Optical fiber to free space isolator

Abstract

The utility model discloses an optical fiber to free space isolator, which relates to the field of optical fiber isolators and comprises an isolator shell, one end of the isolator shell is connected with an optical fiber, and the other end of the isolator shell is connected with an optical fiber. A first polarization beam splitting element, a polarized light rotating device, a Faraday rotator and a second polarization beam splitting element are sequentially installed on the inner wall of the isolator shell along the optical channel path. The optical fiber to free space isolator accurately regulates and controls the light polarization direction by means of the quartz rotating plate and the Faraday rotator, realizes one-way transmission, improves the light isolation performance, reduces the reverse light interference, and guarantees the stability and accuracy of optical signals. And the beam expanding collimating lens group and the divergence angle adjusting cover can flexibly adjust the light characteristics, so that the universality is enhanced.

Description

Technical Field

[0001] This utility model relates to the field of fiber optic isolators, and more particularly to fiber optic to free space isolators. Background Technology

[0002] With the rapid development of fields such as optical communication, laser processing, and optical measurement, increasingly higher demands are being placed on the precise control and processing of optical signals. In these applications, it is often necessary to convert optical signals in optical fibers into free space for further operations and transmission, while ensuring the quality and stability of the optical signals and avoiding negative impacts on system performance from interference factors such as reflected light.

[0003] Traditional optical transmission systems face numerous challenges in the transition between optical fiber and free space. For instance, the polarization state of light is difficult to control effectively and is easily affected by external environmental factors (such as temperature and stress), leading to reduced transmission efficiency and increased bit error rate. Furthermore, in some complex optical systems, the lack of efficient optical isolation means allows reflected light to re-enter the light source or other optical components, causing system instability or even damage. Utility Model Content

[0004] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a fiber-to-free-space isolator that improves the quality and reliability of optical signals during the conversion process, thereby meeting the high performance and high stability requirements of modern optical systems.

[0005] To address the problems in the existing technology, the technical solution of this utility model is as follows:

[0006] An optical fiber to free space isolator includes an isolator housing, one end of which is connected to an optical fiber. Along the optical path, a first polarization beam splitter, a polarization rotation device, a Faraday rotator, and a second polarization beam splitter are sequentially installed on the inner wall of the isolator housing.

[0007] The isolator housing is provided with a beam expanding and collimating lens group at the emission end, and a divergence angle adjustment cover is also provided in the middle of the beam expanding and collimating lens group.

[0008] Light is split into P-polarized light and S-polarized light by the first polarization beam splitter in the optical channel. The polarization direction of the light is rotated by the polarization rotator. The polarization direction of the light is rotated again at the Faraday rotator. The P-polarized light and S-polarized light are combined and output by the second polarization beam splitter.

[0009] Preferably, both the first polarization beam splitter and the second polarization beam splitter are PBS lenses.

[0010] Preferably, the polarizing rotator is a quartz rotator.

[0011] Preferably, the Faraday rotator consists of a TGG crystal and two magnetic poles that are centrally symmetrically distributed around the outer periphery of the TGG crystal, with the two magnetic poles located on opposite sides of the optical channel and the TGG crystal located on the optical channel.

[0012] Preferably, both P-polarized light and S-polarized light are rotated by 45 degrees at the polarization rotator and the Faraday rotator.

[0013] Compared with the prior art, the advantages of this utility model are as follows:

[0014] 1. This utility model, by sequentially arranging a first polarization beam splitter (PBS lens), a polarization rotation device (quartz rotation plate), a Faraday rotator, and a second polarization beam splitter (PBS lens) within the optical channel, can precisely control and adjust the polarization state of light, ensuring that the polarization state is effectively managed during the conversion of light from optical fiber to free space, improving the transmission quality and stability of optical signals, and reducing signal loss caused by polarization state disorder.

[0015] 2. The Faraday rotator provided by this utility model consists of a TGG crystal and two magnetic poles that are centrally symmetrically distributed on its outer periphery. It utilizes the Faraday effect to cause a non-reciprocal rotation of the polarization direction of light, which can effectively block the transmission of reverse light. This characteristic is crucial for protecting the light source and other optical components from interference from reflected light, greatly improving the stability and reliability of the entire optical system, and reducing the noise and bit error rate caused by reflected light. This makes the isolator of this invention have significant advantages in fields with high requirements for optical isolation, such as optical communication and laser processing.

[0016] 3. This utility model, through the beam expanding and collimating lens group set at the output end of the isolator housing and the divergence angle adjustment cover in the middle, can flexibly adjust the parameters of the output beam. The beam expanding and collimating lens group can enlarge the diameter of the beam and collimate it to meet different application requirements, such as improving the transmission efficiency and stability of the beam in long-distance optical transmission; while the divergence angle adjustment cover can finely adjust the divergence angle of the beam according to the actual situation, further optimizing the propagation characteristics of the beam and making it better adaptable to various complex optical systems and working environments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0018] Figure 2 This is a top view of the present invention.

