Magneto-optical switch based on single coil

Abstract

The utility model relates to a magneto-optical switch based on a single coil. The magneto-optical switch comprises a first displacement sheet, a first optical rotation assembly, a second optical rotation assembly, a roof prism, a third optical rotation assembly and a second displacement sheet which are arranged along an optical path. The second optical rotation assembly comprises a second magneto-optical thin film crystal, a PBS assembly and a third magneto-optical thin film crystal which are arranged in the magnetic element along the optical path. According to the utility model, the second magneto-optical film crystal, the PBS assembly and the third magneto-optical film crystal are usually arranged in a single coil, and the single coil can be utilized to realize magnetic field conversion of two magnetizing magneto-optical materials at the same time. Finally, one coil is realized, and the magneto-optical switch with two-stage isolation is realized. However, in the prior art, a two-stage isolation structure can be realized only by using two coils; according to the utility model, the PBS assembly can realize the separation of two polarization light beams on the size of 0.5 * 1.0 * 1.0 mm. Magnetic field switching of two pieces of magnetizing type magneto-optical materials in one coil is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, in particular to a magneto-optical switch based on a single coil. Background Art

[0002] The magneto-optical switch is an optical switch that uses the Faraday rotation effect to change the polarization plane of light. The principle is to change the effect of the magneto-optical crystal on the polarization plane of incident polarized light by changing the external magnetic field, and finally achieve the effect of switching the optical path. This switch is widely used in optical fiber transmission systems, especially in polarization-maintaining optical fiber transmission systems, where the role of magneto-optical switches is particularly important.

[0003] Magneto-optical switches have no moving parts, fast response speed, and low control voltage, which have obvious advantages. Ordinary magneto-optical switches generally use birefringent crystals for parallel splitting, and change the polarization state of the light beam to switch the optical signal between two parallel optical paths. However, the cost of the birefringent crystals used in this type of solution is relatively high, and the birefringent crystal splitting distance is limited. In order to separate the two light spots sufficiently, parallel splitting requires the use of fiber beam expansion and other technologies to reduce the light spot or lengthen the length of the birefringent crystal. The technical route is complex and the cost is relatively high. In addition, the optical path of this solution is also relatively complex, and the debugging difficulty is relatively high.

[0004] How to use polarization beam splitter prism to replace birefringent crystal to make magneto-optical switch and reduce material cost is a technical problem to be solved. If polarization beam splitter prism can be used to replace birefringent crystal, the cost and debugging difficulty will be greatly reduced, and there will be no problems of moving parts and slow response speed.

[0005] The magneto-optical switches manufactured by current technology are usually large in size, which makes it difficult to meet the current demand for ultra-small size. Future research still needs to solve these problems to make the magneto-optical switch smaller so as to better adapt to practical applications and various application scenarios. Utility Model Content

[0006] In order to solve the above problems in the prior art, the utility model provides a magneto-optical switch based on a single coil.

[0007] In order to achieve the above-mentioned purpose, the main technical solutions adopted by the utility model include:

[0008] A magneto-optical switch based on a single coil comprises a first displacement plate, a first optical rotation component, a second optical rotation component, a roof prism, a third optical rotation component and a second displacement plate arranged along an optical path; the second optical rotation component comprises a second magneto-optical thin film crystal, a PBS component and a third magneto-optical thin film crystal arranged along the optical path in a magnetic element.

[0009] Furthermore, the first optical rotation component includes a first 45° wave plate and a first magneto-optical thin film crystal arranged along the optical path; the third optical rotation component includes a fourth magneto-optical thin film crystal and a second 45° wave plate arranged along the optical path; the first 45° wave plate and the second 45° wave plate are respectively arranged on optical paths of different polarized lights.

[0010] Further, the first optical rotation component includes a first 22.5° wave plate and a second 22.5° wave plate arranged along the optical path; the third optical rotation component includes a third 22.5° wave plate and a fourth 22.5° wave plate arranged along the optical path; the first 22.5° wave plate and the second 22.5° wave plate are respectively arranged on optical paths of different polarized lights, and rotate the polarized lights in opposite directions; the third 22.5° wave plate and the fourth 22.5° wave plate are respectively arranged on optical paths of different polarized lights, and rotate the polarized lights in opposite directions.

[0011] Furthermore, the PBS component includes a reflection surface parallel to the polarization splitting surface.

[0012] Furthermore, the first magneto-optical thin film crystal is a GSF magneto-optical thin film crystal; and the fourth magneto-optical thin film crystal is a GSF magneto-optical thin film crystal.

