Optical isolator with high dynamic isolation degree

Abstract

The utility model relates to the technical field of optical isolators, in particular to an optical isolator with high dynamic isolation. Comprising polarization splitting prisms which are divided into a first polarization splitting prism and a second polarization splitting prism, and the first polarization splitting prism and the second polarization splitting prism are arranged along a first direction; the collimator is arranged on one side, far away from the second polarization splitting prism, of the first polarization splitting prism, and the collimator emits light beams; and the optical rotation sheet is divided into a first optical rotation sheet and a second optical rotation sheet which are located between the first polarization splitting prism and the second polarization splitting prism, and the first optical rotation sheet and the second optical rotation sheet are arranged along the second direction. And when the light beam is reversely propagated between the first limit position and the second limit position, the P polarized light beam passes through the second optical rotation sheet, reaches the upper half part of the first polarization splitting prism and cannot enter the collimator to be coupled into the optical fiber, and the S polarized light beam passes through the first polarization splitting prism and then is emitted in the direction perpendicular to the light beam direction.

Description

Technical Field

[0001] The utility model relates to the technical field of optical isolators, in particular to an optical isolator with high dynamic isolation. Background Art

[0002] An optical isolator is a passive optical device that allows only one-way light to pass through. Its working principle is based on the non-reciprocity of Faraday rotation. The return light of the optical fiber can be well isolated by the optical isolator.

[0003] Optical isolators mainly use the Faraday effect of magneto-optical crystals. The characteristics of optical isolators are: low forward insertion loss, high reverse isolation, and high return loss. The direction of light is restricted so that light can only be transmitted in one direction, thereby improving the efficiency of light wave transmission.

[0004] Existing optical isolators are equipped with optical rotation devices and polarization splitters. However, the echo return light of the optical fiber does not necessarily return along the original path, but may return at a certain angle, causing the light path after passing through the optical rotation device and the polarization splitter to be offset, and will return to the laser to a certain extent, which will cause damage to the laser. Utility Model Content

[0005] Therefore, the utility model aims to overcome the technical problems in the prior art, thereby providing an optical isolator with high dynamic isolation.

[0006] The utility model provides an optical isolator with high dynamic isolation, comprising:

[0007] A polarization beam splitter prism, divided into a first polarization beam splitter prism and a second polarization beam splitter prism, wherein the first polarization beam splitter prism and the second polarization beam splitter prism are arranged along a first direction;

[0008] A collimator is arranged on a side of the first polarization beam splitter prism away from the second polarization beam splitter prism, and the collimator emits a light beam;

[0009] A polarizer, divided into a first polarizer and a second polarizer, located between the first polarizer and the second polarizer, wherein the first polarizer and the second polarizer are arranged along the second direction;

[0010] A magneto-optical rotation component is arranged between the optical rotation plate and the second polarization beam splitter prism;

[0011] Wherein, when the light beam passes through the polarization beam splitter prism, it is divided into a P-polarized light beam and an S-polarized light beam, the polarization directions of the P-polarized light beam and the S-polarized light beam are perpendicular, and there is a gap between the first optical rotator and the second optical rotator, and the gap is filled with thermal conductive silicone;

[0012] The collimator is located at the end side of the first polarization beam splitter prism, so that when the light beam returns at the first extreme position, the P polarized light beam irradiates the thermal conductive silicone, and when the light beam returns at the second extreme position, the S polarized light beam irradiates the thermal conductive silicone.

[0013] Furthermore, the magneto-optical rotation component comprises:

[0014] A magneto-optical rotator crystal is arranged between the optical rotator plate and the second polarization beam splitter prism;

[0015] Furthermore, the magneto-optical rotation component also includes:

[0016] There are two magnets, which are distributed at two ends of the magneto-optical rotatory crystal in the second direction;

[0017] When the light beam enters the magneto-optical rotator crystal from the optical rotator plate, the deflection direction of the light beam in the optical rotator plate and the magneto-optical rotator crystal is the same.

[0018] Furthermore, the gap between the first optical rotator and the second optical rotator satisfies the following formula:

[0019] 0<L<D–Φ,

[0020] Wherein, L is the gap between the first optical rotator and the second optical rotator, D is the distance between the P polarized light beam and the S polarized light beam, and Φ is the diameter of the light beam.

[0021] Furthermore, it also includes:

[0022] The aperture is arranged on a side of the second polarization beam splitter prism away from the magneto-optical rotation crystal, and a light-transmitting portion is arranged in the middle of the aperture.

