A magneto-optical switch with lossless switching

Abstract

The present application discloses a lossless switching magneto-optical switch, belonging to the field of optics. A first polarization beam splitter decomposes parallel light input from an input end into two sub-beams, p-light and s-light, with orthogonal polarization directions. The p-light and s-light form two main optical paths. A first half-wave plate can rotate the polarization direction of the p-light by 135° clockwise along the optical path transmission direction and the polarization direction of the s-light by 45° counterclockwise along the optical path transmission direction. A Faraday rotator crystal applies magnetic fields in different directions to rotate the main optical path by 45° clockwise or 45° counterclockwise, simultaneously generating two weak optical paths. A second polarization beam splitter converges the p-light and s-light of the two main optical paths to a first output end or a second output end, and converges the p-light and s-light of the two weak optical paths to another second output end or the first output end. When the optical channel is switched, both the strong light and the weak light are coupled into different channels. The sum of the energies at the first and second output ends and the sum of the energies at the first and second output ends after the switch are completed are always in a stable state, bringing stability to network transmission.

Description

Technical Field

[0001] The present invention relates to the field of optical elements, and in particular to a magneto-optical switch for lossless switching. Background Art

[0002] In the field of fiber-optic communications, optical switches, as a key passive component, are widely used to selectively switch optical signals within fiber-optic communication networks. Magneto-optical switches utilize the Faraday magneto-optical effect, primarily by altering the direction of an applied magnetic field to change the Faraday rotation angle within a magneto-optical crystal, thereby switching the optical path. Compared to traditional optical switches, magneto-optical switches offer advantages such as fast switching speed, no moving parts, and high stability, and are garnering increasing attention and research.

[0003] When the magneto-optical switch is working, the light on the connected path is the main energy, and the light on the closed path is not actually in a light-free state, but the light energy is relatively weak. During the actual switching process of the existing magneto-optical switch, when the light energy switches from one path to another, the sum of the light energy in each port cannot maintain a stable value. The energy loss caused by the switch switching affects the stability of the optical transmission system. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide a magneto-optical switch with lossless switching in which the sum of the optical energy in each port maintains a stable value.

[0005] One of the purposes of the present invention is achieved by the following technical solution:

[0006] A lossless switching magneto-optical switch comprises an input end, a first output end, a second output end, and a first polarization beam splitter prism, a first half-wave plate, a Faraday rotator crystal, and a second polarization beam splitter prism arranged in sequence. The input end is located on the side of the first polarization beam splitter prism away from the first half-wave plate, the first output end and the second output end are located on the side of the second polarization beam splitter prism away from the Faraday rotator crystal, the first polarization beam splitter prism and the second polarization beam splitter prism each comprise two crystals, the junction of the two crystals being coated, and the first polarization beam splitter prism decomposes the parallel light input from the input end into two sub-beams with orthogonal polarization directions. Light beams p and s, the p and s forming two main optical paths; the first half-wave plate capable of rotating the polarization direction of the p light by 135° clockwise along the optical path transmission direction, and the polarization direction of the s light by 45° counterclockwise along the optical path transmission direction; the Faraday rotator crystal applying magnetic fields in different directions rotates the main optical path by 45° clockwise or 45° counterclockwise, while simultaneously maintaining the polarization direction of a very weak light beam without rotating to produce two weak optical paths; the second polarization beam splitter converges the p and s lights of the two main optical paths to the first output end or the second output end, and converges the p and s lights of the two weak optical paths to the other second output end or the first output end.

[0007] Furthermore, the two crystals of the first polarization beam splitter are respectively a parallelogram crystal and a triangular crystal, and the mating surfaces of the parallelogram crystal and the triangular crystal are coated with a film, and the film reflects S light.

[0008] Furthermore, the two crystals of the second polarization beam splitter are respectively two parallelogram crystals, and the bonding surfaces of the two parallelogram crystals are coated with a film, and the film reflects s ​​light and transmits p light.

[0009] Furthermore, the lossless switching magneto-optical switch also includes a second half-wave plate and a third half-wave plate, the second half-wave plate is located between the first polarization beam splitter prism and the first half-wave plate, the second half-wave plate is located on the p-light channel emitted from the first polarization beam splitter prism, the third half-wave plate is located between the Faraday rotator crystal and the second polarization beam splitter prism, and the third half-wave plate is located on the s-light channel emitted from the first polarization beam splitter prism.

