Preparation method of fluorotellurite glass optical fiber combiner

Abstract

The invention discloses a preparation method of a fluorotellurite glass optical fiber combiner, which comprises the following steps: sequentially inserting three fluorotellurite glass input optical fibers into a fluorotellurite glass sleeve to form a fluorotellurite glass optical fiber bundle; placing the combined optical fiber bundle on a clamp of an optical fiber fusion splicer, and tapering the optical fiber bundle by using a tapering function of the optical fiber fusion splicer after the optical fiber bundle is stably clamped; vertically cutting in the waist region of the tapering optical fiber bundle by using a ceramic blade, so that the tapering optical fiber bundle is partially broken in the waist region; and a cutting machine is used for cutting a section of fluorotellurite glass output optical fiber, and the output optical fiber and the cut tapering optical fiber bundle are subjected to breakpoint fusion welding at the waist area. The invention provides a novel 3 * 1 optical fiber beam combiner made of fluorotellurite glass optical fibers, and the beam combiner has the characteristics of high damage threshold and high transmission efficiency in near-infrared and middle-infrared bands, and particularly has important significance in improving the output power of a middle-infrared band laser.

Description

Technical Field

[0001] The present invention relates to the field of all-fiber lasers, and in particular to a method for preparing a fluorotellurite glass optical fiber combiner. Background Art

[0002] The rapid development of high-power fiber lasers has benefited from the progress of semiconductor laser manufacturing technology, fiber theory and fiber manufacturing technology, and many new fiber structure technology solutions have also been greatly developed. At the same time, the structure of fiber lasers has gradually transitioned from spatial optical paths to all-fiber optical paths. Due to the poor stability of spatial optical paths, susceptibility to environmental influences, and difficulties in thermal management, early high-power fiber lasers were difficult to be widely used in defense, industry and other fields. The all-fiber structure high-power fiber laser has the advantages of small size, good heat dissipation performance and stable structure. The all-fiber structure fiber laser integrates the pump source, resonant cavity and gain medium through a fiber combiner, fiber grating and gain fiber. Among them, the fiber combiner increases the laser output power of a single fiber by combining multiple laser light sources into one optical fiber.

[0003] The mid-infrared band (2-5 μm) contains several important optical transmission windows in the atmosphere, making the light sources in this band have important applications in atmospheric remote sensing, laser guidance, mid-infrared optoelectronic countermeasures, atmospheric communications, infrared imaging, infrared ranging and other fields. However, the output power of laser light sources related to the mid-infrared band is relatively low, and there is an urgent need to increase the output power of the light source to increase the application range of mid-infrared lasers. Mid-infrared fiber combiners can convert free-space lasers into fiber lasers, and can combine multiple laser light sources to increase the output power. At present, soft glass optical fibers are required for laser transmission in the mid-infrared band, but soft glass optical fibers are difficult to make into fiber combiners due to their low thermal conductivity, easy deliquesce and low mechanical strength.

[0004] Therefore, technicians in this field are committed to developing a method for preparing a fluorotellurite glass optical fiber combiner to overcome the problems existing in the prior art. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is how to increase the output power of the mid-infrared band laser.

[0006] To achieve the above object, the present invention provides a method for preparing a fluorotellurite glass optical fiber combiner, comprising the following steps: Step 1, inserting three fluorotellurite glass input optical fibers into a fluorotellurite glass sleeve in sequence to form a fluorotellurite glass optical fiber bundle; Step 2: Place the assembled optical fiber bundle on the fixture of the optical fiber fusion splicer. After the fixture is stabilized, use the taper function of the optical fiber fusion splicer to taper the optical fiber bundle to form a left taper area, a waist area, and a right taper area. Step 3: Use a ceramic blade to vertically cut the waist region of the tapered optical fiber bundle, so that the tapered optical fiber bundle is partially disconnected in the waist region; Step 4: Use a cutting machine to cut a section of fluorotellurite glass output optical fiber, and use a fiber fusion splicer to fusion-splice the output optical fiber with the cut tapered optical fiber bundle at the waist breakpoint.

[0007] Furthermore, the core diameter of the fluorotellurite glass input optical fiber in step 1 is 15 μm, and the cladding diameter is 250 μm.