[0013] Furthermore, the second magneto-optical thin film crystal and the third magneto-optical thin film crystal are GMF magneto-optical thin film crystals.

[0014] Furthermore, the magnetic element is a state latching electromagnet.

[0015] Furthermore, the magnetic element is a single coil.

[0016] The beneficial effects of the utility model are as follows: the second magneto-optical film crystal, the PBS component, and the third magneto-optical film crystal are usually arranged in a single coil, and the single coil can be used to simultaneously realize magnetic field conversion for two magnetized magneto-optical materials. Finally, one coil is realized to realize a magneto-optical switch with a double-stage isolation degree; in the prior art, two coils are usually required to realize a double-stage isolation structure; in the structure of the utility model, the PBS component can realize the separation of two polarization state light beams in a size of 0.5x1.0x1.0mm. Thus, it is possible to realize magnetic field switching of two magnetized magneto-optical materials in one coil. The PBS component includes a reflection surface parallel to the polarization splitting surface, so as to ensure that the reflected light can be reflected by the reflection surface and then emitted in parallel with the outgoing light. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the implementation mode of the utility model, the drawings required for use in the implementation mode will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a schematic diagram of the structure of the first embodiment of the utility model;

[0019] Figure 2 This is another optical path schematic diagram of the first embodiment of the utility model;

[0020] Figure 3 This is a schematic diagram of the structure of the second embodiment of the utility model;

[0021] Figure 4 This is another optical path schematic diagram of the second embodiment of the utility model;

[0022] Figure 5 This is a schematic diagram of the optical path of the PBS component of the utility model;

[0023] Description of reference numerals:

[0024] 100, first displacement plate; 101, first collimator; 200, first optical rotation component; 210, first 45° wave plate; 220, first magneto-optical thin film crystal; 201, first 22.5° wave plate; 202, second 22.5° wave plate; 300, second optical rotation component; 310, second magneto-optical thin film crystal; 320, PBS component; 321, polarization splitter surface; 322, reflection surface; 330, third magneto-optical thin film crystal; 340, magnetic element; 400, third optical rotation component; 410, fourth magneto-optical thin film crystal; 420, second 45° wave plate; 401, third 22.5° wave plate; 402, fourth 22.5° wave plate; 500, second displacement plate; 501, second collimator; 600, roof prism. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the utility model for which protection is sought, but merely represents the selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0026] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] Example 1, please refer to Figure 1 As shown:

[0029] A magneto-optical switch based on a single coil comprises a first displacement plate 100, a first optical rotation component 200, a second optical rotation component 300, a roof prism 600, a third optical rotation component 400, and a second displacement plate 500 arranged along an optical path;

[0030] The first displacement plate 100 and the second displacement plate 500 are used to decompose the input light in any state into two polarization components with perpendicular polarization directions or to combine the two polarization components with perpendicular polarization directions into one light beam;

[0031] The first optical rotation component 200 includes a first 45° wave plate 210 and a first magneto-optical thin film crystal 220 arranged along the optical path;

[0032] The second optical rotation component 300 includes a second magneto-optical thin film crystal 310, a PBS component 320, and a third magneto-optical thin film crystal 330 arranged along the optical path in a magnetic element 340;

[0033] The third optical rotation component 400 includes a fourth magneto-optical thin film crystal 410 and a second 45° wave plate 420 arranged along the optical path;

[0034] The first 45° wave plate 210 and the second 45° wave plate 420 are respectively arranged on optical paths of different polarized lights;

[0035] The first magneto-optical film crystal 220 and the fourth magneto-optical film crystal 410 are GSF magneto-optical film crystals; the first magneto-optical film crystal 220 and the fourth magneto-optical film crystal 410 can use crystals with fixed magnetism, which can make the incident line polarization produce a 45° flip in the same direction without adding an external magnetic field;

[0036] The second magneto-optical film crystal 310 and the third magneto-optical film crystal 330 are GMF magneto-optical film crystals, and the magnetic element 340 is a state latching electromagnet or a single coil, which can generate an external positive saturation magnetic field or maintain an external positive saturation magnetic field or generate an external reverse saturation magnetic field or maintain an external reverse saturation magnetic field for the second magneto-optical film crystal 310 and the third magneto-optical film crystal 330. Under the action of the external positive saturation magnetic field, the optical rotation angle of the second magneto-optical film crystal 310 and the third magneto-optical film crystal 330 is 45° in the positive direction, and under the action of the external reverse saturation magnetic field, the optical rotation angle of the second magneto-optical film crystal 310 and the third magneto-optical film crystal 330 is 45° in the reverse direction.

