2*2 magneto-optical switch

Abstract

The utility model relates to a 2 * 2 magneto-optical switch which comprises a first double-fiber collimator, a first birefringent crystal wedge angle sheet pair, an optical rotation assembly, a wave plate, a second birefringent crystal wedge angle sheet pair and a second double-fiber collimator which are sequentially arranged from left to right. The first double-fiber collimator comprises a first optical fiber and a second optical fiber; the second double-fiber collimator comprises a third optical fiber and a fourth optical fiber; the light beam of the first optical fiber is coupled into the third optical fiber and the light beam of the second optical fiber is coupled into the fourth optical fiber, or the light beam of the first optical fiber is coupled into the fourth optical fiber and the light beam of the second optical fiber is coupled into the third optical fiber. The optical fiber filter is small in size, low in insertion loss and high in extinction ratio; and assembling and debugging are simple.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, in particular to a 2x2 magneto-optical switch. 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] 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

[0005] In order to solve the above problems in the prior art, the utility model provides a 2x2 magneto-optical switch.

[0006] In order to achieve the above-mentioned purpose, the main technical solutions adopted by the utility model include:

[0007] A 2x2 magneto-optical switch comprises a first dual-fiber collimator, a first birefringent crystal wedge pair, an optical rotation component, a wave plate, a second birefringent crystal wedge pair, and a second dual-fiber collimator which are arranged in sequence from left to right; the first dual-fiber collimator comprises a first optical fiber and a second optical fiber; the second dual-fiber collimator comprises a third optical fiber and a fourth optical fiber; the light beam of the first optical fiber is coupled into the third optical fiber, and the light beam of the second optical fiber is coupled into the fourth optical fiber, or the light beam of the first optical fiber is coupled into the fourth optical fiber, and the light beam of the second optical fiber is coupled into the third optical fiber.

[0008] Furthermore, the first birefringent crystal wedge plate pair and the second birefringent crystal wedge plate pair are Wollaston prisms.

[0009] Furthermore, the optical rotation component includes a magneto-optical crystal arranged in a magnetic element; the magnetic element generates positive and negative magnetic fields according to the direction of power supply to control the optical rotation direction of the magneto-optical crystal to be positive or reverse.

[0010] Furthermore, the magnetic element is a single coil.

[0011] Furthermore, the wave plate is a 22.5° wave plate.

[0012] Furthermore, the optical rotation angle of the magneto-optical crystal is 45°.

[0013] Furthermore, the collimation length of the first dual-fiber collimator matches the collimation length of the second dual-fiber collimator to ensure minimum insertion loss.

[0014] Furthermore, the first birefringent crystal wedge pair, the optical rotation assembly, the wave plate, and the second birefringent crystal wedge pair are assembled together using optical adhesive.

[0015] Furthermore, the first dual-fiber collimator and the second dual-fiber collimator are both polarization-maintaining dual-fiber collimators.

[0016] The utility model has the following beneficial effects: small volume, low insertion loss, high extinction ratio and simple assembly and debugging. 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 It is a schematic diagram of the structure of the utility model;

[0019] Figure 2 This is a polarization schematic diagram of the coil of the utility model when a forward current is passed through it;

[0020] Figure 3 This is a schematic diagram of polarization when a reverse current flows through the coil of the utility model;

[0021] Figure 4 This is a polarization diagram of a novel coil in another embodiment of the utility model when a forward current is passed through it;

[0022] Figure 5 This is a polarization diagram of a novel coil in another embodiment of the utility model when a reverse current is passed through it;

[0023] Description of reference numerals:

