Double-nested hollow-core anti-resonance optical fiber with off-center structure

Abstract

The invention discloses a double-nested hollow-core anti-resonance optical fiber with an off-center structure, and relates to the technical field of optical communication. The double-nested hollow-core anti-resonance optical fiber sequentially comprises an air core, a first-stage cladding tube, a second-stage cladding tube, a third-stage cladding tube and a peripheral cladding tube from inside to outside, the first-stage cladding tube and the peripheral cladding tube are fixed in an internally tangent manner, the second-stage cladding tube and the first-stage cladding tube are fixed in an internally tangent manner, and the third-stage cladding tube and the second-stage cladding tube are fixed in an internally tangent manner; the optical fiber is of an off-center structure which is vertically symmetrical and bilaterally asymmetrical. Compared with the conventional hollow-core anti-resonance optical fiber, the hollow-core anti-resonance optical fiber with specific structure parameters provided by the invention solves the problem that the conventional hollow-core anti-resonance optical fiber cannot well solve the problem of high bending loss under the condition of extremely short bending radius; the hollow-core optical fiber has relatively low confinement loss and bending loss, and has relatively great application potential in particle sensing and micro lasers.

Description

Technical Field

[0001] The invention belongs to the technical field of optical communication, and in particular relates to a double-nested hollow-core anti-resonant optical fiber with an eccentric center structure. Background Art

[0002] Traditional solid-core optical fibers must overcome some essential limitations in optical transmission, including low material damage threshold, large dispersion, and significant nonlinear effects, especially in the field of high-power laser transmission. Hollow-core antiresonant optical fibers, which utilize the property that most light (>99.99%) can be transmitted in the air core, can increase the optical damage threshold of quartz materials and significantly reduce nonlinear effects. They have attracted great interest in the field of optical fiber communications in the past two decades.

[0003] Chinese patent CN221485655U proposes a new hollow-core anti-resonant optical fiber with multiple anti-resonant layers to maximally confine light waves to propagate in the core, thereby achieving low confinement loss and high-purity single-mode output of light waves. However, its resonant layer uses an elliptical cladding tube, which is extremely difficult to manufacture and is not conducive to high-efficiency production.

[0004] Chinese patent CN111257992A discloses a hollow-core anti-resonant optical fiber with an eccentric structure, which greatly reduces the bending loss of the optical fiber and improves the single-mode transmission characteristics of the optical fiber through the left-right asymmetric cladding structure design. However, in its embodiment 1 and embodiment 2, only a single-layer cladding tube is used, which has a poor loss limiting effect, reduces the output power, and affects the output effect.

[0005] U.S. Patent US2023040327A1 proposes an antiresonant hollow-core optical fiber preform, including an outer cladding, multiple structural tubes and a central support tube. There are multiple connection nodes between the central support tube and the outer cladding tube, which affects the limiting loss and bending loss, and the output effect is poor.

[0006] In summary, traditional solid-core optical fibers cannot solve the scientific problems of nonlinearity and thermal damage well, especially in the field of high-power laser transmission. However, the existing technology involves the design of hollow-core antiresonant optical fibers, which adopt elliptical cladding tubes or other more complex cladding tube designs, which are extremely difficult to manufacture and are not conducive to efficient production; or only a single-layer cladding tube is used, which has a poor loss limiting effect, reduces the output power, and affects the output effect; or there are multiple connection nodes between the outermost cladding tubes, which affects the limiting loss and bending loss, and the output effect is not good. Therefore, the current hollow-core antiresonant optical fibers cannot meet the actual needs of hollow-core antiresonant optical fibers for lower transmission loss and low bending loss in a bent state.

[0007] The present invention proposes a double-nested hollow-core antiresonant optical fiber with an eccentric structure, defines the structural characteristics of the hollow-core antiresonant optical fiber, designs and develops a hollow-core antiresonant optical fiber with specific structural parameters, which not only achieves the goal of confining light of a specific wavelength in the air core for transmission, thereby improving transmission loss, but also reduces bending loss in a short bending radius state, thereby increasing output power. Summary of the invention

[0008] The purpose of the present invention is to provide a double-nested hollow-core antiresonant optical fiber with an eccentric structure to solve the problems mentioned in the above background technology that the traditional solid-core optical fiber in the prior art cannot solve the problems of nonlinearity and thermal damage well, and the existing hollow-core antiresonant optical fiber cannot meet the actual needs of hollow-core antiresonant optical fiber towards lower transmission loss and low bending loss under bending state.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention proposes a double-nested hollow-core anti-resonant optical fiber with an eccentric circular structure, which comprises, from the inside to the outside, an air core, a plurality of first-stage cladding tubes, a plurality of second-stage cladding tubes, a plurality of third-stage cladding tubes and a peripheral cladding tube; the double-nested hollow-core anti-resonant optical fiber presents an eccentric circular structure that is symmetrical up and down and asymmetrical left and right.

[0011] Preferably, the first-stage cladding tube is inscribed and fixed to the outer cladding tube, the second-stage cladding tube is inscribed and fixed to the first-stage cladding tube, and the third-stage cladding tube is inscribed and fixed to the second-stage cladding tube.