[0037] The second magneto-optical thin film crystal 310, the PBS component 320, and the third magneto-optical thin film crystal 330 are usually arranged in a single coil, and the single coil can be used to simultaneously realize magnetic field conversion for two pieces of magnetized magneto-optical materials. Finally, one coil is realized to realize a magneto-optical switch with a dual-stage isolation; in the prior art, two coils are usually required to realize a dual-stage isolation structure; in the structure of the utility model, the PBS component 320 can realize the separation of two polarization light beams in a size of 0.5x1.0x1.0mm. Thereby, it is possible to realize magnetic field switching of two pieces of magnetized magneto-optical materials in one coil. The PBS component 320 includes a reflection surface 322 parallel to the polarization splitting surface 321, so as to ensure that the reflected light can be reflected by the reflection surface and then emitted in parallel with the outgoing light;

[0038] The first displacement plate 100 generally further includes a first collimator 101, which collimates the incident light and couples it into the first displacement plate 100; finally, after being combined by the second displacement plate 500, the incident light is coupled into the second collimator 501 behind the second displacement plate 500 for output;

[0039] See also Figure 1 , the input light is defined to include polarized light A1 and polarized light A2 whose polarization states are perpendicular to each other, see Figure 1 As shown in s1, the polarized light is transmitted in the forward direction along the optical path. After passing through the first displacement plate 100, the polarized light is decomposed into two polarized light beams A1 and A2 with perpendicular polarization directions. Figure 1 As shown in s2; since the first 45° wave plate 210 and the second 45° wave plate 420 are respectively arranged on the optical paths of different polarized lights, the first 45° wave plate 210 is arranged on the optical path of polarized light A1, at this time, polarized light A1 rotates 90° after passing through the first 45° wave plate 210, and the polarization state is shown in FIG. Figure 1 As shown in s3; after further passing through the first magneto-optical thin film crystal 220, the polarization state is shown in Figure 1 As shown in s4; further entering the second optical rotation component 300, in this embodiment, the magnetic element 340 generates an external positive saturation magnetic field, the optical rotation angle of the second magneto-optical thin film crystal 310 and the third magneto-optical thin film crystal 330 is positive 45°, and the polarization state of the two polarized light beams after passing through the second magneto-optical thin film crystal 310 is as shown Figure 1 As shown in s5, it can be transmitted from the polarization splitting surface 321 in the PBS component 320 and enter the third magneto-optical thin film crystal 330. The polarization state of the polarized light emitted from the PBS component 320 is shown in FIG. Figure 1 Further, the polarization state after passing through the third magneto-optical thin film crystal 330 is shown in FIG. Figure 1 Further, the polarization state after passing through the fourth magneto-optical thin film crystal 410 is shown in FIG. Figure 1 As shown in S8; the second 45° wave plate 420 is disposed on the optical path of the polarized light A2. At this time, the polarized light A2 is rotated 90° after passing through the second 45° wave plate 420. The polarization state is shown in FIG. Figure 1 As shown in s9, Figure 1 The dotted line on the left side of the second 45° wave plate 420 is for easy understanding that the second 45° wave plate 420 is set on the optical path of the polarized light A2, and the dotted line position is empty, and the polarization state and other characteristics of the polarized light A1 are not changed; finally, the two polarized lights pass through the second displacement plate 500 and are combined and output;

[0040] The polarization state of polarized light in the reverse light path, see Figure 1As shown in s11-s20; the polarization state schematic diagrams s1-s20 all indicate the polarization state after passing through a certain component, the dotted line in the polarization state schematic diagrams s1-s10 on the right side of a certain component indicates the polarization state of polarized light after passing through a certain component in the forward light path; the dotted line in the polarization state schematic diagrams s11-s20 on the left side of a certain component indicates the polarization state of polarized light after passing through a certain component in the reverse light path;

[0041] See also Figure 2 In this embodiment, the structure of the magneto-optical switch is Figure 1 The embodiment shown is the same, the difference is that the magnetic element 340 generates an external reverse saturation magnetic field, the second magneto-optical thin film crystal 310 and the third magneto-optical thin film crystal 330 have an optical rotation angle of 45° in the opposite direction, and the polarization state of the two polarized light beams after passing through the second magneto-optical thin film crystal 310 is as follows Figure 2 As shown in s25, it cannot be transmitted from the polarization splitting surface 321 in the PBS component 320, but will be reflected by the polarization splitting surface 321 and enter the reflection surface 322. After being reflected by the reflection surface 322, it can enter the third magneto-optical thin film crystal 330 from the PBS component 320. The polarization state of the polarized light emitted from the PBS component 320 is shown in FIG. Figure 1 As shown in s26, the position of the polarized light output after reflection has changed (see Figure 5 As shown), the combined light beam output from the second displacement plate 500 is located in different channels; the polarization state of the polarized light in the subsequent optical path is shown in Figure 2 As shown in s27-s30;