[0024] 100. a first dual-fiber collimator; 110. a first optical fiber; 120. a second optical fiber; 210. a first birefringent crystal wedge pair; 220. a magneto-optical crystal; 230. a wave plate; 240. a magnetic element; 250. a second birefringent crystal wedge pair; 300. a second dual-fiber collimator; 310. a third optical fiber; 320. a fourth optical fiber. 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] like Figure 1As shown, a 2x2 magneto-optical switch includes a first dual-fiber collimator 100, a first birefringent crystal wedge plate pair 210, an optical rotation component, a wave plate 230, a second birefringent crystal wedge plate pair 250, and a second dual-fiber collimator 300, which are arranged from left to right in sequence; the wave plate 230 is a 22.5° wave plate 230; the first dual-fiber collimator 100 includes a first optical fiber 110 and a second optical fiber 120; the second dual-fiber collimator 300 includes a third optical fiber 310 and a fourth optical fiber 320; the light beam of the first optical fiber 110 is coupled into the third optical fiber 310, and the light beam of the second optical fiber 120 is coupled into the fourth optical fiber 320, or the light beam of the first optical fiber 110 is coupled into the fourth optical fiber 320 and the second optical fiber 120. The light beam of 120 is coupled into the third optical fiber 310; the first birefringent crystal wedge plate pair 210 and the second birefringent crystal wedge plate pair 250 are Wollaston prisms; the Wollaston prism is formed by gluing two uniaxial birefringent right-angle prisms with the same bottom surface and orthogonal optical axes, and the incident light is vertically incident on the end face of the prism. The incident light is linearly polarized light. The use of two birefringent right-angle prisms can play a role in carding the polarization state and provide an extinction ratio; the optical rotation component includes a magneto-optical crystal 220 arranged in a magnetic element 240; the magnetic element 240 generates a positive and negative magnetic field according to the direction of power on to control the optical rotation direction of the magneto-optical crystal 220 to be forward or reverse; the optical rotation angle of the magneto-optical crystal 220 is 45°; the magnetic element 240 is preferably a single coil;

[0029] like Figure 2 As shown, when a forward current is passed through the magnetic element 240 (one direction is defined as the forward direction and the other direction is defined as the reverse direction), a forward magnetic field is generated. At this time, the magneto-optical crystal 220 in the magnetic field of the magnetic element 240 can rotate the polarized light passing through by 45° (+45°) clockwise. The propagation direction from the first optical fiber 110 to the third optical fiber 310 and from the second optical fiber 120 to the fourth optical fiber 320 is analyzed and recorded as the forward propagation direction; the input light in the first optical fiber 110 is defined to include polarized light B1 and polarized light B2 whose polarization states are perpendicular to each other, and the input light in the second optical fiber 120 is defined to include polarized light A1 and polarized light A2 whose polarization states are perpendicular to each other, see Figure 2 As shown in s11, the polarized light is transmitted in the forward direction along the optical path. After passing through the first birefringent crystal wedge plate pair 210, the polarized light is decomposed into polarized light A1, A2 and B1, B2 with perpendicular polarization directions. Figure 2 As shown in s12; the polarized light is further rotated 45° (+45°) clockwise by the magneto-optical crystal 220, see Figure 2 As shown in s13; further rotated 45° (+45°) clockwise through the wave plate 230, see Figure 2 As shown in s14; finally, the beam is coupled to the second dual-fiber collimator 300 through the second birefringent crystal wedge pair 250; from Figure 2It can be seen that the +45° rotation of the magneto-optical crystal 220 and the +45° rotation of the wave plate 230 are superimposed, so that the polarized light produces a 90° rotation effect; accordingly, the optical paths of the first optical fiber 110 coupled to the fourth optical fiber 320 and the second optical fiber 120 coupled to the third optical fiber 310 are basically the same, and it is only necessary to adjust the coupling angle of the first dual-fiber collimator 100 and the second dual-fiber collimator 300 during debugging;

[0030] The optical path in this example is reversible. When the magnetic element 240 passes a forward current (one direction is defined as the forward direction and the other direction is the reverse direction), a forward magnetic field is generated. At this time, the magneto-optical crystal 220 in the magnetic field of the magnetic element 240 can rotate the polarized light passing through by 45° (+45°) clockwise. The propagation direction from the third optical fiber 310 to the first optical fiber 110 and the fourth optical fiber 320 to the second optical fiber 120 is analyzed and recorded as the reverse propagation direction; the polarization state of the light output from the second dual-fiber collimator 300 is shown in FIG. Figure 2 As shown in s15 in FIG. 1 , the polarized light is transmitted in the reverse direction along the optical path. After passing through the second birefringent crystal wedge plate pair 250, the polarized light is decomposed into polarized light A1, A2 and B1, B2 with perpendicular polarization directions. Figure 2 As shown in s16; the polarized light is further rotated 45° (+45°) clockwise through the wave plate 230, see Figure 2 As shown in s17; the polarized light is further rotated 45° (+45°) clockwise by the magneto-optical crystal 220, see Figure 2 Finally, the beam is combined by the first birefringent crystal wedge pair 210 (see Figure 2 s19) is coupled to the output of the first dual-fiber collimator 100;