[0010] Furthermore, the position of the second half-wave plate corresponds to the triangular crystal of the first polarization beam splitter prism, and the position of the third half-wave plate corresponds to the parallelogram crystal of the first polarization beam splitter prism.

[0011] Furthermore, the lossless switching magneto-optical switch further includes a first single-fiber collimator, which is located at the input end and collimates the divergent light beam output by the optical fiber into a parallel light beam.

[0012] Furthermore, the lossless switching magneto-optical switch further includes a second single-fiber collimator and a third single-fiber collimator, and the second single-fiber collimator and the third single-fiber collimator are respectively located at the first output end and the second output end.

[0013] Furthermore, the parallel light beam emitted by the first single-fiber collimator, the light beam received by the second single-fiber collimator, and the light beam received by the third single-fiber collimator are parallel to each other.

[0014] Compared with the prior art, the present invention provides a lossless switching magneto-optical switch comprising a first polarization splitter prism, a first half-wave plate, a Faraday rotator crystal, and a second polarization splitter prism, the input end of which is located on the side of the first polarization splitter prism away from the first half-wave plate, the first output end and the second output end are located on the side of the second polarization splitter prism away from the Faraday rotator crystal, the first polarization splitter prism and the second polarization splitter prism each comprising two crystals, the junction of the two crystals being coated, the first polarization splitter prism converting the flat light inputted at the input end into a polarization splitter prism. The traveling light is decomposed into two sub-beams, p-light and s-light, with orthogonal polarization directions. The p-light and s-light are the two main light paths. The first half-wave plate can rotate the polarization direction of the p-light by 135° clockwise along the direction of light transmission, and the polarization direction of the s-light by 45° counterclockwise along the direction of light transmission. The Faraday rotator crystal rotates the main light path by 45° clockwise or 45° counterclockwise by applying magnetic fields in different directions. At the same time, the polarization direction of the very weak light beam does not rotate to produce two weak light paths. The second polarization splitter prism rotates the p-light of the two main light paths. The strong and weak light paths converge to the first output end or the second output end, and the p and s light of the two weak light paths converge to the other second output end or the first output end. The polarization direction of the light beam is changed by setting a polarization beam splitter prism, a first half-wave plate, and a Faraday rotator crystal to ensure that all light beams can be accurately converged to the output end after passing through the second polarization beam splitter prism. When the optical channel is switched, the intensity of the strong light and the weak light paths is essentially exchanged, and the strong light and the weak light are coupled into different channels. When the switch is switched, a certain response time is actually required for the switching to be completed. During the time when the switching starts but the switching is not completed, the energy of the weak light increases during the energy conversion between the strong light and the weak light. However, since the magneto-optical switch in the prior art does not couple the weak light channel, instability occurs in the system and it will not stabilize until all switches are completed. In the present application, the sum of the energy at the first output end and the second output end and the sum of the energy at the first output end and the second output end after the switching is completed are always in a stable state, which brings stability to the network transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A perspective view of a magneto-optical switch with lossless switching according to a first embodiment of the present invention;

[0016] Figure 2 This is a light path diagram from the input end to the first output end during operation in the first embodiment of the present invention;

[0017] Figure 3 This is a light path diagram from the input end to the second output end during operation in the first embodiment of the present invention;

[0018] Figure 4 A perspective view of a magneto-optical switch with lossless switching according to a second embodiment of the present invention;

[0019] Figure 5 This is a light path diagram from the input end to the first output end during operation in the second embodiment of the present invention;

[0020] Figure 6 This is a light path diagram from the input end to the second output end during operation in the second embodiment of the present invention.

[0021] In the figure: 101, first single-fiber collimator; 102, first polarization beam splitter prism; 103, first half-wave plate; 104, Faraday rotator crystal; 105, second polarization beam splitter prism; 106, second single-fiber collimator; 107, third single-fiber collimator; 108, second half-wave plate; 109, third half-wave plate. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be another intermediate component through which it is fixed. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be another intermediate component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be another intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] First embodiment

[0026] See also Figures 1 to 3 , which is the first embodiment of the present application, a lossless switching magneto-optical switch includes a first single-fiber collimator 101, a first polarization beam splitter prism 102, a first half-wave plate 103, a Faraday rotator crystal 104, a second polarization beam splitter prism 105, a second single-fiber collimator 106, and a third single-fiber collimator 107, which are arranged in sequence.

