Integrated optical fiber isolation device for laser

Abstract

The utility model discloses an integrated optical fiber isolator for a laser in the field of optical devices, which comprises an integrated optical fiber, the integrated optical fiber comprises an optical fiber body and a plurality of micro-nano structure pairs positioned in the optical fiber body, and the optical fiber body comprises a core layer and a cladding. The included angle between the micro-nano structure pair and the forward transmission direction of the integrated optical fiber is smaller than 90 degrees, so that the micro-nano structure pair is coupled with light which is reversely transmitted in the core layer. According to the utility model, the micro-nano structure is processed on the optical fiber body, and the micro-nano structure is utilized to realize the isolation of the reverse light, thereby not only reducing the damage of the reverse light to the device, but also being higher in integration level and smaller in size of the whole isolation device, and reducing the risk of damage.

Description

Technical Field

[0001] This utility model relates to the field of optical devices, specifically to an integrated fiber optic isolation device for lasers. Background Technology

[0002] In fiber laser systems and their applications, fiber lasers, with their significant advantages such as high efficiency, small size, good beam quality, stable and reliable operation, and strong environmental adaptability, have shown extremely important application prospects in many fields such as industrial processing, medicine, and national defense. For narrow-linewidth fiber laser systems, stimulated Brillouin scattering (SBS) becomes the primary factor limiting its power increase. Once the SBS threshold is reached, the forward laser power will stagnate, and all the injected laser energy will be converted into backward Stokes light. This not only seriously affects the system performance but may even cause damage to the system.

[0003] To prevent backlighting from affecting or even damaging high-power fiber laser systems, optical isolators are typically added to the system. Existing optical isolators are mostly large components, requiring the addition of collimating lenses and isolation cores around the optical fibers. For example, patent CN215264116U discloses a dual-fiber in-line isolator and fiber laser, which includes a first dual-fiber collimator, a first isolation module, and a second dual-fiber collimator. This undoubtedly increases the size of the isolator, and its low integration makes it difficult to manufacture and prone to damage.

[0004] The aforementioned shortcomings deserve improvement. Utility Model Content

[0005] To overcome the shortcomings of existing technologies, this invention provides an integrated fiber optic isolator for lasers, which fabricates micro-nano structures on the fiber body to achieve isolation of backlight. This not only reduces the damage to the device caused by backlight, but also makes the entire isolator more integrated and compact, thus reducing the risk of damage.

[0006] The technical solution of this utility model is as follows:

[0007] An integrated fiber optic isolation device for lasers, characterized in that it is composed of integrated optical fibers, the integrated optical fibers comprising:

[0008] The optical fiber body consists of a core and a cladding.

[0009] Several pairs of micro- and nano-structures are located within the optical fiber body, with the angle between the micro- and nano-structure pairs and the forward transmission direction of the integrated optical fiber being less than 90°, so that the micro- and nano-structure pairs are coupled with the reverse-transmitting light in the core layer.

[0010] According to the above-described scheme, the present invention is characterized in that the inner end of the micro / nano structure pair is located within the core layer, and its outer end is located within the cladding layer.

[0011] According to the above-described scheme, the present invention is characterized in that the micro / nano structure is formed by writing along the axial direction of the integrated optical fiber.

[0012] According to the above-described scheme, the present invention is characterized in that the length of the micro-nano structure pair located within the core layer is less than the length of the micro-nano structure pair located within the cladding layer.

[0013] According to the above-described scheme, the present invention is characterized in that the micro-nano structures are uniformly distributed in the circumferential direction of the core layer.

[0014] According to the above-described scheme, the present invention is characterized in that the micro-nano structures are equally spaced along the axial direction of the core layer.

[0015] According to the above-described scheme, the present invention is characterized in that the angles between the micro / nano structure and the forward transmission direction of the integrated optical fiber are all equal.

[0016] According to the above-described scheme, the present invention is characterized in that the depths of the micro-nano structures extending into the core layer are all equal.

[0017] Furthermore, the depth of the micro / nano structure extending into the core layer is no greater than 15% of the diameter of the core layer.

[0018] According to the above-described scheme, the present invention is characterized in that each micro-nano structure pair includes two micro-nano structure units, the two micro-nano structure units having equal lengths, the same distribution angles, and equal angles extending into the core layer.

[0019] The advantages of this utility model based on the above solution are as follows:

[0020] This invention fabricates micro / nano structures on the optical fiber body, utilizing these structures to achieve forward light transmission and reverse light isolation. This allows for the filtering of backward Stokes light or backlight feedback in applications, protecting the stability and reliability of the entire system. Furthermore, this invention eliminates the need for collimators, isolation modules, and other such structures, resulting in a more integrated and compact isolation device that reduces the risk of damage.