[0031] like Figure 3 As shown, when the magnetic element 240 passes a reverse current (one direction is defined as forward and the other direction is defined as reverse), a reverse magnetic field is generated. At this time, the magneto-optical crystal 220 in the magnetic field of the magnetic element 240 can rotate the passing polarized light counterclockwise by 45° (-45°). The propagation direction from the first optical fiber 110 to the third optical fiber 310 and from the second optical fiber 120 to the fourth optical fiber 320 is analyzed and recorded as the forward propagation direction; the input light in the first optical fiber 110 is defined to include polarized light B1 and polarized light B2 whose polarization states are perpendicular to each other, and the input light in the second optical fiber 120 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 s21, the polarized light is transmitted in the forward direction along the optical path. After passing through the first birefringent crystal wedge plate pair 210, the polarized light is decomposed into polarized light A1, A2 and B1, B2 with perpendicular polarization directions. Figure 3 As shown in s22; the polarized light is further rotated 45° (-45°) counterclockwise by the magneto-optical crystal 220, see Figure 2As shown in s23; further rotated 45° (+45°) clockwise through the wave plate 230, see Figure 2 As shown in s24; finally, the beam is coupled to the second dual-fiber collimator 300 through the second birefringent crystal wedge pair 250; from Figure 2 It can be seen that the -45° rotation of the magneto-optical crystal 220 and the +45° rotation of the wave plate 230 cancel each other out, thereby causing the polarized light to produce a non-rotating effect;

[0032] The optical path in this example is reversible. When the magnetic element 240 passes a reverse current (one direction is defined as the forward direction and the other direction is the reverse direction), a reverse magnetic field is generated. At this time, the magneto-optical crystal 220 in the magnetic field of the magnetic element 240 can rotate the polarized light passing through it by 45° (-45°) counterclockwise. The propagation direction from the third optical fiber 310 to the first optical fiber 110 and the fourth optical fiber 320 to the second optical fiber 120 is analyzed and recorded as the reverse propagation direction; the polarization state of the light output from the second dual-fiber collimator 300 is shown in FIG. Figure 3 As shown in s25 in FIG. 1 , the polarized light is transmitted in the reverse direction along the optical path. After passing through the second birefringent crystal wedge plate pair 250, the polarized light is decomposed into polarized light A1, A2 and B1, B2 with perpendicular polarization directions. Figure 3 As shown in s26; the polarized light is further rotated 45° (+45°) clockwise through the wave plate 230, see Figure 3 As shown in s27; the polarized light is further rotated 45° (-45°) counterclockwise by the magneto-optical crystal 220, see Figure 3 Finally, the beam is combined by the first birefringent crystal wedge pair 210 (see Figure 3 s29) is coupled to the output of the first dual-fiber collimator 100;

[0033] In one embodiment, the collimation length of the first dual-fiber collimator 100 matches the collimation length of the second dual-fiber collimator 300 to ensure minimum insertion loss.

[0034] In one embodiment, the first birefringent crystal wedge pair 210, the optical rotation assembly, the wave plate 230, and the second birefringent crystal wedge pair 250 are assembled together using optical adhesive, thereby reducing the volume.

[0035] In one embodiment of the present invention, the first dual-fiber collimator 100 and the second dual-fiber collimator 300 are both polarization-maintaining dual-fiber collimators; Figure 4 As shown, when the magnetic element 240 passes a positive current (one direction is defined as the positive direction and the other direction is the negative direction), a positive magnetic field is generated. At this time, the magneto-optical crystal 220 in the magnetic field of the magnetic element 240 can rotate the polarized light passing through by 45° (+45°) clockwise.