[0008] Furthermore, the inner diameter of the fluorotellurite glass sheath in step 1 is 540 μm, and the outer diameter is 1000 μm.

[0009] Furthermore, the parameter settings of the fiber fusion splicer in step 2 are: fiber bundle diameter 1000μm, waist diameter 330μm, left taper length 5mm, waist length 5mm, right taper length 11mm, taper shape is linear, and taper power is 25~35bit.

[0010] Furthermore, in the step 2, the waist-area taper power of the optical fiber fusion splicer is kept consistent with the taper power of the cone-area taper.

[0011] Furthermore, the preheating time of the optical fiber fusion splicer in step 2 is set to 5 to 15 seconds.

[0012] Furthermore, the optical fiber fusion splicer in step 2 uses an automatic feeding setting so that the left clamp moves at a constant speed, and the right clamp automatically adjusts the feeding speed according to the feedback program, and the left constant speed is set to 0.2 mm / s.

[0013] Furthermore, the cutting degree of the waist region in step 3 is less than 1°.

[0014] Furthermore, the core diameter of the fluorotellurite glass output optical fiber in step 4 is 135 μm, the cladding diameter is 250 μm, and the optical fiber length is 2 cm.

[0015] Furthermore, the welding parameters of the carbon dioxide welding machine in step 4 are: setting the welding heating area to the center of the welding point, setting the overlap distance during welding to 0 μm, the main melting power to 100 bits, and the main melting time to 400 ms.

[0016] The beneficial effects of the present invention are: The present invention provides a novel 3×1 optical fiber combiner made of fluorotellurite glass optical fiber. The combiner has the characteristics of high damage threshold and high transmission efficiency in near-infrared and mid-infrared bands, and is particularly important for improving the output power of mid-infrared band lasers.

[0017] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a manufacturing flow chart of a 3×1 optical fiber combiner according to a preferred embodiment of the present invention; Figure 2 is a cross-sectional view of a fluorotellurate glass optical fiber used in a preferred embodiment of the present invention; Figure 3 is a cross-sectional view of a fluorotellurite glass sleeve used in a preferred embodiment of the present invention; Figure 4 is a cross-sectional structural arrangement diagram of a beam combiner of a preferred embodiment of the present invention; Figure 5 This is a physical picture of a preferred embodiment of the present invention after the tapered optical fiber bundle and the output optical fiber are fused; Figure 6 This is a physical picture of a beam combiner according to a preferred embodiment of the present invention.

[0019] Among them, 1-input optical fiber, 2-casing, 3-optical fiber bundle, 4-ceramic blade, 5-output optical fiber, 31-left cone area, 32-waist area, 33-right cone area. DETAILED DESCRIPTION

[0020] The following describes the preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0021] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings.

[0022] Since fluorotellurate glass optical fiber has good transmittance, excellent thermal stability and high laser damage threshold in the mid-infrared band and the near-infrared band, the present invention manufactures a fluorotellurate glass optical fiber combiner using fluorotellurate glass as a matrix.

[0023] like Figure 1 As shown, the present invention provides a method for preparing a fluorotellurite glass optical fiber combiner, comprising the following steps: Step S1, manually inserting the fluorotellurate glass input optical fiber 1 cleaned with alcohol into the fluorotellurate glass sleeve 2, and inserting three input optical fibers 1 in sequence to form a fluorotellurate glass optical fiber bundle 3.

[0024] Step S2, placing the assembled optical fiber bundle 3 on the clamp of the fusion splicer, and after being stably clamped, using the taper function of the fusion splicer to taper the optical fiber bundle 3 to form a left taper region 31, a waist region 32 and a right taper region 33.

[0025] Step S3: Use the ceramic blade 4 to vertically cut the waist region 32 of the tapered optical fiber bundle 3. Since the clamp has some pulling force, the tapered optical fiber bundle 3 will be partially disconnected in the waist region 32.