[0027] The first single-fiber collimator 101 is used to collimate the incident light at the input end into a parallel light beam. The first single-fiber collimator 101 is located at the input end P1.

[0028] The first polarization beam splitter prism 102 includes two crystals, and the two crystals are coated at the bonding surface. Specifically, the two crystals of the first polarization beam splitter prism 102 are respectively a parallelogram crystal and a triangular crystal, and the parallelogram crystal and the triangular crystal are coated at the bonding surface, and the film reflects the s light and transmits the p light. The first polarization beam splitter prism 102 decomposes the parallel light input at the input end into two sub-beams of p light and s light with orthogonal polarization directions. At this time, the p light and the s light are the two main light paths. After being coated, the p light can be directly transmitted and transmitted along the lower light path. The s light is first reflected at the coating, and then undergoes total internal reflection at the interface between the parallelogram crystal and the external air, and is transmitted along the upper light path.

[0029] The first half-wave plate 103 rotates the polarization direction of the p-light by 135° clockwise along the optical transmission direction, and rotates the polarization direction of the s-light by 45° counterclockwise along the optical transmission direction.

[0030] Faraday rotator crystal 104 controls the operation of different channels of the magneto-optical switch by varying the polarity of the applied voltage, thereby changing the direction of the magnetic field. This Faraday rotator crystal 104 rotates the polarization of the two sub-beams in the main optical path. Due to the extinction ratio between the Faraday and wave plates, not all sub-beams are aligned in the ideal polarization state. Some very weak beams remain polarized, forming two weak optical paths.

[0031] The second polarization beam splitter prism 105 is used to combine light and comprises two crystals with a film coated at the joining surface of the two crystals. Specifically, the second polarization beam splitter prism 105 comprises two parallelogram crystals with a film coated at the joining surface of the two parallelogram crystals, and the film reflects the S light.

[0032] The second single fiber collimator 106 is located at the first output end P2, and the third single fiber collimator 107 is located at the first output end P3.

[0033] Please continue reading Figure 2When the magneto-optical switch is in the optical path from input terminal P1 to first output terminal P2, the working principle is as follows:

[0034] The divergent light beam output from the optical fiber (input end P1) is first collimated into a parallel beam by the first single-fiber collimator 101. After passing through the first polarization beam splitter prism 102, the parallel beam is split into two sub-beams, p-light and s-light, with orthogonal polarization directions. The p-light is directly transmitted after being coated and transmitted along the lower optical path. The s-light is first reflected by the coating, then undergoes total internal reflection at the interface between the parallelogram crystal and the external air, and is transmitted along the upper optical path. After passing through the first half-wave plate 103, the polarization direction of the p-light is rotated 135° clockwise along the optical path, while the polarization direction of the s-light is rotated 45° counterclockwise along the optical path. After passing through the Faraday rotator crystal 104, the polarization directions of the two sub-beams are rotated 45° clockwise along the optical path. At this time, the p-light and s-light emitted from the first polarization beam splitter prism 102 are still p-light and s-light, respectively. This portion of the optical path belongs to the main optical path. Due to the extinction ratio between Faraday and wave plates, not 100% of the sub-beams are concentrated in the ideal polarization state. There are also some very weak beams whose polarization directions have not rotated. This part of the beam is the p-light emitted from the first polarization splitter prism 102, which is changed into s-light, and the s-light is changed into p-light. This part of the light path belongs to the weak light path.

[0035] After passing through the second polarization beam splitter prism 105, the connection between the two parallelogram crystals is coated. The p-ray can be directly transmitted through the film, while the s-ray is reflected after passing through the film. In the main optical path, the p-ray first passes through the lower parallelogram crystal, undergoing total internal reflection at the interface between the parallelogram crystal and the external air. It then transmits through the thin film connecting the two parallelogram crystals. It then passes through the upper parallelogram crystal, undergoing total internal reflection at the interface between the parallelogram crystal and the external air, and finally transmits to the second single-fiber collimator 106 (i.e., the first output port P2). The s-ray first reflects from the thin film connecting the two parallelogram crystals, then passes through the upper parallelogram crystal, undergoing total internal reflection at the interface between the parallelogram crystal and the external air, and finally transmits to the second single-fiber collimator 106 (i.e., the first output port P2). In the weak light path, the p-light is directly transmitted through the thin film connecting the two parallelogram crystals and transmitted to the third single-fiber collimator 107 (i.e., the second output end P3); the s-light first passes through the parallelogram crystal below, undergoes total internal reflection at the interface between the parallelogram crystal and the external air, and then is reflected at the thin film connecting the two parallelogram crystals and transmitted to the third single-fiber collimator 107 (i.e., the second output end P3).