[0036] 110 to the third optical fiber 310, and the second optical fiber 120 to the fourth optical fiber 320, which is recorded as the forward propagation direction; since the first dual-fiber collimator 100 is a polarization-maintaining dual-fiber collimator, it outputs single polarized light, and the output light of the first optical fiber 110 is defined to include polarized light B1 and polarized light B2 with the same polarization state, and the output light of the second optical fiber 120 is defined to include polarized light A1 and polarized light A2 with the same polarization state, wherein the polarization states of the polarized lights B1 and B2 are perpendicular to the polarized lights A1 and A2, see Figure 4 As shown in s31, the polarized light is transmitted in the forward direction along the optical path, and the polarized light is decomposed into polarized light A1, A2 and B1, B2 after passing through the first birefringent crystal wedge plate pair 210. Figure 2 As shown in s32; the polarized light is further rotated 45° (+45°) clockwise by the magneto-optical crystal 220, see Figure 2 As shown in s33; further rotated 45° (+45°) clockwise through the wave plate 230, see Figure 2 As shown in s34; finally, the beam is coupled to the second dual-fiber collimator 300 through the second birefringent crystal wedge pair 250; from Figure 4 It can be seen that the +45° rotation of the magneto-optical crystal 220 and the +45° rotation of the wave plate 230 are superimposed, so that the polarized light produces a 90° rotation effect; accordingly, the optical paths of the first optical fiber 110 coupled to the fourth optical fiber 320 and the second optical fiber 120 coupled to the third optical fiber 310 are basically the same, and it is only necessary to adjust the coupling angle of the first dual-fiber collimator 100 and the second dual-fiber collimator 300 during debugging;

[0037] The optical path in this example is reversible. When the magnetic element 240 passes a forward current (one direction is defined as the forward direction and the other direction is the reverse direction), a forward magnetic field is generated. At this time, the magneto-optical crystal 220 in the magnetic field of the magnetic element 240 can rotate the polarized light passing through by 45° (+45°) clockwise. The propagation direction from the third optical fiber 310 to the first optical fiber 110 and the fourth optical fiber 320 to the second optical fiber 120 is analyzed and recorded as the reverse propagation direction; the polarization state of the light output from the second dual-fiber collimator 300 is shown in FIG. Figure 4 As shown in s35 in FIG. 1 , the polarized light is transmitted in the reverse direction along the optical path. After passing through the second birefringent crystal wedge plate pair 250, the polarized light is decomposed into polarized light A1, A2 and B1, B2. Figure 2 As shown in s36; the polarized light is further rotated 45° (+45°) clockwise through the wave plate 230, see Figure 2 As shown in s37; the polarized light is further rotated 45° (+45°) clockwise by the magneto-optical crystal 220, see Figure 2 Finally, the beam is combined by the first birefringent crystal wedge pair 210 (see Figure 2 s39) is coupled to the output of the first dual-fiber collimator 100;

[0038] like Figure 5 As shown, when a reverse current is passed through the magnetic element 240 (one direction is defined as forward and the other direction is defined as reverse), a reverse magnetic field is generated. At this time, the magneto-optical crystal 220 in the magnetic field of the magnetic element 240 can rotate the passing polarized light counterclockwise by 45° (-45°). The propagation direction from the first optical fiber 110 to the third optical fiber 310 and from the second optical fiber 120 to the fourth optical fiber 320 is analyzed and recorded as the forward propagation direction; since the first dual-fiber collimator 100 is a polarization-maintaining dual-fiber collimator, it outputs single polarized light, and the output light of the first optical fiber 110 is defined to include polarized light B1 and polarized light B2 with the same polarization state, and the output light of the second optical fiber 120 is defined to include polarized light A1 and polarized light A2 with the same polarization state, wherein the polarization states of the polarized lights B1 and B2 are perpendicular to the polarization states of the polarized lights A1 and A2, see Figure 5 As shown in s41, the polarized light is transmitted in the forward direction along the optical path, and the polarized light is decomposed into polarized light A1, A2 and B1, B2 after passing through the first birefringent crystal wedge plate pair 210. Figure 5 As shown in s42; the polarized light is further rotated 45° (-45°) counterclockwise by the magneto-optical crystal 220, see Figure 5 As shown in s43; further rotated 45° (+45°) clockwise through the wave plate 230, see Figure 5 As shown in s44; finally, the beam is coupled to the second dual-fiber collimator 300 through the second birefringent crystal wedge pair 250; from Figure 5 It can be seen that the -45° rotation of the magneto-optical crystal 220 and the +45° rotation of the wave plate 230 cancel each other out, thereby causing the polarized light to produce a non-rotating effect;