[0026] Step S4: Use a cutting machine to cut a section of the fluorotellurite glass output optical fiber 5, and fuse it with the cut tapered optical fiber bundle 3 at the breakpoint in the waist region 32. Example

[0027] This embodiment provides a method for preparing a fluorotellurite glass optical fiber combiner, comprising the following steps: Step 1. Use dust-free paper soaked in anhydrous alcohol to carefully wipe three bare fluorotellurate glass optical fibers (without coating) of similar length. The core cladding diameters of the fluorotellurate glass optical fibers are 15 / 250μm respectively. The optical fibers are input optical fibers, and the cross-section of the optical fibers is as follows: Figure 2 As shown in the figure, due to the fragile nature of fluorotellurate glass optical fiber, be careful when wiping.

[0028] Step 2: Manually insert the alcohol-cleaned input optical fibers into a fluorotellurite glass sleeve with an inner diameter of 540 μm and an outer diameter of 1000 μm (cross section as shown in Figure 2). Figure 3 As shown in the figure), the three input optical fibers are arranged in a triangle under the constraint of the sleeve, as shown in the figure. Figure 4 Similarly, wipe the outer surface of the sleeve with a lint-free paper moistened with anhydrous alcohol.

[0029] Step 3. Set the taper program on the fiber fusion splicer (Fujikura LZM-125). The parameters of each part are as follows: fiber bundle diameter 1000μm, waist diameter 330μm (due to the characteristics of soft glass, the actual waist diameter after taper is 250μm), left taper length 5mm, waist length 5mm, right taper length 11mm, taper shape is linear, taper power is 25~35bit (it can heat the fiber to 450~550℃). Due to different power standards of different types of splicers, it is only necessary to adjust the taper power to a power slightly higher than the power that can melt the taper fiber. The waist taper power is consistent with the taper power of the taper area. The preheating time is 5~15s. Adjust the preheating time to the optimal parameter according to the taper effect at the beginning of the taper stage. The function of rotating while taper is not used when tapering. Use the Auto-Feeding setting to make the left fixture move at a constant speed, and the right fixture automatically adjusts the feeding speed according to the feedback program. The left fixed speed is set to 0.2mm / s. The taper speed can be increased or decreased as appropriate according to the specific taper situation. After setting the parameters, click the Initialize button, and the completed taper program will be sent to the welding machine, and the displacement platform in the welding machine will move to the taper preparation position.

[0030] Step 4: Place two fusion splicer clamps with a clamping size of 1000 μm in the clamp slots of the displacement platform, place the tapered fiber bundle in the clamps and clamp it, so that the clamps on both sides clamp the sleeve part, and the laser heating position is the part of the fiber bundle bound by the sleeve.

[0031] Step 5. Start the taper program, wait for the taper to be completed, and use the measurement function to check the difference between the actual taper curve and the set taper curve. Due to the characteristics of soft glass optical fiber, the waist diameter of the actual taper curve will be smaller than the set value, but it is only necessary to ensure that the taper part of the actual taper curve is linear and the actual waist diameter meets the requirements.

[0032] Step 6. Open the shielding cover of the fusion splicer. Without opening the clamp, use a ceramic blade to gently cut a vertical cut on the waist area of ​​the tapered fiber bundle. The tension between the clamps will automatically break the waist area at the cutting point.

[0033] Step 7, repeat the above steps (step 1 to step 6) until a sample with a cutting degree (the degree refers to the angle between the vertical axis of the waist breakpoint surface and the axial direction of the optical fiber core) less than 1° is cut out from the breakpoint of the tapered optical fiber waist region.

[0034] Step 8: Use a fiber cutter to cut a section of fluorotellurate glass optical fiber with a core and cladding diameter of 135 / 250 μm, which is used as the output fiber of the combiner. The length of the section of optical fiber is 2 cm.

[0035] Step 9. Use a fusion splicer to fuse the tapered fiber bundle with the output fiber. The main fusion parameters of the fiber fusion splicer (Fujikura LZM-125) are: set the fusion heating area to the center of the fusion point, set the overlap distance to 0μm during fusion, the main fusion power to 100bit, and the main fusion time to 400ms. Because different fusion splicers use different heating sources, the main fusion power and main fusion time settings can be adjusted according to specific circumstances. It is only necessary to ensure that the tapered fiber bundle and the output fiber are fused in a relatively short time (several hundred milliseconds). Use the set fusion program to fuse the cut tapered fiber bundle and the output fiber. The actual picture after fusion is as follows: Figure 5 The overall structure of the beam combiner is shown in Figure 6 shown.