[0023] Furthermore, it also includes:

[0024] The double concave collimator is arranged on a side of the aperture away from the second polarization beam splitter prism.

[0025] Furthermore, it also includes:

[0026] The plano-convex collimator is arranged on a side of the biconcave collimator away from the aperture.

[0027] Furthermore, the convex surface of the plano-convex collimator is located on a side of the plano-convex collimator away from the bi-concave collimator.

[0028] The technical solution of this utility model has the following advantages:

[0029] The utility model provides an optical isolator with high dynamic isolation. A light beam is emitted through a collimator. When the light beam propagates in the forward direction, it is divided into a P polarized light beam and an S polarized light beam in a first polarization beam splitter prism. The P polarized light beam passes through a first optical rotator, and the S polarized light beam passes through a second optical rotator. The P polarized light beam and the S polarized light beam are deflected 45° clockwise or counterclockwise in the optical rotator. After the P polarized light beam and the S polarized light beam enter a magneto-optical rotation component, they are deflected again by 45° in the same direction. At this time, the P polarized light beam and the S polarized light beam are respectively deflected by 90°, and the polarization states of the two are interchanged. When passing through the second polarization beam splitter prism, the beams are combined and emitted from the second polarization beam splitter prism.

[0030] When the light beam propagates in the reverse direction at the first extreme position, the light beam is divided into a P-polarized light beam and an S-polarized light beam in the second polarization beam splitter prism, wherein the P-polarized light beam and the S-polarized light beam are deflected 45° clockwise or counterclockwise in the magneto-optical rotation component, the P-polarized light beam is irradiated on the thermal conductive silica gel, the S-polarized light beam is deflected 45° in the reverse direction in the first optical rotation plate, and the deflection of the S-polarized light beam is 0°, and the S-polarized light beam is emitted perpendicular to the light beam direction after passing through the first polarization beam splitter prism.

[0031] When the light beam propagates in the reverse direction at the second extreme position, the light beam is divided into a P-polarized light beam and an S-polarized light beam in the second polarization beam splitter prism, wherein the P-polarized light beam and the S-polarized light beam are deflected 45° clockwise or counterclockwise in the magneto-optical rotation component, the P-polarized light beam is located in the upper half of the magneto-optical rotation component and the first polarization beam splitter prism and does not enter the collimator, and the S-polarized light beam is irradiated on the thermal conductive silicone. The thermal conductive silicone can absorb the light beam and conduct the heat away.

[0032] When the light beam propagates in the opposite direction between the first extreme position and the second extreme position, the P-polarized light beam passes through the second optical rotator and reaches the second optical rotator and the upper half of the magneto-optical rotator crystal, and cannot enter the collimator to be coupled into the optical fiber. The S-polarized light beam passes through the first polarization beam splitter and is emitted perpendicular to the light beam direction.

[0033] Therefore, in the present application, even if the light beam returns at a certain angle, it will not return to the laser and cause damage to the laser.

[0034] The utility model provides an optical isolator with high dynamic isolation. The magnet can apply a magnetic field to the location of a magneto-optical rotation crystal, so that a light beam is deflected when passing through the magneto-optical rotation crystal.

[0035] The utility model provides an optical isolator with high dynamic isolation, wherein the gap between a first optical rotator and a second optical rotator satisfies 0<L<D–Φ, and the co-optical area of ​​a light beam can be reduced.

[0036] The utility model provides an optical isolator with high dynamic isolation. The double concave collimator and the plano-convex collimator can expand and collimate the light beam to form a collimated and expanded output light spot. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 This is a schematic diagram of forward propagation of the conventional optical isolator of the utility model;

[0039] Figure 2 It is a reverse propagation schematic diagram of the existing optical isolator of the utility model;

[0040] Figure 3 This is a schematic diagram of the first extreme position structure of reverse propagation of the utility model;

[0041] Figure 4 This is a schematic diagram of the second extreme position structure of the reverse propagation of the utility model;

[0042] Figure 5 It is a schematic diagram of the positions of the P polarized light beam and the S polarized light beam during forward propagation of the utility model;

[0043] Figure 6 This is a schematic diagram of forward propagation without gaps in the utility model;

[0044] Figure 7 This is a schematic diagram of reverse propagation without gaps in the utility model;

[0045] Figure 8 This is a schematic diagram of forward propagation when the utility model is in the first limit position without a gap.

