A high-isolation optical isolator
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FUJIAN HITRONICS TECH INC
- Filing Date
- 2025-09-15
- Publication Date
- 2026-08-07
AI Technical Summary
[0002]光隔离器是激光加工系统中的关键器件，用于防止反向传输的光对光源造成干扰或破坏；随着高功率激光器的发展，传统光隔离器在高功率条件下容易出现热效应和损伤，导致隔离度下降甚至器件损坏
[0013]相较于现有技术，本实用新型的有益效果是：通过在光路中加入补偿波片，可以对反向传输激光的旋转角进行补偿，使其严格为0度，解决了由于环境因素和内部热效应带来的隔离度波动的问题，提升了隔离器的隔离度；同时在隔离器内部放置了第一偏振分束器，进一步滤除了从第二光分束器透过来的s偏振光，进一步提高了隔离度。
Smart Images
Figure CN224609362U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of laser technology, and in particular to a high-isolation optical isolator. Background Technology
[0002] Optical isolators are key components in laser processing systems, used to prevent back-transmitted light from interfering with or damaging the light source. With the development of high-power lasers, traditional optical isolators are prone to thermal effects and damage under high-power conditions, leading to a decrease in isolation or even device failure.
[0003] Currently, research on high-power optical isolators mainly focuses on improving isolation and enhancing thermal stability. Existing high-power optical isolators typically employ a series connection of two-stage isolators to improve isolation, but this method increases system complexity, resulting in a complex structure and high manufacturing costs. Furthermore, the rotation angle of the Faraday rotator is easily affected by the environment, leading to fluctuations in isolation, and significant thermal effects under high-power conditions, which can cause device performance degradation. Another approach is to use PBS as a beam splitter to improve isolation, but the extinction ratio of the PBS polarization beam splitter is only about 20dB, meaning that some of the strong reflected light will still return to the laser. Utility Model Content
[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of this utility model is to provide a high-isolation optical isolator, which is beneficial to solving the problem of isolation fluctuation caused by environmental factors and internal thermal effects, and is beneficial to improving the isolation of the isolator.
[0005] The technical solution adopted in this utility model is as follows:
[0006] The high-isolation optical isolator of this utility model is characterized by comprising, in sequence, an input fiber collimator, a first optical beam splitter, a compensating waveplate, a rotating plate, a Faraday rotator, a first polarization beam splitter, and a second optical beam splitter. The Faraday rotator is composed of a magneto-optical crystal and magnets located on both sides of the magneto-optical crystal. The magnets are used to provide a magnetic field for the magneto-optical crystal.
[0007] The input fiber collimator is used to input laser light; the first and second optical beam splitters are used to split a beam of light into p-polarized light and s-polarized light, or to combine p-polarized light and s-polarized light into a single beam; the rotator is used to rotate the polarization direction of the laser by 45 degrees; the Faraday rotator is used to perform a 45-degree non-reciprocal rotation of the polarization direction of the laser; the compensation waveplate is used to compensate for the polarization direction rotation angle of the reverse-transmitted laser to be strictly 0 degrees; the first polarization beam splitter is used to transmit p-polarized light in the transmitted laser and filter out s-polarized light.
[0008] Preferably, a second polarization beam splitter is provided between the first optical beam splitter and the compensation waveplate.
[0009] Preferably, the material of the above-mentioned magneto-optical crystal is TGG, TSAG or bismuth iron garnet.
[0010] Preferably, the compensation angle of the aforementioned compensation waveplate is adjustable.
[0011] Preferably, the optical axis direction of the compensation waveplate is substantially consistent with the optical axis direction of the rotating plate, and the included angle between the two is adjustable, with an adjustable range of -5° to 5°.
[0012] Preferably, the aforementioned compensation waveplate and the rotating plate are half-waveplates.
[0013] Compared with the prior art, the beneficial effects of this utility model are: by adding a compensation waveplate in the optical path, the rotation angle of the reverse-transmitting laser can be compensated to make it strictly 0 degrees, which solves the problem of isolation fluctuation caused by environmental factors and internal thermal effects and improves the isolation of the isolator; at the same time, a first polarization beam splitter is placed inside the isolator to further filter out the s-polarized light transmitted from the second optical beam splitter, which further improves the isolation. Attached Figure Description
[0014] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a schematic diagram of the forward light transmission structure of Embodiment 1 of this utility model. Figure 2 This is a schematic diagram of the reverse light transmission structure of Embodiment 1 of this utility model.