[0039] The optical path in this example is reversible. When the magnetic element 240 passes a reverse current (one direction is defined as the forward direction and the other direction is the reverse direction), a reverse magnetic field is generated. At this time, the magneto-optical crystal 220 in the magnetic field of the magnetic element 240 can rotate the polarized light passing through it by 45° (-45°) counterclockwise. The propagation direction from the third optical fiber 310 to the first optical fiber 110 and the fourth optical fiber 320 to the second optical fiber 120 is analyzed and recorded as the reverse propagation direction; the polarization state of the light output from the second dual-fiber collimator 300 is shown in FIG. Figure 5 As shown in s45 in FIG. 1 , the polarized light is transmitted in the reverse direction along the optical path. After passing through the second birefringent crystal wedge plate pair 250, the polarized light is decomposed into polarized light A1, A2 and B1, B2. Figure 5 As shown in s46; the polarized light is further rotated 45° (+45°) clockwise through the wave plate 230, see Figure 5 As shown in s47; the polarized light is further rotated 45° (-45°) counterclockwise by the magneto-optical crystal 220, see Figure 5Finally, the beam is combined by the first birefringent crystal wedge pair 210 (see Figure 5 s49) is coupled to the output of the first dual-fiber collimator 100.

[0040] 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 2x2 magneto-optical switch, characterized in that: The invention comprises a first dual-fiber collimator (100), a first birefringent crystal wedge plate pair (210), an optical rotation component, a wave plate (230), a second birefringent crystal wedge plate pair (250), and a second dual-fiber collimator (300) which are arranged in sequence from left to right; the first dual-fiber collimator (100) comprises a first optical fiber (110) and a second optical fiber (120); the second dual-fiber collimator (300) comprises a third optical fiber (310) and a fourth optical fiber (320); a light beam of the first optical fiber (110) is coupled into the third optical fiber (310), and a light beam of the second optical fiber (120) is coupled into the fourth optical fiber (320), or a light beam of the first optical fiber (110) is coupled into the fourth optical fiber (320), and a light beam of the second optical fiber (120) is coupled into the third optical fiber (310).

2. A 2x2 magneto-optical switch according to claim 1, characterized in that: The first birefringent crystal wedge plate pair (210) and the second birefringent crystal wedge plate pair (250) are Wollaston prisms.

3. A 2x2 magneto-optical switch according to claim 1, characterized in that: The optical rotation component comprises a magneto-optical crystal (220) arranged in a magnetic element (240); the magnetic element (240) generates magnetic fields in positive and negative directions according to the direction of power supply to control the optical rotation direction of the magneto-optical crystal (220) to be positive or negative.

4. A 2x2 magneto-optical switch according to claim 3, characterized in that: The magnetic element (240) is a single coil.

5. The 2x2 magneto-optical switch according to claim 1, characterized in that: The wave plate (230) is a 22.5° wave plate (230).

6. A 2x2 magneto-optical switch according to claim 3, characterized in that: The optical rotation angle of the magneto-optical crystal (220) is 45°.

7. The 2x2 magneto-optical switch according to claim 1, characterized in that: The collimation length of the first dual-fiber collimator (100) matches the collimation length of the second dual-fiber collimator (300), thereby ensuring minimum insertion loss.

8. The 2x2 magneto-optical switch according to claim 1, characterized in that: The first birefringent crystal wedge pair (210), the optical rotation assembly, the wave plate (230), and the second birefringent crystal wedge pair (250) are assembled together using optical adhesive.

9. The 2x2 magneto-optical switch according to claim 1, characterized in that: The first dual-fiber collimator (100) and the second dual-fiber collimator (300) are both polarization-maintaining dual-fiber collimators.

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