally transmits the first polarization state light incident from the sixth area 114, the reference Figure 3 As shown, the first polarization state light incident from the fifth region 113 is converted into the second polarization state light after passing through the optical rotation device 12 and the magnetic optical rotation element 13 and is incident on the polarization splitting plane 115, is reflected by the polarization splitting plane 115 and deviates from the sixth region 114 and is unable to pass through the sixth region 114 to form reverse light.

[0050] The specific structural setting of the polarization splitter element 11 is not limited. In some embodiments, the polarization splitter element 11 includes a polarization element and two splitter prisms. The two splitter prisms are right-angle prisms. The inclined surfaces of the two splitter prisms are opposite to each other. The right-angle surface of one of the splitter prisms faces the optical rotation device 12 to form a light output surface. The polarization element is a polarizer that can transmit the first polarization state light and reflect the second polarization state light. The polarization element is arranged between the inclined surfaces of the two splitter prisms to form a polarization splitter surface 115.

[0051] In some embodiments, the conducting component 15 includes a first reflecting element 151 disposed on the side of the magnetic optical rotator element 13 facing away from the polarization beam splitter element 11, and the first reflecting element 151 is used to reflect at least part of the light of the magnetic optical rotator element 13 emitted from the side of the magnetic optical rotator element 13 facing away from the polarization beam splitter element 11 back to the magnetic optical rotator element 13. It should be noted that in the present application, when the light enters the magnetic optical rotator element 13 from the surface of the magnetic optical rotator element 13 facing the polarization beam splitter element 11, passes through the magnetic optical rotator element 13 and hits the surface of the magnetic optical rotator element 13 facing away from the polarization beam splitter element 11, then returns to the magnetic optical rotator element 13 again, passes through the magnetic optical rotator element 13 and hits the surface of the magnetic optical rotator element 13 facing the polarization beam splitter element 11, it is considered that the light passes through the magnetic optical rotator element 13 once. It can be seen that when the conducting component 15 is provided with only one first reflecting element 151, the first reflecting element 151 can reflect the light emitted from the magneto-optical rotator element 13 from the side of the magneto-optical rotator element 13 facing away from the polarization splitting element 11 back to the magneto-optical rotator element 13, so that the light is emitted from the magneto-optical rotator element 13 toward the side of the polarization splitting element 11 after a round trip in the magneto-optical rotator element 13, and the collective path of the light in the magneto-optical rotator element 13 is equal to twice the axial size of the magneto-optical rotator element 13, which can effectively extend the geometric path of the light in the magneto-optical rotator element 13, which is beneficial to compressing the occupied space of the magneto-optical isolator 10.

[0052] Of course, there may be multiple first reflective elements 151, and each first reflective element 151 can increase one round trip of the light, that is, the number of round trips of the light in the magneto-optical rotation element 13 is equal to the number of first reflective elements 151. For example, in some embodiments, there are multiple first reflective elements 151, the number of first reflective elements 151 is an even number, the conductive component 15 further includes a first reflective element 151 disposed on the side of the magneto-optical rotation element 13 facing the optical rotation device 12, the number of second reflective elements 152 is an odd number, and the multiple first reflective elements 151 are sequentially spaced 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 reflected by one of the opposite first reflective elements 151 and passing through the magneto-optical rotation element 13, so that the light passes through the magneto-optical rotation element 13 again and is projected onto the other opposite 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 present application, the conductive component 15 is provided with two first reflective elements 151 and one second reflective element 152 as an example, wherein at least a portion of one of the first reflective elements 151 is opposite to the first region 111, at least a portion of the other first reflective element 151 is opposite to the second region 112, and the second reflective element 152 is partially opposite to both first reflective elements 151. The light incident into the magneto-optical element 13 from the fourth region 132 passes through the magneto-optical element 13 and then is emitted to the first reflective element 151 opposite to the first region 111, is reflected by the first reflective element 151 and then passes through the magneto-optical element 13 again and then is emitted to the second reflective element 152, is reflected by the second reflective element 152 and then passes through the magneto-optical element 13 and then is emitted to the first reflective element 151 opposite to the third region 131, is reflected by the first reflective element 151 and then passes through the magneto-optical element 13 and then is emitted from the third region 131. The same is true for the light incident on the magneto-optical rotator element 13 from the third region 131. It can be seen that the arrangement of the transmission component 15 enables the light incident on the magneto-optical rotator element 13 from one of the third region 131 and the fourth region 132 to travel back and forth twice in the magneto-optical rotator element 13 and then be emitted from the magneto-optical rotator element 13 toward the side of the polarization splitter element 11. Of course, the number of first reflection elements 151 can be greater, and the number of second reflection elements 152 can be correspondingly set to be one less than the number of first reflection elements 151, as long as the transmission component 15 can enable the light to travel back and forth multiple times in the magneto-optical rotator element 13 and then be emitted from the magneto-optical rotator element 13 toward the side of the polarization splitter element 11.