[0015] Figure 3 This is a schematic diagram of the forward light transmission structure of Embodiment 2 of this utility model. Figure 4 This is a schematic diagram of the reverse light transmission structure in Embodiment 2 of this utility model. Detailed Implementation
[0016] Example 1, as Figure 1 As shown, the high-isolation optical isolator of this utility model includes an input fiber collimator 1, a first optical beam splitter 2, a compensation waveplate 3, a rotating plate 4, a Faraday rotator 5, a first polarization beam splitter 6, and a second optical beam splitter 7 arranged in sequence. The Faraday rotator 5 is composed of a magneto-optical crystal 9 and a magnet 8.
[0017] The Faraday rotator 5 consists of a magneto-optical crystal 9 and magnets 8 located on both sides of the magneto-optical crystal 9. The magnets 8 are used to provide a magnetic field for the magneto-optical crystal 9. The input fiber collimator 1 is used to input laser light. The first optical beam splitter 2 and the second optical beam splitter 7 are used to split a beam of light into p-polarized light and s-polarized light, or to combine p-polarized light and s-polarized light into a single beam of light. The rotating plate 4 is used to rotate the polarization direction of the laser by 45 degrees. The Faraday rotator 5 is used to perform a 45-degree non-reciprocal rotation of the polarization direction of the laser. The compensation waveplate 3 is used to compensate for the polarization direction rotation angle of the reverse-transmitted laser to be strictly 0 degrees. The first polarization beam splitter 6 is used to transmit p-polarized light in the transmitted laser and filter out s-polarized light.
[0018] In this embodiment, the compensation waveplate 3 and the rotating plate 4 are half-waveplates. The optical axis direction of the compensation waveplate 3 is roughly the same as that of the rotating plate 4. The angle between the two is adjustable, with an adjustable range of -5° to 5°. In this embodiment, the preferred angle is 2°. The material of the magneto-optical crystal 4 is TGG.
[0019] like Figure 1 The optical path shown in the diagram, where the collimated laser emitted from fiber collimator 1 is input, is split into p-polarized light and s-polarized light after passing through the first optical beam splitter 2:
[0020] For p-polarized light, it passes directly through and is incident on the compensating waveplate 3, where its polarization direction is rotated 2° clockwise. Then it is incident on the rotating plate 4, where it is rotated another 45° clockwise, for a total rotation of 47°. Then it is incident on the Faraday rotator 5, where its polarization direction is rotated another 45° clockwise, for a total rotation of 92°. This means that most of the incident p-polarized light becomes s-polarized light. However, it also contains a small portion of p-polarized light. The s-polarized light is reflected and output by the second beam splitter 7, while the remaining p-polarized light is transmitted through the second beam splitter 7 and leaks out as ineffective light.
[0021] For s-polarized light, it is reflected by the first beam splitter 2 and incident on the compensating waveplate 3, where its polarization direction is rotated 2° clockwise. Then it is incident on the rotating plate 4, where it is rotated another 45° clockwise, for a total rotation of 47°. Then it is incident on the Faraday rotator 5, where its polarization direction is rotated another 45° clockwise, for a total rotation of 92°. This means that most of the incident s-polarized light becomes p-polarized light, but it still contains a small portion of s-polarized light. The p-polarized light is then transmitted by the first polarization beam splitter 6, while the contained s-polarized light is reflected by the first polarization beam splitter 6 and leaks out as ineffective light. The p-polarized light that passes through the first polarization beam splitter 6 is transmitted by the second beam splitter 7 and output. Finally, the reflected s-polarized light and the transmitted p-polarized light are combined into a single laser beam output.
[0022] Reverse light path, such as Figure 2 As shown, the externally input return light is split into p-polarized light and s-polarized light by the second optical beam splitter 7:
[0023] For p-polarized light, it passes directly through the second beam splitter 7. Due to the insufficient extinction ratio of the second beam splitter 7, the p-polarized light still contains a small portion of s-polarized light. Then, the reflected light is incident on the first polarization beam splitter 6, where the s-polarized light is reflected and cannot return to the collimator 1. The p-polarized light continues to pass through the first polarization beam splitter 6 and is then input into the Faraday rotator 5. Theoretically, its polarization direction is rotated counterclockwise by 45°. However, due to external factors and internal thermal effects, the rotation angle is not strictly 45°. Here, we assume a deviation of 2°, i.e., a rotation of 47°. Then, it is incident on the rotating plate 4, where its polarization direction is rotated clockwise by 45°. That is, the p-polarized light is rotated a total of 2 degrees counterclockwise. Then, it is incident on the compensating waveplate 2, where its polarization direction is rotated clockwise by 2 degrees. That is, the polarization direction of the p-polarized light does not rotate in the end and is then transmitted through the first beam splitter 2, thus preventing it from returning to the collimator 1 and achieving isolation of the p-polarized light.