[0036] Please continue reading Figure 3When the magneto-optical switch is in the input end P1->second output end P3 optical path channel (main optical path): observed in the light transmission direction, when P1 to P3 are connected, the working principle is as follows:

[0037] The divergent light beam output from the optical fiber (input end P1) is first collimated into a parallel beam by the first single-fiber collimator 101. After passing through the first polarization beam splitter prism 102, the parallel beam is split into two sub-beams, p-light and s-light, with orthogonal polarization directions. The p-light is directly transmitted after being coated and transmitted along the lower optical path. The s-light is first reflected by the coating, then undergoes total internal reflection at the interface between the parallelogram crystal and the external air, and is transmitted along the upper optical path. After passing through the first half-wave plate 103, the polarization direction of the p-light is rotated 135° clockwise along the optical path, while the polarization direction of the s-light is rotated 45° counterclockwise along the optical path. After passing through the Faraday rotator crystal 104, the polarization directions of the two sub-beams are rotated 45° counterclockwise along the optical path. At this time, the light emitted from the first polarization beam splitter prism 102 is transformed into s-light, and the s-light is transformed into p-light. This portion of the optical path belongs to the main optical path. Due to the extinction ratio between Faraday and wave plates, not 100% of the sub-beams are concentrated in the ideal polarization state. There are also some very weak beams whose polarization directions have not rotated. This part of the beam is the p light emitted from the first polarization splitter prism 102, which is still p light and s light. This part of the light path belongs to the weak light path.

[0038] After passing through the second polarization beam splitter prism 105, the junction of the two parallelogram crystals is coated. This allows the p-ray to pass directly through the film, while the s-ray is reflected. In the main optical path, the p-ray is directly transmitted through the film connecting the two parallelogram crystals and transmitted to the third single-fiber collimator 107 (i.e., the second output port P3). The s-ray first passes through the lower parallelogram crystal, undergoes total internal reflection at the interface between the parallelogram crystal and the external air, and then reflects from the film connecting the two parallelogram crystals, transmitting to the third single-fiber collimator 107 (i.e., the second output port P3). In the weak light path, the p-light first passes through the parallelogram crystal below, undergoes total reflection at the interface between the parallelogram crystal and the external air, then transmits through the thin film connecting the two parallelogram crystals, then passes through the parallelogram crystal above, undergoes total reflection at the interface between the parallelogram crystal and the external air, and finally is transmitted to the second single-fiber collimator 106 (i.e., the first output end P2); the s-light first reflects at the thin film connecting the two parallelogram crystals, then passes through the parallelogram crystal above, undergoes total reflection at the interface between the parallelogram crystal and the external air, and finally is transmitted to the second single-fiber collimator 106 (i.e., the first output end P2).

[0039] Second embodiment

[0040] Please continue reading Figures 4 to 6 , which is the second embodiment of the present application, a lossless switching magneto-optical switch includes a first single-fiber collimator 101, a first polarization beam splitter prism 102, a second half-wave plate 108, a first half-wave plate 103, a Faraday rotator crystal 104, a third half-wave plate 109, a second polarization beam splitter prism 105, a second single-fiber collimator 106 and a third single-fiber collimator 107, which are arranged in sequence.

[0041] The first single-fiber collimator 101 is used to collimate the incident light at the input end into a parallel light beam. The first single-fiber collimator 101 is located at the input end P1.

[0042] The first polarization beam splitter prism 102 includes two crystals, and the two crystals are coated at the bonding surface. Specifically, the two crystals of the first polarization beam splitter prism 102 are respectively a parallelogram crystal and a triangular crystal, and the parallelogram crystal and the triangular crystal are coated at the bonding surface, and the film reflects the s light and transmits the p light. The first polarization beam splitter prism 102 decomposes the parallel light input at the input end into two sub-beams of p light and s light with orthogonal polarization directions. At this time, the p light and the s light are the two main light paths. After being coated, the p light can be directly transmitted and transmitted along the lower light path. The s light is first reflected at the coating, and then undergoes total internal reflection at the interface between the parallelogram crystal and the external air, and is transmitted along the upper light path.