[0042] The polarization state of polarized light in the reverse light path, see Figure 2 Similarly, the polarization state after passing through the third magneto-optical thin film crystal 330 is as shown in Figure 2 As shown in s35 in the figure, it is first reflected by the reflection surface 322 and then enters the polarization splitting surface 321. However, the polarized light in this polarization state cannot be transmitted from the polarization splitting surface 321 in the PBS component 320, and will be reflected by the polarization splitting surface 321 to enter the original optical path and continue to transmit.

[0043] Therefore, in this embodiment, by changing the direction of the saturation magnetic field generated by the magnetic element 340, the output light of different channels can be achieved; the second collimator 501 can use a dual-fiber collimator to couple different output channels respectively or set two second collimators to couple different output channels respectively; in this embodiment, the optical path is reversible.

[0044] Example 2, see Figure 3 As shown,

[0045] A magneto-optical switch based on a single coil comprises a first displacement plate 100, a first optical rotation component 200, a second optical rotation component 300, a roof prism 600, a third optical rotation component 400, and a second displacement plate 500 arranged along an optical path;

[0046] The first optical rotation component 200 includes a first 22.5° wave plate 201 and a second 22.5° wave plate 202 arranged along the optical path;

[0047] The second optical rotation component 300 includes a second magneto-optical thin film crystal 310, a PBS component 320, and a third magneto-optical thin film crystal 330 arranged along the optical path in a magnetic element 340;

[0048] The third optical rotation component 400 includes a third 22.5° wave plate 401 and a fourth 22.5° wave plate 402 arranged along the optical path;

[0049] The first 22.5° wave plate 201 and the second 22.5° wave plate 202 are respectively arranged on optical paths of different polarized lights, and rotate the polarized lights in opposite directions;

[0050] The third 22.5° wave plate 401 and the fourth 22.5° wave plate 402 are respectively arranged on the optical paths of different polarized lights, and rotate the polarized lights in opposite directions;

[0051] The first displacement plate 100 generally further includes a first collimator 101, which collimates the incident light and couples it into the first displacement plate 100; finally, after being combined by the second displacement plate 500, the incident light is coupled into the second collimator 501 behind the second displacement plate 500 for output;

[0052] See also Figure 3 , the input light is defined to include polarized light A1 and polarized light A2 whose polarization states are perpendicular to each other, see Figure 3 As shown in s41, the polarized light is transmitted in the forward direction along the optical path. After passing through the first displacement plate 100, the polarized light is decomposed into two polarized light beams A1 and A2 with perpendicular polarization directions. Figure 3 As shown in s42; since the first 22.5° wave plate 201 and the second 22.5° wave plate 202 are respectively arranged on the optical paths of different polarized lights, and the rotation directions of the polarized lights are opposite, the first 22.5° wave plate 201 is arranged on the optical path of polarized light A1, and the second 22.5° wave plate 202 is arranged on the optical path of polarized light A2, the polarization state of the polarized light after passing through the first optical rotation component 200 is shown in FIG. Figure 3As shown in s43; further entering the second optical rotation component 300, in this embodiment, the magnetic element 340 generates an external positive saturation magnetic field, the optical rotation angle of the second magneto-optical thin film crystal 310 and the third magneto-optical thin film crystal 330 is positive 45°, and the polarization state of the two polarized light beams after passing through the second magneto-optical thin film crystal 310 is as follows Figure 3 As shown in s44, it can be transmitted from the polarization splitting surface 321 in the PBS component 320 and enter the third magneto-optical thin film crystal 330. The polarization state of the polarized light emitted from the PBS component 320 is shown in FIG. Figure 3 Further, the polarization state after passing through the third magneto-optical thin film crystal 330 is shown in FIG. Figure 3 As shown in s46; the third 22.5° wave plate 401 and the fourth 22.5° wave plate 402 are respectively arranged on the optical paths of different polarized lights, and the rotation directions of the polarized lights are opposite. The third 22.5° wave plate 401 is arranged on the optical path of polarized light A1, and the fourth 22.5° wave plate 402 is arranged on the optical path of polarized light A2. The polarization state of the polarized light after passing through the third optical rotation component 400 is shown in FIG. Figure 3 As shown in s47; finally, the two polarized light beams pass through the second displacement plate 500 and are combined and output;