[0046] Description of reference numerals;

[0047] 1. First polarization beam splitter prism; 2. Second polarization beam splitter prism; 3. Collimator; 4. First optical rotator; 5. Second optical rotator; 6. P-polarized light beam; 7. S-polarized light beam; 8. Magneto-optical rotator crystal; 9. Magnet; 10. Aperture; 11. Double concave collimator; 12. Plano-convex collimator. DETAILED DESCRIPTION

[0048] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0049] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it 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.

[0051] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] Example

[0053] The basic components of the optical isolator are two birefringent crystals, an optical rotator, a magneto-optical rotator crystal and an external magnetic field. The optical axes of the two birefringent crystals form an angle of 45°. Figure 1 As shown. A beam of forward linear polarized light is divided into o light and e light after passing through the first birefringent crystal and transmitted separately. After passing through the optical rotator, the two beams rotate 45° clockwise at the same time (observed in the direction of forward light propagation, the same below), and then rotate 45° clockwise again under the action of the magneto-optical rotator crystal and the external magnetic field. At this time, the two beams rotate 90° respectively, and their polarization states are interchanged. The o light becomes the e light, and the e light becomes the o light. After passing through the second birefringent crystal, they are combined and emitted.

[0054] Its reverse isolation optical path is as follows Figure 2As shown. After a beam of reverse linear polarized light passes through the first birefringent crystal, it is divided into o light and e light and transmitted separately. Under the action of the magneto-optical rotator crystal and the external magnetic field, it rotates 45° counterclockwise (observed in the direction of forward light propagation). Then, after passing through the optical rotator, the two beams of light are simultaneously rotated 45° clockwise. At this time, the two beams of light are rotated 0° respectively, and their polarization states have not changed. The o light is still the o light, and the e light is still the e light. After passing through the second birefringent crystal, they cannot be combined and emitted, and deviation occurs, achieving the effect of isolating the reverse light.

[0055] like Figures 3 to 5 A specific implementation of an optical isolator with high dynamic isolation is shown, where dynamic isolation refers to the ability of the optical isolator to block return light from all directions. The optical isolator with high dynamic isolation includes:

[0056] A polarization beam splitter prism, divided into a first polarization beam splitter prism 1 and a second polarization beam splitter prism 2, wherein the first polarization beam splitter prism 1 and the second polarization beam splitter prism 2 are arranged along a first direction;

[0057] A collimator 3 is arranged on a side of the first polarization beam splitter prism 1 away from the second polarization beam splitter prism 2, and the collimator 3 emits a light beam;

[0058] A polarizer, divided into a first polarizer 4 and a second polarizer 5, located between the first polarizer prism 1 and the second polarizer prism 2, wherein the first polarizer 4 and the second polarizer 5 are arranged along the second direction;

[0059] The magneto-optical rotation component is arranged between the optical rotation plate and the second polarization beam splitter prism 2;

[0060] Wherein, when the light beam passes through the polarization beam splitter prism, it is divided into a P-polarized light beam 6 and an S-polarized light beam 7, the polarization directions of the P-polarized light beam 6 and the S-polarized light beam 7 are perpendicular, and there is a gap between the first optical rotator 4 and the second optical rotator 5, and the gap is filled with thermal conductive silicone;

[0061] The collimator 3 is located at the end side of the first polarization beam splitter prism 1, so that when the light beam returns at the first extreme position, the P polarized light beam 6 irradiates the thermal conductive silicone, and when the light beam returns at the second extreme position, the S polarized light beam 7 irradiates the thermal conductive silicone. Figure 3 As shown, the light beam returns from the positive extreme position of the second direction, and the second extreme position is as shown in the attached Figure 4 As shown, the light beam returns from the negative extreme position of the second direction.

[0062] A light beam is emitted through the collimator. When the light beam propagates in the forward direction, after the light beam passes through the collimator 3, it is divided into a P-polarized light beam 6 and an S-polarized light beam 7 in the first polarization beam splitter prism 1, wherein the P-polarized light beam 6 passes through the first optical rotator 4, and the S-polarized light beam 7 passes through the second optical rotator 5. The P-polarized light beam 6 and the S-polarized light beam 7 are deflected 45° clockwise or counterclockwise in the optical rotator. When the P-polarized light beam 6 and the S-polarized light beam 7 enter the magneto-optical rotation component, they are deflected again by 45° in the same direction. At this time, the P-polarized light beam 6 and the S-polarized light beam 7 are deflected by 90° respectively, and the polarization states of the two are interchanged. When passing through the second polarization beam splitter prism 2, they are combined and emitted from the second polarization beam splitter prism 2.