[0043] The second half-wave plate 108 is located corresponding to the triangular crystal of the first polarization beam splitter prism 102 . The second half-wave plate 108 rotates the polarization direction of the p-light 90° counterclockwise along the optical transmission direction, and the p-light is converted into s-light.

[0044] The first half-wave plate 103 rotates the polarization direction of the s-light by 45° counterclockwise along the optical transmission direction.

[0045] Faraday rotator crystal 104 controls the operation of different channels of the magneto-optical switch by varying the polarity of the applied voltage, thereby changing the direction of the magnetic field. This Faraday rotator crystal 104 rotates the polarization of the two sub-beams in the main optical path. Due to the extinction ratio between the Faraday and wave plates, not all sub-beams are aligned in the ideal polarization state. Some very weak beams remain polarized, forming two weak optical paths.

[0046] The position of the third half-wave plate 109 corresponds to the quadrilateral crystal of the first polarization beam splitter prism 102. The third half-wave plate 109 rotates the s-light of the main light path 90° counterclockwise along the direction of light path propagation, and rotates the p-light of the weak light path 90° clockwise along the direction of light path propagation. At this time, the s-light in the upper main light path is converted into p-light, and the p-light in the weak light path is converted into s-light.

[0047] The second polarization beam splitter prism 105 is used to combine light and comprises two crystals with a film coated at the joining surface of the two crystals. Specifically, the second polarization beam splitter prism 105 comprises two parallelogram crystals with a film coated at the joining surface of the two parallelogram crystals, and the film reflects the S light.

[0048] The second single fiber collimator 106 is located at the first output end P2, and the third single fiber collimator 107 is located at the first output end P3.

[0049] Please continue reading Figure 5 When the magneto-optical switch is in the optical path from input terminal P1 to first output terminal P2, the working principle is as follows:

[0050] The divergent light beam output from the optical fiber (input end P1) is first collimated into a parallel beam by the first single-fiber collimator 101. After passing through the first polarization beam splitter prism 102, the parallel beam is split into two sub-beams, p-light and s-light, with orthogonal polarization directions. The p-light is directly transmitted after being coated and transmitted along the lower optical path. The s-light is first reflected by the coating, then undergoes total internal reflection at the interface between the parallelogram crystal and the external air, transmitting along the upper optical path. The second half-wave plate 108 is located in the lower optical path. Since the s-light does not pass through the second half-wave plate 108, it continues to propagate in the air medium. After passing through the second half-wave plate 108, the polarization direction of the p-light beam rotates 90° counterclockwise along the optical path, converting it to s-light. The sub-beams on both optical paths are s-light. After passing through the first half-wave plate 103, the polarization directions of the two sub-beams rotate 45° counterclockwise along the optical path. After passing through the Faraday rotator crystal 104, the polarization directions of the two sub-beams rotate 45° counterclockwise along the optical path, converting them from s-light to p-light. This portion of the optical path belongs to the main optical path. Due to the extinction ratio between the Faraday and wave plates, not 100% of the sub-beams are concentrated in the ideal polarization state. Some very weak beams remain s-light without polarization rotation, and this portion of the optical path belongs to the weak optical path. In the optical path above the third half-wave plate 109, the p-light beam below does not pass through the third half-wave plate 109 and continues to propagate through the air medium. The p light in the upper main light path rotates 90° clockwise along the light path propagation direction, and the s light in the weak light path rotates 90° counterclockwise along the light path propagation direction. At this time, the p light in the upper main light path is converted into s light, and the s light in the weak light path is converted into p light;

[0051] After passing through the second polarization beam splitter prism 105, the connection between the two parallelogram crystals is coated. The p-ray can be directly transmitted through the film, while the s-ray is reflected after passing through the film. In the main optical path, the p-ray first passes through the lower parallelogram crystal, undergoing total internal reflection at the interface between the parallelogram crystal and the external air. It then transmits through the thin film connecting the two parallelogram crystals. It then passes through the upper parallelogram crystal, undergoing total internal reflection at the interface between the parallelogram crystal and the external air, and finally transmits to the second single-fiber collimator 106 (i.e., the first output port P2). The s-ray first reflects from the thin film connecting the two parallelogram crystals, then passes through the upper parallelogram crystal, undergoing total internal reflection at the interface between the parallelogram crystal and the external air, and finally transmits to the second single-fiber collimator 106 (i.e., the first output port P2). In the weak light path, the p-light is directly transmitted through the thin film connecting the two parallelogram crystals and transmitted to the third single-fiber collimator 107 (i.e., the second output end P3); the s-light first passes through the parallelogram crystal below, undergoes total internal reflection at the interface between the parallelogram crystal and the external air, and then is reflected at the thin film connecting the two parallelogram crystals and transmitted to the third single-fiber collimator 107 (i.e., the second output end P3).