[0021] This invention eliminates the need for complex fabrication processes. It utilizes femtosecond laser direct-writing fiber technology to fabricate micro / nano couplers within optical fibers, and the micro / nano structures do not require strict distribution control, thus simplifying the manufacturing process. Furthermore, the fiber optic isolator of this invention, without the application of Ladaic crystals and permanent magnets in its spatial structure, can provide higher power handling capacity, greater stability, and resistance to laser damage. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the isolation section in this utility model;

[0024] Figure 3 This is a side view of the isolation section in this utility model.

[0025] In the diagram, the labels for each item are as follows:

[0026] 01. Integrated optical fiber; 02. Isolation segment; 1. Core layer; 2. Cladding; 3. Micro / nano structure pair; 31. Micro / nano structure single unit. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0028] like Figures 1 to 3 As shown, in order to overcome the shortcomings of existing fiber optic isolation devices for lasers, such as large size, easy damage, and complex installation, this utility model proposes an integrated fiber optic isolation device for lasers. It is made of integrated optical fiber and does not require the application of complex collimators and isolation modules, which can significantly reduce the size of the product and reduce the damage rate. At the same time, this utility model can also fully realize the functions of forward light transmission and reverse light isolation to achieve the purpose of protecting the laser.

[0029] This integrated fiber optic isolator for lasers is directly composed of integrated optical fibers, specifically, such as... Figure 1 As shown, the integrated optical fiber 01 includes an isolation section 02, which is used to achieve reverse light isolation. The forward light is transmitted directly within the integrated optical fiber 01 without loss.

[0030] In this invention, the integrated optical fiber 01 can be provided with one or more isolation segments 02. The spacing between the isolation segments 02 can be set as needed, and the length of the isolation segments 02 can also be set as needed. In the isolation segment 02, the integrated optical fiber 01 includes an optical fiber body and several micro / nano structure pairs 3 located within the optical fiber body. The optical fiber body is used to realize light transmission, and the micro / nano structure pairs 3 are used to realize the isolation of reverse light. This invention directly embeds the micro / nano structure pairs 3 into the integrated optical fiber by writing, eliminating the need for large equipment such as isolators, realizing miniaturized design, and also having higher stability. In addition, the micro / nano structure pairs 3 replace spatial elements such as Faraday crystals and permanent magnets in isolators, and have strong power handling capacity. In this invention, the micro / nano structure pairs 3 avoid coupling loss between the optical fiber and the Faraday crystal and beam collimation loss between optical fibers. At the same time, they can guide the energy in the return light into the cladding and dissipate it in the form of heat, which can avoid thermal damage. This allows the integrated optical fiber to withstand higher power for application in high-power laser systems.

[0031] The optical fiber body includes a core layer 1 and a cladding layer 2. In this embodiment, the integrated optical fiber 01 is a large-core double-clad optical fiber, and its cladding layer 2 includes an inner cladding layer and an outer cladding layer. In this invention, the angle between the micro / nano structure pair 3 and the integrated optical fiber 01 in the forward transmission direction is less than 90°. Therefore, during forward light transmission, it will not couple with the micro / nano structure pair 3 and can transmit normally. During reverse light transmission, coupling occurs upon contact with the micro / nano structure pair 3, and the light is lost through the waveguide of the micro / nano structure pair 3 to the cladding layer 2, thus achieving isolation. It should be noted that... Figure 2 In this design, the direction indicated by the arrow (from left to right) is the forward transmission direction. The aforementioned 90° refers to the angle between the micro / nano structure and the left side of the integrated optical fiber 01 axis being less than 90°. Of course, in order to achieve better forward conduction and ensure effective isolation of reverse light, the angle θ between the micro / nano structure and the forward transmission direction of the integrated optical fiber 01 satisfies the following condition: 30°≤θ≤60°.

[0032] In this invention, each micro-nano structure pair 3 can be regarded as a tree-branch-shaped coupler, which is used to realize forward light conduction and reverse light coupling isolation; combined with water cooling or TEC cooling of the integrated optical fiber segment, the heat at the reverse light isolation position can be rapidly attenuated, avoiding thermal damage and improving power tolerance.

[0033] Figure 2 , Figure 3 This illustrates the principle of how the present invention utilizes micro / nano structures to achieve fiber optic isolation. By configuring micro / nano structures on the 3rd, the present invention can achieve fiber optic isolation without obstructing forward-transmitting light (such as...). Figure 2 In the case shown by the solid arrow pointing to the right, it is possible to control the reverse-transmitted light (such as...). Figure 2(As shown by the dashed arrow pointing to the left) coupling isolation is performed to avoid the influence or even damage of backlight in the laser system. Specifically, when the backlight encounters the micro / nano structure pair 3, the micro / nano structure pair 3 can couple and waveguide the backlight, coupling it to the cladding 2 (such as...). Figure 2 (As shown by the dashed arrows pointing upwards and downwards on both sides) this attenuates the reverse light. The principle of this invention is as follows: When light propagates in the forward direction, the angle between its propagation direction and the micro / nano structure pair 3 is small. The scattering, absorption, or coupling effect of the micro / nano structure pair 3 on the forward-propagating light is very small and can be ignored, thus achieving a "conduction" effect while reducing insertion loss. On the other hand, the angle between the reverse-propagating light and the micro / nano structure pair 3 is large, making it easy to couple with the micro / nano structure pair 3 and be waveguided to the cladding by the micro / nano structure pair 3, thus achieving an "isolation" effect and high isolation. The isolation and waveguide functions of the micro / nano structure pair 3 are its natural properties, and this invention does not limit its specific structure.