[0036] The present invention provides a preparation method for a 3×1 optical fiber combiner based on fluorotellurite glass optical fiber and fluorotellurite glass sleeve, and the combiner has the advantages of high transmission efficiency and high power bearing in the mid-infrared and near-infrared bands. The combiner uses a fluorotellurite glass sleeve with an outer diameter of 1000 μm and an inner diameter of 540 μm to bundle three fluorotellurite glass input optical fibers with core cladding diameters of 15 / 250 μm, and then uses a carbon dioxide fusion splicer to taper the right taper region to a taper optical fiber bundle with a length of 11 mm and a taper ratio of 4. The taper optical fiber bundle is cut at the waist region and fused with an output optical fiber with a core cladding diameter of 135 / 250 μm, respectively, to form a 3×1 optical fiber combiner. The combiner has been tested and found to have no crosstalk between each input optical fiber, and no crosstalk effect on laser beam combining in different bands. The applicable wavelength band of the beam combiner is 2 to 3.5 μm. At a wavelength of 2 μm, the overall transmission efficiency of the beam combiner is 83%, and when the output laser is 8 W, there is no obvious temperature increase of the beam combiner.

[0037] The present invention provides a novel 3×1 optical fiber combiner made of fluorotellurite glass optical fiber. The combiner has the characteristics of high damage threshold and high transmission efficiency in near-infrared and mid-infrared bands, and is particularly important for improving the output power of mid-infrared band lasers.

[0038] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a fluorotellurite glass optical fiber combiner, characterized in that: The following steps are involved: Step 1, inserting three fluorotellurite glass input optical fibers into a fluorotellurite glass sleeve in sequence to form a fluorotellurite glass optical fiber bundle; Step 2: Place the assembled optical fiber bundle on the fixture of the optical fiber fusion splicer. After the fixture is stabilized, use the taper function of the optical fiber fusion splicer to taper the optical fiber bundle to form a left taper area, a waist area, and a right taper area. Step 3: Use a ceramic blade to vertically cut the waist region of the tapered optical fiber bundle, so that the tapered optical fiber bundle is partially disconnected in the waist region; Step 4: Use a cutting machine to cut a section of fluorotellurite glass output optical fiber, and use a fiber fusion splicer to fusion-splice the output optical fiber with the cut tapered optical fiber bundle at the waist breakpoint.

2. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 1, wherein: The core diameter of the fluorotellurite glass input optical fiber in step 1 is 15 μm, and the cladding diameter is 250 μm.

3. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 2, characterized in that: The inner diameter of the fluorotellurite glass sleeve in step 1 is 540 μm, and the outer diameter is 1000 μm.

4. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 3, characterized in that: The parameter settings of the fiber fusion splicer in step 2 are: fiber bundle diameter 1000μm, waist diameter 330μm, left taper length 5mm, waist length 5mm, right taper length 11mm, taper shape is linear, and taper power is 25-35bit.

5. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 4, characterized in that: In the step 2, the waist-area taper power of the optical fiber fusion splicer is consistent with the taper power of the cone-area taper.

6. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 3, characterized in that: The preheating time of the optical fiber fusion splicer in step 2 is set to 5 to 15 seconds.

7. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 3, characterized in that: The optical fiber fusion splicer in step 2 uses automatic feeding setting, so that the left clamp moves at a constant speed, and the right clamp automatically adjusts the feeding speed according to the feedback program, and the left constant speed is set to 0.2 mm / s.

8. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 1, wherein: The cutting degree of the waist region in step 3 is less than 1°.

9. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 1, wherein: The core diameter of the fluorotellurite glass output optical fiber in step 4 is 135 μm, the cladding diameter is 250 μm, and the optical fiber length is 2 cm.

10. The method for preparing a fluorotellurite glass optical fiber combiner according to claim 9, characterized in that: The fusion parameters of the optical fiber fusion splicer in step 4 are: setting the fusion heating area to the center of the fusion point, setting the overlap distance to 0 μm during fusion, the main fusion power to 100 bits, and the main fusion time to 400 ms.

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