[0052] Please continue reading Figure 6 When the magneto-optical switch is in the input end P1->second output end P3 optical path channel (main optical path): observed in the light transmission direction, when P1 to P3 are connected, the working principle is as follows:

[0053] The divergent light beam output from the optical fiber (input end P1) is first collimated into a parallel beam by the first single-fiber collimator 101. After passing through the first polarization beam splitter prism 102, the parallel beam is split into two sub-beams, p-light and s-light, with orthogonal polarization directions. The p-light is directly transmitted after being coated and transmitted along the lower optical path. The s-light is first reflected by the coating, then undergoes total internal reflection at the interface between the parallelogram crystal and the external air, transmitting along the upper optical path. The second half-wave plate 108 is located in the lower optical path. Since the s-light does not pass through the second half-wave plate 108, it continues to propagate in the air medium. After the p-light passes through the second half-wave plate 108, its polarization direction rotates 90° counterclockwise along the optical path, converting it into s-light. The sub-beams on both optical paths are now s-light. After passing through the first half-wave plate 103, the polarization directions of the two sub-beams rotate 45° counterclockwise along the optical path. After passing through the Faraday rotator crystal 104, the polarization directions of the two sub-beams rotate 45° clockwise along the optical path. At this point, the two sub-beams remain s-light, and this portion of the optical path belongs to the main optical path. Due to the extinction ratio between the Faraday and wave plates, not 100% of the sub-beams are concentrated in the ideal polarization state. Some very weak beams remain polarized without any rotation. These beams are converted from s-light to p-light, and this portion of the optical path belongs to the weak optical path.

[0054] In the upper optical path of the third half-wave plate 109, the s-light in the lower direction does not pass through the third half-wave plate 109 and continues to propagate through the air. The s-light in the upper main optical path rotates 90° counterclockwise along the optical path propagation direction, while the p-light in the weak optical path rotates 90° clockwise along the optical path propagation direction. At this time, the s-light in the upper main optical path is converted to p-light, and the p-light in the weak optical path is converted to s-light.

[0055] After passing through the second polarization beam splitter prism 105, the junction of the two parallelogram crystals is coated. This allows the p-ray to pass directly through the film, while the s-ray is reflected. In the main optical path, the p-ray is directly transmitted through the film connecting the two parallelogram crystals and transmitted to the third single-fiber collimator 107 (i.e., the second output port P3). The s-ray first passes through the lower parallelogram crystal, undergoes total internal reflection at the interface between the parallelogram crystal and the external air, and then reflects from the film connecting the two parallelogram crystals, transmitting to the third single-fiber collimator 107 (i.e., the second output port P3). In the weak light path, the p-light first passes through the parallelogram crystal below, undergoes total reflection at the interface between the parallelogram crystal and the external air, then transmits through the thin film connecting the two parallelogram crystals, then passes through the parallelogram crystal above, undergoes total reflection at the interface between the parallelogram crystal and the external air, and finally is transmitted to the second single-fiber collimator 106 (i.e., the first output end P2); the s-light first reflects at the thin film connecting the two parallelogram crystals, then passes through the parallelogram crystal above, undergoes total reflection at the interface between the parallelogram crystal and the external air, and finally is transmitted to the second single-fiber collimator 106 (i.e., the first output end P2).

[0056] As can be seen from the above principle, when the optical channel is switched, it is essentially the exchange of the intensity of the strong light and weak light paths. After deducting the material absorption, material reflectivity loss and coupling loss between parts, theoretically the sum of the energy of the two is equal to the input light energy. This solution couples both strong light and weak light into different channels (the magneto-optical switches currently on the market only couple strong light channels, not weak light channels). When the switch is switched, it actually takes a certain response time to complete the switch. During the time when the switch starts but is not completed, the energy of the weak light increases when the energy is converted between the strong light and the weak light. However, since the conventional magneto-optical switch does not couple the weak light channel, instability occurs in the system, and it will not stabilize until all switches are completed). In this invention, the sum of the energy at the P2+P3 channel and the sum of the energy of the P2+P3 channel after the switch is completed are always in a stable state, which brings stability to the network transmission.

