A high-power optical fiber combiner

Abstract

The present invention relates to a high-power optical fiber combiner, comprising a cone region (3) formed by combining, melting, tapering, and cutting N input optical fibers (1), the cone region (3) being fused with an output optical fiber (2), a low-refractive-index glue region (5) being formed on the surface of the cone region (3), and a first high-refractive-index glue region (4) and a second high-refractive-index glue region (6) being formed in the upstream and downstream regions of the cone region (3). The high-refractive-index glue regions (4) and (6) can respectively filter out the cladding transmission light in the input optical fiber (1) and the output optical fiber (2), thereby improving the beam quality. The low-refractive-index glue region (5) enables the cladding transmission light in the cone region (3) to still satisfy the law of total reflection at the cladding-low-refractive-index glue region interface, thereby reducing the optical power loss. In addition, the cone region and the fusion joint can be well protected by the above three glue regions, thereby playing a mechanical protection role for the device.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, and in particular to a high-power optical fiber combiner. Background Art

[0002] Fiber lasers offer numerous advantages, including high beam quality, compact structure, small size, light weight, easy heat dissipation, and excellent operational stability. They are widely used in numerous fields, including industry, medicine, and national defense. Fiber combiners are key components of fiber lasers and can be categorized by their function: pump combiners and power combiners. The power of a single pump source is limited. Pump combiners simultaneously inject multiple pump sources into a single fiber, thereby increasing the pump power. Power combiners, on the other hand, simultaneously inject multiple medium-power single-mode lasers into a single multimode fiber to achieve high-power laser output.

[0003] The primary manufacturing process for a fiber combiner includes combining the input fibers, fusing and tapering the combined fibers, cutting the fused-tapered fiber bundle, splicing it with the output fibers, and packaging. The fused region of the optical fiber undergoes coating stripping, and tapering the fused region into a tapered area necessitates protection. Furthermore, the optical path in this region is complex, easily leading to reduced beam quality and optical power loss. Existing processes simply mechanically protect this region with glue, resulting in a certain decrease in the device's optical performance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-power optical fiber combiner in view of the above-mentioned prior art, which can both mechanically protect the cone area and prevent the degradation of optical performance.

[0005] The technical solution adopted by the present invention to solve the above-mentioned problem is: a high-power optical fiber combiner, including a tapered area formed by bundling, melting, tapering and cutting N input optical fibers, the tapered area is fused with an output optical fiber, a low-refractive-index glue area is formed on the surface of the tapered area, and a first high-refractive-index glue area and a second high-refractive-index glue area are respectively formed in the upstream and downstream areas of the tapered area.

[0006] Preferably, the parameters of the input optical fiber and the output optical fiber satisfy the brightness conservation criterion: Among them D in , NA in are the core diameter and numerical aperture of the input optical fiber, D out , NA out are the core diameter and numerical aperture of the output optical fiber, respectively.

[0007] Preferably, the length L of the tapered region satisfies the adiabatic tapering criterion.

[0008] Preferably, the first high refractive index glue area and the second high refractive index glue area are made of the same glue, and the refractive index n H ≥1.55; the low refractive index glue area uses the glue with a refractive index n L ≤1.42.

[0009] Preferably, the range of the low refractive index glue area exceeds the range of the tapered area, and the first high refractive index glue area and the second high refractive index glue area respectively cover the areas near the critical points where the coatings of the input optical fiber and the output optical fiber are stripped.

[0010] Compared with the prior art, the advantages of the present invention are:

[0011] The present invention sets a high-refractive-index glue zone with a refractive index greater than that of the cladding near the critical area where the coating of N input optical fibers is stripped, so that the cladding transmission light does not satisfy the law of total reflection at the cladding-high-refractive-index glue zone interface, so that the cladding transmission light is filtered out from the high-refractive-index glue zone after entering the coating stripping area, and the core transmission light is not affected, which can improve the beam quality; after the core transmission light of the N input optical fibers enters the cone area, the core transmission optical fiber will be transferred to the cladding due to the reduction in optical fiber size, and the cone area has no coating layer. By setting the refractive index glue zone, the core transmission optical fiber will be transferred to the cladding due to the reduction in optical fiber size, and the cone area has no coating layer. A low-refractive-index glue zone with a refractive index lower than that of the cladding is used to ensure that the cladding-transmitted light still satisfies the law of total internal reflection at the cladding-low-refractive-index glue zone interface, thus reducing optical power loss. After the light in the cone zone enters the output fiber, a small portion of the fiber will be transmitted in the cladding. A high-refractive-index glue zone with a refractive index higher than that of the cladding is then set up again to ensure that the cladding-transmitted light does not satisfy the law of total internal reflection at the cladding-high-refractive-index glue zone interface. As a result, the cladding-transmitted light will also be filtered out from the high-refractive-index glue zone, while the core-transmitted light will not be affected. This can improve the beam quality of the output light. In addition, the above three glue zones can well protect the cone zone and the fusion splice, providing mechanical protection for the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a method for gluing an optical fiber combiner according to the present invention.

[0013] Figure 2 This is an energy distribution diagram of the output light of a certain branch of a fiber combiner of the present invention.

[0014] in:

[0015] Input optical fiber 1, output optical fiber 2, tapered region 3, first high refractive index glue region 4, low refractive index glue region 5, second high refractive index glue region 6. DETAILED DESCRIPTION

[0016] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0017] This embodiment provides a high-power fiber combiner, including an input fiber 1 and an output fiber 2. The parameters of the input fiber 1 and the output fiber 2 satisfy the brightness conservation criterion: Among them D in , NA in are the diameter and numerical aperture of input fiber 1, D out , NA out are the diameter and numerical aperture of the output optical fiber 2, respectively. N input optical fibers 1 are bundled, fused, tapered, and cleaved to form a tapered region 3. The length L of the tapered region 3 meets the adiabatic tapering criterion. The tapered region 3 is fused to the output optical fiber 2 and coated with a low-refractive-index adhesive region 5. A first high-refractive-index adhesive region 4 and a second high-refractive-index adhesive region 6 are coated upstream and downstream of the tapered region, respectively.

[0018] Example:

[0019] See also Figure 1 , is a (7+1)×1 power combiner, the parameters of the 7 input optical fibers 1 are: core / clad diameter is 20 / 130μm, NA is 0.08; the parameters of the output optical fibers 2 are: core / clad diameter is 100 / 120μm, NA is 0.22. The high refractive index glue areas 4 and 6 use the same glue, whose refractive index is 1.565, and the low refractive index glue area 5 uses glue with a refractive index of 1.41. The power combiner made by the glue binding method of the present invention is injected with a wavelength of 1080nm, a power of 500W, and a beam quality of M into its 7 input optical fibers respectively. 2 For a signal laser with a power of 1.2, the branch signal efficiency of the power combiner is between 96.4% and 97.2%, and the beam quality of the branch output light is M 2 The average value is 6.85. Figure 2 This is the energy distribution diagram of the output light from one of the branches. It can be seen that the output light is close to Gaussian distribution.

[0020] In addition to the above embodiments, the present invention also includes other implementation methods. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of protection of the claims of the present invention.

Claims

1. A high-power fiber combiner, comprising a tapered region (3) formed by combining, fusing, tapering, and cutting N input optical fibers (1), wherein the tapered region (3) is fused to an output optical fiber (2), and characterized in that: A low-refractive-index glue area (5) is formed on the surface of the tapered area (3), and a first high-refractive-index glue area (4) and a second high-refractive-index glue area (6) are respectively formed in the upstream and downstream regions of the tapered area (3); the parameters of the input optical fiber (1) and the output optical fiber (2) satisfy the brightness conservation criterion: Among them D in , NA in are the core diameter and numerical aperture of the input optical fiber (1), D out , NA out are respectively the core diameter and numerical aperture of the output optical fiber (2); the first high refractive index glue area (4) and the second high refractive index glue area (6) use the same glue, and the refractive index n H ≥1.55; the low refractive index glue area (5) uses a glue with a refractive index n L The range of the low refractive index glue area (5) is ≤1.42, which exceeds the range of the cone area (3); the first high refractive index glue area (4) and the second high refractive index glue area (6) respectively cover the areas near the critical point where the coating of the input optical fiber (1) and the output optical fiber (2) is stripped.

2. The high-power fiber combiner according to claim 1, characterized in that: The length L of the tapered region (3) satisfies the adiabatic tapering criterion.

Images