[0053] The polarization state of polarized light in the reverse light path, see Figure 3 In the reverse optical path, the polarization state after passing through the third magneto-optical thin film crystal 330 is shown in FIG. Figure 3 As shown in s52, the two polarized lights in this polarization state cannot be transmitted from the polarization splitting surface 321 in the PBS component 320, but will be reflected by the polarization splitting surface 321 and emitted downward, so that they cannot further return along the original light path, thereby achieving the isolation effect of the reverse light path;

[0054] See also Figure 4 In this embodiment, the structure of the magneto-optical switch is Figure 3 The embodiment shown is the same, the difference is that the magnetic element 340 generates an external reverse saturation magnetic field, the second magneto-optical thin film crystal 310 and the third magneto-optical thin film crystal 330 have an optical rotation angle of 45° in the opposite direction, and the polarization state of the two polarized light beams after passing through the second magneto-optical thin film crystal 310 is as follows Figure 4 As shown in s64, it cannot be transmitted from the polarization splitting surface 321 in the PBS component 320, but will be reflected by the polarization splitting surface 321 and enter the reflection surface 322. After being reflected by the reflection surface 322, it can enter the third magneto-optical thin film crystal 330 from the PBS component 320. The polarization state of the polarized light emitted from the PBS component 320 is shown in FIG. Figure 4 As shown in s65, the position of the polarized light output after reflection has changed (see Figure 5As shown), the combined light beam output from the second displacement plate 500 is located in different channels; the polarization state of the polarized light in the subsequent optical path is shown in Figure 4 As shown in s66-s68;

[0055] The polarization state of polarized light in the reverse light path, see Figure 4 In the reverse optical path, the polarization state after passing through the third magneto-optical thin film crystal 330 is shown in FIG. Figure 4 As shown in s72, it is first reflected by the reflection surface 322 and then enters the polarization splitting surface 321, and the polarized light in this polarization state will be transmitted from the polarization splitting surface 321 in the PBS component 320 and then emitted downward, so that it cannot further return along the original light path, thereby achieving the isolation effect of the reverse light path;

[0056] Therefore, in this embodiment, by changing the direction of the saturation magnetic field generated by the magnetic element 340, the output light of different channels can be achieved; the second collimator 501 can use a dual-fiber collimator to couple different output channels respectively or set two second collimators 501 to couple different output channels respectively; at the same time, in this embodiment, the reflected light can also be isolated.

[0057] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A magneto-optical switch based on a single coil, characterized in that: It includes a first displacement plate, a first optical rotation component, a second optical rotation component, a roof prism, a third optical rotation component, and a second displacement plate arranged along the optical path; the second optical rotation component includes a second magneto-optical film crystal, a PBS component, and a third magneto-optical film crystal arranged along the optical path in the magnetic element.

2. A magneto-optical switch based on a single coil according to claim 1, characterized in that: The first optical rotation component includes a first 45° wave plate and a first magneto-optical thin film crystal arranged along the optical path; the third optical rotation component includes a fourth magneto-optical thin film crystal and a second 45° wave plate arranged along the optical path; the first 45° wave plate and the second 45° wave plate are respectively arranged on optical paths of different polarized lights.

3. A single-coil magneto-optical switch according to claim 1, characterized in that: The first optical rotation component includes a first 22.5° wave plate and a second 22.5° wave plate arranged along the optical path; the third optical rotation component includes a third 22.5° wave plate and a fourth 22.5° wave plate arranged along the optical path; the first 22.5° wave plate and the second 22.5° wave plate are respectively arranged on optical paths of different polarized lights, and rotate the polarized lights in opposite directions; the third 22.5° wave plate and the fourth 22.5° wave plate are respectively arranged on optical paths of different polarized lights, and rotate the polarized lights in opposite directions.

4. A single-coil magneto-optical switch according to claim 1, characterized in that: The PBS component includes a reflection surface parallel to the polarization splitting surface.

5. The single-coil magneto-optical switch according to claim 2, characterized in that: The first magneto-optical thin film crystal is a GSF magneto-optical thin film crystal; the fourth magneto-optical thin film crystal is a GSF magneto-optical thin film crystal.

6. The single-coil magneto-optical switch according to claim 1, characterized in that: The second magneto-optical thin film crystal and the third magneto-optical thin film crystal are GMF magneto-optical thin film crystals.

7. The single-coil magneto-optical switch according to claim 1, characterized in that: The magnetic element is a state latching electromagnet.

8. The magneto-optical switch based on a single coil according to claim 1, characterized in that: The magnetic element is a single coil.

Images