[0063] When the light beam propagates in the reverse direction at the first extreme position, the light beam is divided into a P-polarized light beam 6 and an S-polarized light beam 7 in the second polarization beam splitter prism 2, wherein the P-polarized light beam 6 and the S-polarized light beam 7 are deflected 45° clockwise or counterclockwise in the magneto-optical rotation component, the P-polarized light beam 6 is irradiated on the thermal conductive silica gel, the S-polarized light beam 7 is reversely deflected 45° in the first optical rotation plate 4, and the deflection of the S-polarized light beam 7 is 0°, and the S-polarized light beam 7 is emitted perpendicular to the light beam direction after passing through the first polarization beam splitter prism 1.

[0064] When the light beam propagates in the reverse direction at the second extreme position, the light beam is divided into a P-polarized light beam 6 and an S-polarized light beam 7 in the second polarization beam splitter prism 2, wherein the P-polarized light beam 6 and the S-polarized light beam 7 are deflected 45° clockwise or counterclockwise in the magneto-optical rotation component, the P-polarized light beam 6 is located in the upper half of the magneto-optical rotation component and the second optical rotation plate 5 (the second direction is positive upward) and does not enter the collimator, and the S-polarized light beam 7 is irradiated on the thermal conductive silica gel. The thermal conductive silica gel can absorb the light beam and conduct the heat away.

[0065] When the light beam propagates in the reverse direction between the first extreme position and the second extreme position, the P-polarized light beam 6 passes through the second rotator 5 and reaches the upper half of the first polarization beam splitter prism 1. The collimator 3 is located at the negative end of the first polarization beam splitter prism 1 in the second direction and cannot enter the collimator 3 to be coupled into the optical fiber. The S-polarized light beam 7 passes through the first polarization beam splitter prism 1 and is emitted perpendicular to the direction of the light beam.

[0066] Therefore, in the present application, even if the light beam returns at a certain angle, it will not return to the laser and cause damage to the laser.

[0067] Furthermore, the magneto-optical rotation component comprises:

[0068] A magneto-optical rotator crystal 8 is arranged between the optical rotator and the second polarization beam splitter prism 2;

[0069] Furthermore, the magneto-optical rotation component also includes:

[0070] Two magnets 9 are distributed at two ends of the magneto-optical rotation crystal 8 in the second direction;

[0071] When the light beam enters the magneto-optical rotatory crystal 8 from the optical rotator, the deflection direction of the light beam in the optical rotator and the magneto-optical rotatory crystal 8 is the same.

[0072] The magnet 9 can apply a magnetic field to the location of the magneto-optical rotator crystal 8 , so that the light beam is deflected when passing through the magneto-optical rotator crystal 8 .

[0073] Further, such as Figure 5 As shown, the gap between the first optical rotator 4 and the second optical rotator 5 satisfies the following formula:

[0074] 0<L<D–Φ,

[0075] Wherein, L is the gap between the first optical rotator 4 and the second optical rotator 5, D is the distance between the P polarized light beam 6 and the S polarized light beam 7, and Φ is the diameter of the light beam. The isotropic area of ​​the light beam can be reduced.

[0076] Furthermore, it also includes:

[0077] The aperture 10 is arranged on the side of the second polarization beam splitter prism 2 away from the magneto-optical rotation crystal 8, and a light-transmitting portion is arranged in the middle of the aperture 10. The light beam passes through the light-transmitting portion of the aperture 10 when propagating in the forward or reverse direction.

[0078] Furthermore, it also includes:

[0079] The biconcave collimator 11 is arranged on a side of the aperture 10 away from the second polarization beam splitter prism 2 .

[0080] Furthermore, it also includes:

[0081] The plano-convex collimator 12 is arranged on a side of the bi-concave collimator 11 away from the aperture 10 .

[0082] Furthermore, the convex surface of the plano-convex collimator 12 is located on a side of the plano-convex collimator 12 away from the bi-concave collimator 11 .

[0083] The double concave collimator 11 and the plano-convex collimator 12 can expand and collimate the light beam to form a collimated and expanded output light spot.

[0084] If there is no gap between the first optical rotator and the second optical rotator, or the two are integrated, the forward transmission light path is as follows: Figure 6As shown. The light emitted from the collimator is divided into P light and S light for transmission through the polarization beam splitter prism. The S light is transmitted, and the P light is returned. Under the action of the optical rotator, they are simultaneously rotated 45° clockwise. Then, under the action of the external magnetic field and the magneto-optical rotator, they are simultaneously rotated 45° clockwise. At this time, the two beams of light are rotated 90° respectively, and their polarization states are interchanged. They are combined and emitted through the polarization beam splitter prism. Then, they are collimated and collimated by the double concave collimator and the plano-convex collimator to form a collimated and enlarged output light spot.