[0024] For the s-polarized light, it is reflected by the second optical beam splitter 7 and then incident on the Faraday rotator 5. Theoretically, its polarization direction is rotated counterclockwise by 45°. However, due to the influence of external factors and internal thermal effects, the rotation angle is not strictly 45°. Here, we assume that it has a deviation of 2°, that is, it is rotated by 47°. Then it is incident on the rotating plate 4, and its polarization direction will be rotated clockwise by 45°. That is, the s-polarized light is rotated counterclockwise by a total of 2 degrees. Then it is incident on the compensating waveplate 2, and its polarization direction is rotated clockwise by 2 degrees. That is, the polarization direction of the s-polarized light does not rotate in the end. Finally, it is incident on the first optical beam splitter 2, reflected by the first optical beam splitter 2, and passes through its side, so that it cannot return to the input fiber collimator, thus achieving the isolation of the s-polarized light.
[0025] Example 2, as Figure 3 and Figure 4 As shown, the difference between Embodiment 2 and Embodiment 1 is that: firstly, a second polarization beamsplitter 10 is placed between the first optical beamsplitter 2 and the compensation waveplate 3; secondly, for example... Figure 3 The p-polarized light in the forward optical path shown, after passing through the first beam splitter 2, directly passes through the second polarization beam splitter 10 and then enters the compensating waveplate 3; thirdly, for such... Figure 4 The s-polarized light after passing through the compensation waveplate 3 in the reverse optical path shown is first reflected to the outside of the isolator by the second polarization beam splitter 10, and then the remaining s-polarized light is incident on the first optical beam splitter 2.
[0026] Apart from the differences mentioned above, the rest of Embodiment 2 is the same as Embodiment 1, and will not be repeated here.
[0027] The beneficial effects of this invention are as follows: by adding a compensation waveplate to the optical path, the rotation angle of the reverse-transmitting laser can be compensated to be strictly 0 degrees, which solves the problem of isolation fluctuation caused by environmental factors and internal thermal effects and improves the isolation of the isolator; at the same time, a first polarization beam splitter is placed inside the isolator to further filter out the s-polarized light transmitted from the second optical beam splitter, which further improves the isolation.
Claims
1. A high-isolation optical isolator, characterized in that: The system includes an input fiber collimator (1), a first optical beam splitter (2), a compensating waveplate (3), a rotator (4), a Faraday rotator (5), a first polarization beam splitter (6), and a second optical beam splitter (7) arranged in sequence. The Faraday rotator (5) is composed of a magneto-optical crystal (9) and magnets (8) located on both sides of the magneto-optical crystal (9). The magnets (8) are used to provide a magnetic field for the magneto-optical crystal (9). The input fiber collimator (1) is used to input laser light; the first optical beam splitter (2) and the second optical beam splitter (7) are used to split a beam of light into p-polarized light and s-polarized light, or to combine p-polarized light and s-polarized light into a beam of light; the rotating plate (4) is used to rotate the polarization direction of the laser by 45 degrees; the Faraday rotator (5) is used to rotate the polarization direction of the laser by 45 degrees non-reciprocally; the compensation waveplate (3) is used to compensate for the polarization direction rotation angle of the reverse-transmitted laser to be strictly 0 degrees; the first polarization beam splitter (6) is used to transmit p-polarized light in the transmitted laser and filter out s-polarized light.
2. The high-isolation optical isolator according to claim 1, characterized in that: A second polarization beam splitter (10) is provided between the first optical beam splitter (2) and the compensation waveplate (3).
3. The high-isolation optical isolator according to claim 1, characterized in that: The magneto-optical crystal is made of TGG, TSAG, or bismuth iron garnet.
4. The high-isolation optical isolator according to claim 1, characterized in that: The compensation angle of the compensation waveplate is adjustable.
5. The high-isolation optical isolator according to claim 1, characterized in that: The optical axis of the compensation waveplate (3) is roughly the same as that of the rotating plate (4), and the angle between them is adjustable, with an adjustable range of -5° to 5°.
6. The high-isolation optical isolator according to claim 1, characterized in that: The compensation waveplate (3) and the rotating plate (4) are half-waveplates.