[0019] Reference numerals: 1. Isolator housing; 100. Optical channel; 2. Optical fiber; 3. First polarization beam splitter; 4. Quartz rotating plate; 5. TGG crystal; 6. Magnetic pole; 7. Second polarization beam splitter; 8. Beam expanding and collimating lens group; 9. Divergence angle adjustment cover. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0021] Please see Figure 1 and Figure 2 This embodiment provides an optical fiber 2 to free space isolator, including an isolator housing 1, with an optical fiber 2 connected to one end of the isolator housing 1. The inner wall of the isolator housing 1 has an optical channel 100 that runs through the center of the isolator housing 1. Along the path of the optical channel 100, a first polarization beam splitter 3, a quartz rotating plate 4, a TGG crystal 5, two magnetic poles 6 arranged symmetrically around the TGG crystal 5, and a second polarization beam splitter 7 are sequentially installed on the inner wall of the isolator housing 1. The first polarization beam splitter 3 and the second polarization beam splitter 7 are both PBS lenses. The two magnetic poles 6 are located on both sides of the optical channel 100. The TGG crystal 5 is located on the optical channel 100. The position of the magnetic poles 6 does not obstruct the passage of light.

[0022] The exit end of the isolator housing 1 is provided with a beam expanding and collimating lens group 8, and a divergence angle adjustment cover 9 is also provided in the middle of the beam expanding and collimating lens group 8.

[0023] When light enters the isolator from the optical fiber 2 connected to one end of the isolator housing 1, the light propagates along the optical channel 100 in the middle of the inner wall of the isolator housing 1. First, the light encounters the first polarization beam splitter 3 (PBS lens). According to the principle of polarization beam splitting, the light is decomposed into P-polarized light and S-polarized light. These two types of polarized light continue to advance along their respective paths within the optical channel 100.

[0024] Next, the P-polarized light and the S-polarized light reach the quartz rotating plate 4, which can rotate the polarization direction of the polarized light passing through it by 45 degrees, thereby changing the polarization state distribution of the light.

[0025] After passing through the quartz rotating plate 4, the polarized light continues its journey into the Faraday rotator region, which consists of a TGG crystal and two magnetic poles 6. In this region, due to the interaction between the magnetic field (generated by the two magnetic poles 6) and the TGG crystal, the polarization direction of the light is further rotated by 45 degrees. These two 45-degree rotations ensure that the polarization direction of the light meets the requirements for subsequent beam combining, and also provide optical isolation to prevent interference from the propagation of backlight.

[0026] Finally, the P-polarized light and S-polarized light, after being processed by the Faraday rotator, reach the second polarization beam splitter 7 (also a PBS lens). Here, due to the previous adjustment of the polarization direction, the two polarized beams can be combined and output from the output end of the isolator housing 1.

[0027] In summary, this invention, through the synergistic effect of the quartz rotating plate 4 and the Faraday rotator, precisely controls the polarization direction of light, effectively achieving unidirectional light transmission, greatly improving optical isolation performance, reducing backlight interference, and ensuring the stability and accuracy of optical signal transmission. Secondly, the inclusion of the beam-expanding collimating lens group 8 and the divergence angle adjustment cover 9 allows for flexible adjustment of the output light characteristics, making it better adaptable to different optical systems and enhancing the versatility and practicality of the isolator. Furthermore, its compact structural design integrates multiple functional components within a limited space, facilitating installation and use, reducing production costs and equipment complexity, and promoting large-scale application.

[0028] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fiber-to-free space isolator, comprising an isolator housing (1), characterized in that, One end of the isolator housing (1) is connected to an optical fiber (2), and the inner wall of the isolator housing (1) is sequentially installed along the optical channel (100) path with a first polarization beam splitter (3), a polarization rotation device, a Faraday rotator and a second polarization beam splitter (7). The isolator housing (1) is provided with a beam expanding collimating lens group (8) at the exit end, and a divergence angle adjustment cover (9) is also provided in the middle of the beam expanding collimating lens group (8). The light is split into P-polarized light and S-polarized light by the first polarization beam splitter (3) in the optical channel (100). The polarization direction of the light is rotated by the polarization beam rotator. The polarization direction of the light continues to be rotated at the Faraday rotator. The P-polarized light and S-polarized light are combined and output at the second polarization beam splitter (7).

2. The fiber-to-free-space isolator according to claim 1, characterized in that, Both the first polarization beam splitter (3) and the second polarization beam splitter (7) are PBS lenses.

3. The fiber-to-free-space isolator according to claim 2, characterized in that, The polarizing rotator is a quartz rotating plate (4).

4. The fiber-to-free-space isolator according to claim 3, characterized in that, The Faraday rotator consists of a TGG crystal (5) and two magnetic poles (6) that are centrally symmetrically distributed on the outer periphery of the TGG crystal (5). The two magnetic poles (6) are located on both sides of the optical channel (100), and the TGG crystal (5) is located on the optical channel (100).

5. The fiber-to-free-space isolator according to claim 4, characterized in that, Both P-polarized and S-polarized light are rotated by 45 degrees at the polarization rotator and the Faraday rotator.

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