[0034] In this invention, each micro / nano structure pair 3 includes two micro / nano structure monomers 31. The two micro / nano structure monomers 31 have equal lengths, the same distribution angles, and the same angles extending into the core layer. The pair arrangement of the micro / nano structure pairs 3 ensures better isolation of reverse light at the position of the micro / nano structure pair 3.

[0035] The micro-nano structure 3 in this invention is formed by writing along the axis of the integrated optical fiber. The femtosecond writing can reduce the processing difficulty of the micro-nano structure 3 and can be completed without special equipment.

[0036] The inner end of the micro / nano structure pair 3 is located within the core layer 1, and its outer end is located within the cladding layer 2. To avoid affecting the forward transmission of light and to better isolate the reverse light, the length of the micro / nano structure pair 3 located within the core layer 1 is shorter than the length of the micro / nano structure pair 3 located within the cladding layer 2. This allows the cladding layer 2 to attenuate more energy during the coupling of the reverse light from the core layer 1 to the cladding layer 2, achieving rapid cooling. Preferably, the depth to which the micro / nano structure pair 3 extends into the core layer 1 is no greater than 15% of the diameter of the core layer 1, thereby reducing the precision requirements for writing the micro / nano structure pair 3 while simultaneously meeting the requirements of forward conduction and reverse isolation required by this invention.

[0037] In one specific embodiment, the micro / nano structures 3 are uniformly distributed circumferentially in the core layer 1.

[0038] In one specific embodiment, the micro / nano structures are evenly spaced 3 along the axial direction of the core layer 1.

[0039] In one specific embodiment, the angles between the micro / nano structure pair 3 and the forward transmission direction of the integrated optical fiber 01 are all equal.

[0040] In one specific embodiment, the micro / nano structures 3 extend into the core layer 1 to the same depth.

[0041] In other embodiments, the micro-nano structure pairs 3 do not need to be uniformly distributed around the core layer 1, nor do they need to be equally spaced along the axial direction of the core layer 1. The tilt angles of the micro-nano structure pairs 3 also do not need to be consistent, and their depths into the core layer 1 can also be unequal, thereby reducing the difficulty of femtosecond writing of the micro-nano structure pairs 3.

[0042] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0043] The present utility model patent has been described above with reference to the accompanying drawings. Obviously, the implementation of the present utility model patent is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present utility model patent, or the direct application of the inventive concept and technical solution of the present utility model patent to other occasions without modification, are all within the protection scope of the present utility model.

Claims

1. An integrated fiber optic isolation device for lasers, characterized in that, Composed of integrated optical fibers, the integrated optical fibers include: The optical fiber body consists of a core and a cladding. Several pairs of micro- and nano-structures are located within the optical fiber body, with the angle between the micro- and nano-structure pairs and the forward transmission direction of the integrated optical fiber being less than 90°, so that the micro- and nano-structure pairs are coupled with the reverse-transmitting light in the core layer.

2. The integrated fiber optic isolator for lasers according to claim 1, characterized in that, The inner end of the micro / nano structure pair is located within the core layer, and its outer end is located within the cladding layer.

3. The integrated fiber optic isolator for lasers according to claim 1, characterized in that, The micro / nano structure is formed by writing along the axial direction of the integrated optical fiber.

4. The integrated fiber optic isolator for lasers according to claim 1, characterized in that, The length of the micro-nano structure pair located within the core layer is less than the length of the micro-nano structure pair located within the cladding layer.

5. The integrated fiber optic isolator for lasers according to claim 1, characterized in that, The micro / nano structures are uniformly distributed circumferentially in the core layer.

6. The integrated fiber optic isolator for lasers according to claim 1, characterized in that, The micro-nano structures are evenly spaced along the axial direction of the core layer.

7. The integrated fiber optic isolator for lasers according to claim 1, characterized in that, The angles between the micro / nano structure and the forward transmission direction of the integrated optical fiber are all equal.

8. The integrated fiber optic isolator for lasers according to claim 1, characterized in that, The micro / nano structures all have the same depth extending into the core layer.

9. The integrated fiber optic isolator for a laser according to claim 8, characterized in that, The depth to which the micro / nano structure extends into the core layer is no greater than 15% of the diameter of the core layer.

10. The integrated fiber optic isolator for a laser according to any one of claims 1-9, characterized in that, Each of the micro-nano structure pairs includes two micro-nano structure monomers, which have the same length, the same distribution angle, and the same angle of insertion into the core layer.

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