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

[0055] refer to Figure 4 As shown, in other embodiments, the first reflective element 151 and the second reflective element 152 each include two plane reflectors, and the reflective surfaces of the two plane reflectors of the first reflective element 151 are both inclined to the surface of the magneto-optical rotatory element 13 facing away from the optical rotatory device 12, for example, both form an angle of 45° with the surface of the magneto-optical rotatory element 13 facing away from the optical rotatory device 12. One of the plane reflectors is used to reflect the light from the magneto-optical rotatory element 13 to the other plane reflector, and the other plane reflector is used to reflect the light back to the magneto-optical rotatory element 13. The two reflective surfaces of the second reflective element 152 can both form an angle of 45° with the surface of the magneto-optical rotatory element 13 facing the optical rotatory device 12, and the specific reflection process is the same as that of the first reflective element 151.

[0056] See also Figure 1 As shown, Figure 1 The dotted line indicates the center plane of the magneto-optical isolator 10, which 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 reflection surfaces of the second reflection element 152, and the boundary line between the third region 131 and the fourth region 132. The optical rotation device 12 is arranged on one side of the center plane, and the two first reflection elements 151 are respectively located on opposite sides of the center plane. By reasonably setting the corresponding relationship of each element in the axial direction of the magneto-optical rotation element 13, the optical path direction 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 each element can be reduced.

[0057] In some embodiments, the side of the polarization splitting element 11 facing away from the magnetic rotation element 13 can be connected to two polarization-maintaining optical fibers, so that the magneto-optical isolator 10 can realize unidirectional transmission of light transmitted by one polarization-maintaining optical fiber to another polarization-maintaining optical fiber, for example, it can unidirectionally transmit light transmitted by the polarization-maintaining optical fiber opposite to the sixth region 114 to the polarization-maintaining optical fiber opposite to the sixth region 114. Figure 2 As shown, the polarization-maintaining optical fiber can avoid the projection of the second reflective element 152 on the surface of the polarization splitting element 11 facing away from the magnetic rotatory element 13, so that the light emitted from the polarization-maintaining optical fiber opposite to the sixth area 114 can smoothly enter the magnetic rotatory element 13 from the fourth area 132, or the light emitted from the magnetic rotatory element 13 from the third area 131 can smoothly enter the polarization-maintaining optical fiber opposite to the fifth area 113, thereby avoiding the light being blocked by the reflective surface of the second reflective element 152.

[0058] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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 above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A magneto-optical isolator, characterized in that: include: A polarization beam splitter element capable of transmitting light of a first polarization state and blocking light of a second polarization state, wherein a light emitting surface of the polarization beam splitter element has a first area and a second area; An optical rotation device is arranged on the side where the light emitting surface is located and is opposite to the first area; a magnetic optical rotation element, arranged on a side of the optical rotation device facing away from the polarization beam splitting element, wherein the magnetic optical rotation element has a third region opposite to the first region and a fourth region opposite to the second region on a side facing the optical rotation device; a conductive component, configured to allow at least part of the light incident on the magneto-optical rotator element from one of the third region and the fourth region to be emitted from the other of the third region and the fourth region after traveling at least once in the magneto-optical rotator element; When a magnetic field is applied to the magnetic rotatory element, the first polarization state light emitted from the first region is converted into one of the first polarization state light and the second polarization state light after passing through the rotatory device and the magnetic rotatory element in sequence, and the first polarization state light emitted from the second region is converted into the other of the first polarization state light and the second polarization state light after passing through the magnetic rotatory element and the rotatory device in sequence.