[0057] This application achieves lossless switching of a magneto-optical switch. By cleverly arranging polarization beam splitters and utilizing half-wave plates and Faraday rotator crystals to alter the polarization direction of the light beams, this ensures that all light beams are accurately converged at the output port after passing through the second polarization beam splitter prism 105. This design significantly reduces optical energy loss during the optical switch switching process, ensuring that the sum of the optical energy output from the two ports of the magneto-optical switch remains constant throughout the entire switching process, both at the moment of switching and after the switch is complete. This design significantly reduces energy loss during the magneto-optical switch switching process, providing a high degree of stability for the optical transmission system.

[0058] The above embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patented invention. It should be noted that those skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention. These variations and improvements are equivalent modifications and improvements to the above embodiments based on the essential technology of the present invention and fall within the scope of protection of the present invention.

Claims

1. A magneto-optical switch for lossless switching, comprising an input terminal, a first output terminal, and a second output terminal, characterized in that: The lossless switching magneto-optical switch further includes a first polarization beam splitter prism, a first half-wave plate, a Faraday rotator crystal, and a second polarization beam splitter prism, which are arranged in sequence. The input end is located on the side of the first polarization beam splitter prism away from the first half-wave plate, and the first output end and the second output end are located on the side of the second polarization beam splitter prism away from the Faraday rotator crystal. The first polarization beam splitter prism and the second polarization beam splitter prism each include two crystals, and the two crystals are coated at the junction. The lossless switching magneto-optical switch further includes a second half-wave plate and a third half-wave plate. The second half-wave plate is located between the first polarization beam splitter prism and the first half-wave plate, and the second half-wave plate is located on the p-light channel emitted from the first polarization beam splitter prism. The third half-wave plate is located between the Faraday rotator crystal and the second polarization beam splitter prism. The third half-wave plate is located on the s light channel emitted from the first polarization beam splitter prism. The first polarization beam splitter prism decomposes the parallel light input from the input end into two sub-beams p light and s light with orthogonal polarization directions. The p light and the s light form two main light paths. The first half-wave plate can rotate the polarization direction of the p light by 135° clockwise along the direction of light path transmission and the polarization direction of the s light by 45° counterclockwise along the direction of light path transmission. The Faraday rotator crystal rotates the main light path by 45° clockwise or 45° counterclockwise by applying magnetic fields in different directions. At the same time, the polarization direction of a very weak light beam is not rotated to produce two weak light paths. The second polarization beam splitter prism converges the p light and s light of the two main light paths to one of the first output end and the second output end, and converges the p light and s light of the two weak light paths to the other of the second output end and the first output end.

2. The magneto-optical switch for lossless switching according to claim 1, characterized in that: The two crystals of the first polarization beam splitter prism are a parallelogram crystal and a triangular crystal, and the mating surfaces of the parallelogram crystal and the triangular crystal are coated to reflect s light and transmit p light.

3. The magneto-optical switch for lossless switching according to claim 2, characterized in that: The two crystals of the second polarization beam splitter are two parallelogram crystals, and the bonding surfaces of the two parallelogram crystals are coated to reflect the S light.

4. The magneto-optical switch for lossless switching according to claim 3, characterized in that: The position of the second half-wave plate corresponds to the triangular crystal of the first polarization beam splitter prism, and the position of the third half-wave plate corresponds to the parallelogram crystal of the first polarization beam splitter prism.

5. The magneto-optical switch for lossless switching according to claim 1, characterized in that: The lossless switching magneto-optical switch further includes a first single-fiber collimator, which is located at the input end and collimates the divergent light beam output by the optical fiber into a parallel light beam.

6. The magneto-optical switch for lossless switching according to claim 5, characterized in that: The lossless switching magneto-optical switch further includes a second single-fiber collimator and a third single-fiber collimator, and the second single-fiber collimator and the third single-fiber collimator are respectively located at the first output end and the second output end.

7. The magneto-optical switch for lossless switching according to claim 6, characterized in that: The parallel light beam emitted by the first single-fiber collimator, the light beam received by the second single-fiber collimator, and the light beam received by the third single-fiber collimator are parallel to each other.

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