[0085] Its reverse isolation optical path is as follows Figure 7 As shown. The reverse light is converged into a small light spot under the action of the plano-convex collimator and the biconcave collimator, and is divided into P light and S light for transmission through the polarization beam splitter prism. The S light is transmitted, and the P light returns. Under the action of the external magnetic field and the magneto-rotator, it rotates 45° counterclockwise at the same time, and then rotates 45° clockwise at the same time under the action of the rotator. At this time, the two beams of light are rotated by 0° respectively, and their polarization states do not change. Finally, they can no longer be coupled back to collimation through the polarization beam splitter prism, thereby achieving the effect of isolating the reverse light.

[0086] However, if the reverse light (i.e., the return light) is incident at an angle, a portion of its energy will directly act on the collimator when passing through the isolator, such as Figure 8 As shown, it then returns to the optical fiber through the collimator, causing damage to the optical components inside the laser.

[0087] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. An optical isolator with high dynamic isolation, characterized in that: include: A polarization beam splitter prism, divided into a first polarization beam splitter prism (1) and a second polarization beam splitter prism (2), wherein the first polarization beam splitter prism (1) and the second polarization beam splitter prism (2) are arranged along a first direction; A collimator (3) is arranged on a side of the first polarization beam splitter (1) away from the second polarization beam splitter (2), and the collimator (3) emits a light beam; A polarizer, divided into a first polarizer (4) and a second polarizer (5), located between the first polarizer (1) and the second polarizer (2), wherein the first polarizer (4) and the second polarizer (5) are arranged along the second direction; A magneto-optical rotation component is arranged between the optical rotation plate and the second polarization beam splitter prism (2); Wherein, when the light beam passes through the polarization beam splitter prism, it is split into a P-polarized light beam (6) and an S-polarized light beam (7), the polarization directions of the P-polarized light beam (6) and the S-polarized light beam (7) are perpendicular, and there is a gap between the first optical rotator (4) and the second optical rotator (5), and the gap is filled with thermal conductive silica gel; The collimator (3) is located at the end side of the first polarization beam splitter (1), so that when the light beam returns at the first extreme position, the P polarized light beam (6) irradiates the thermal conductive silicone, and when the light beam returns at the second extreme position, the S polarized light beam (7) irradiates the thermal conductive silicone.

2. The optical isolator with high dynamic isolation according to claim 1, characterized in that: The magneto-optical rotation component comprises: The magneto-optical rotation crystal (8) is arranged between the optical rotation plate and the second polarization beam splitting prism (2).

3. The optical isolator with high dynamic isolation according to claim 2, characterized in that: The magneto-optical rotation component also includes: Two magnets (9) are distributed at two ends of the magneto-optical rotation crystal (8) in the second direction; When the light beam enters the magneto-optical rotation crystal (8) from the optical rotation plate, the light beam has the same deflection direction in the optical rotation plate and the magneto-optical rotation crystal (8).

4. The optical isolator with high dynamic isolation according to claim 1, characterized in that: The gap between the first optical rotator (4) and the second optical rotator (5) satisfies the following formula: 0<L<D–Φ, Wherein, L is the gap between the first optical rotator (4) and the second optical rotator (5), D is the distance between the P polarized light beam (6) and the S polarized light beam (7), and Φ is the diameter of the light beam.

5. The optical isolator with high dynamic isolation according to claim 2, characterized in that: Also includes: The aperture (10) is arranged on a side of the second polarization beam splitting prism (2) away from the magneto-optical rotation crystal (8), and a light-transmitting portion is arranged in the middle of the aperture (10).

6. The optical isolator with high dynamic isolation according to claim 5, characterized in that: Also includes: A double concave collimator (11) is arranged on a side of the aperture (10) away from the second polarization beam splitting prism (2).

7. The optical isolator with high dynamic isolation according to claim 6, characterized in that: Also includes: A plano-convex collimator (12) is arranged on a side of the biconcave collimator (11) away from the aperture (10).

8. The optical isolator with high dynamic isolation according to claim 7, characterized in that: The convex surface of the plano-convex collimator (12) is located on a side of the plano-convex collimator (12) away from the biconcave collimator (11).

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