2. The magneto-optical isolator according to claim 1, characterized in that: The polarization directions of the first polarization state light and the second polarization state light are perpendicular to each other, the magnetic optical rotator element and the optical rotator device are both configured to rotate the polarization direction of the passing light by 45°, and for the first polarization state light emitted from one of the first area and the second area, the magnetic optical rotator element and the optical rotator device rotate the polarization direction of the light in the same direction, and for the first polarization state light emitted from the other of the first area and the second area, the magnetic optical rotator element and the optical rotator device rotate the polarization direction of the light in opposite directions.

3. The magneto-optical isolator according to claim 2, characterized in that: The first polarization state light is a horizontal polarization state light, the second polarization state light is a vertical polarization state light, the magnetic optical rotator element is configured to rotate the polarization direction of the light passing through the magnetic optical rotator element by 45° clockwise when a magnetic field is applied, the optical rotator device has a first side facing the polarization splitting element and a second side facing the magnetic optical rotator element, and the optical rotator device is configured to rotate the polarization direction of the light incident from the second side and passing through the optical rotator device by 45° counterclockwise, and to rotate the polarization direction of the light incident from the first side and passing through the optical rotator device by 45° clockwise.

4. The magneto-optical isolator according to claim 1, characterized in that: The polarization splitting element has a polarization splitting surface, which can transmit the first polarization state light and reflect the second polarization state light. In the direction from the first area to the second area, the polarization splitting surface is inclined relative to the light emitting surface toward a side away from the optical rotation device.

5. The magneto-optical isolator according to claim 4, characterized in that: The polarization beam splitting element comprises a polarization element and two beam splitting prisms, both of which are right-angle prisms, and the inclined surfaces of the two beam splitting prisms are opposite to each other, wherein the right-angle surface of one of the beam splitting prisms facing the optical rotation device forms the light output surface, and the polarization element is arranged between the inclined surfaces of the two beam splitting prisms to form the polarization beam splitting surface.

6. The magneto-optical isolator according to claim 1, characterized in that: The transmission component includes a first reflecting element arranged on a side of the magnetic optical rotation element facing away from the polarization splitting element, and the first reflecting element is used to reflect at least part of the light emitted from the magnetic optical rotation element from the side of the magnetic optical rotation element facing away from the polarization splitting element back to the magnetic optical rotation element.

7. The magneto-optical isolator according to claim 6, characterized in that: There are multiple first reflecting elements, and the number of the first reflecting elements is an even number. The conductive component also includes a second reflecting element arranged on the side of the magnetic optical rotation element facing the optical rotation device, and the number of the second reflecting elements is an odd number. The multiple first reflecting elements are sequentially spaced in the direction from the first area to the second area, and each second reflecting element is partially opposite to two adjacent first reflecting elements. The second reflecting element can reflect the light reflected by one of the first reflecting elements and passing through the magnetic optical rotation element, so that the light passes through the magnetic optical rotation element again and is projected onto the other first reflecting element.

8. The magneto-optical isolator according to claim 7, characterized in that: The conductive component is provided with two first reflecting elements and one second reflecting element, wherein at least a portion of one of the first reflecting elements is opposite to the first region, and at least a portion of the other first reflecting element is opposite to the second region, and the second reflecting element is partially opposite to both of the first reflecting elements. Light incident on the magneto-optical rotatory element from one of the third region and the fourth region is incident on one of the first reflecting elements, is reflected by the first reflecting element, passes through the magneto-optical rotatory element and is incident on the second reflecting element, is reflected by the second reflecting element, passes through the magneto-optical rotatory element and is incident on the other of the first reflecting elements, and is reflected by the first reflecting element and passes through the magneto-optical rotatory element and is emitted 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 reflecting element comprises a right-angle prism, two right-angle surfaces of the first reflecting element are provided with reflecting films to form reflecting surfaces, and the inclined surface of the first reflecting element faces the magneto-optical rotation element; or, The first reflecting element comprises two plane reflecting mirrors, and the reflecting surfaces of the two plane reflecting mirrors are inclined to the surface of the magnetic optical rotator element facing away from the optical rotator device, one of the plane reflecting mirrors is used to reflect the light from the magnetic optical rotator element to the other plane reflecting mirror, and the other plane reflecting mirror is used to reflect the light back to the magnetic optical rotator element.

10. A laser device, characterized in that: It comprises a laser light source and a magneto-optical isolator as described in any one of claims 1 to 9, wherein the magneto-optical isolator is arranged on the light output side of the laser light source.

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