[0012] Preferably, the first-stage cladding tubes have no contact with each other, forming a nodeless annular cladding tube; the number of the first-stage cladding tubes is 4 to 10, and the number of the first-stage cladding tubes, the second-stage cladding tubes and the third-stage cladding tubes is the same.

[0013] Preferably, the diameter of the air core is in the range of 20.50 to 40.50 μm.

[0014] Preferably, the radius of the first-stage cladding tube decreases from left to right, and the radius ranges from 9.41 to 25.99 μm.

[0015] Preferably, the ratio of the radius of the second-level cladding tube to the radius of the first-level cladding tube is in the range of 0.500 to 0.900, and the ratio of the radius of the third-level cladding tube to the radius of the second-level cladding tube is in the range of 0.280 to 0.450.

[0016] Preferably, the thickness of the first-stage cladding tube, the second-stage cladding tube and the third-stage cladding tube is in the range of 0.38-0.64 μm in the first resonance range; or in the range of 0.85-1.25 μm in the second resonance range.

[0017] Preferably, the first-stage cladding tube, the second-stage cladding tube and the third-stage cladding tube are all made of glass; the refractive index of the glass at a wavelength of 1550 nm is in the range of 1.4315 to 1.4520, and the rest of the interior of the outer cladding tube is filled with air.

[0018] Furthermore, the glass is made of quartz glass or other component glass.

[0019] Preferably, the anti-resonance region of the double-nested hollow-core anti-resonance optical fiber is in the 1150-1660 nm band, which is used to achieve low-loss transmission and anti-bending properties within its wavelength range.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] In the present invention, the double-nested hollow-core anti-resonant optical fiber is fixed by the first-level cladding tube and the outer cladding tube, the second-level cladding tube and the first-level cladding tube, and the third-level cladding tube and the second-level cladding tube. The double-nested hollow-core anti-resonant optical fiber is symmetrical up and down and asymmetrical left and right. The multi-layer nested structural design is adopted to reduce the transmission loss by increasing the number of resonant layers. The cladding tubes are all circular cladding tubes, which reduces the difficulty of production and increases the reliability of application. There is no contact between the first-level cladding tubes, forming a node-free annular cladding tube to avoid additional losses caused by nodes.

[0022] The hollow-core antiresonant optical fiber with specific structural parameters designed and developed not only achieves the goal of confining light of a specific wavelength in the air core for transmission, improving transmission loss, but also reduces bending loss under short bending radius conditions and increases output power. This hollow-core optical fiber has low confinement loss and bending loss, and has great application potential in particle sensing and micro-lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the cross section of the double-nested hollow-core anti-resonant optical fiber with an eccentric structure in the present invention;

[0024] Figure 2 It is a structural schematic diagram of the cross-section of the first-stage cladding tube, the second-stage cladding tube, and the third-stage cladding tube in the present invention;

[0025] Figure 3 Schematic diagram of a curve showing a change in limiting loss versus wavelength of a double-nested hollow-core antiresonant optical fiber with an eccentric structure in Example 1 of the present invention;

[0026] Figure 4 Schematic diagram of a curve showing a change in bending loss versus bending radius of a double-nested hollow-core antiresonant optical fiber with an eccentric structure in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] See also Figure 1-2 In the present invention, a double-nested hollow-core anti-resonant optical fiber with an eccentric structure includes, from the inside to the outside, an air core, a first-level cladding tube, a second-level cladding tube, a third-level cladding tube and a peripheral cladding tube; the first-level cladding tube is fixed to the peripheral cladding tube, the second-level cladding tube is fixed to the first-level cladding tube, and the third-level cladding tube is fixed to the second-level cladding tube. The double-nested hollow-core anti-resonant optical fiber has an eccentric structure that is symmetrical up and down and asymmetrical left and right. The diameter of the air core ranges from 20.50 to 40.50 μm, and the radius r of the first-level cladding tube from left to right is x The size decreases in sequence, ranging from 9.41 to 25.99 μm. The number of cladding tubes can be 4 to 10, and there is no contact between the first-level cladding tubes, forming a node-free annular cladding tube. The ratio of the radius of the second-level cladding tube to the radius of the first-level cladding tube is r y / r x The range is 0.500~0.900. The ratio of the radius of the third cladding tube to the radius of the second cladding tube is r z / r y The range is 0.280~0.450. The thickness of the first cladding tube, the second cladding tube and the third cladding tube can be within the first resonance range, ranging from 0.38~0.64μm, or within the second resonance range, ranging from 0.85~1.25μm. The material of the cladding tube is glass, which can be quartz glass or other glass. The refractive index n1 of the glass at a wavelength of 1550nm ranges from 1.4315 to 1.4520, and the rest is filled with air. The anti-resonance region of the double-nested hollow-core anti-resonant optical fiber is the 1150~1660nm band. Within this wavelength condition range, the limiting loss is less than 0.10dB / km. When the wavelength is 1550nm, when the bending radius is greater than 3cm, the bending loss is less than 0.05dB / km.

[0029] Embodiment 1:

[0030] See also Figure 1-2The double-nested hollow-core anti-resonant optical fiber with an off-center structure includes, from the inside to the outside, an air core, a first-level cladding tube, a second-level cladding tube, a third-level cladding tube, and an outer cladding tube; the first-level cladding tube is fixed to the outer cladding tube, the second-level cladding tube is fixed to the first-level cladding tube, and the third-level cladding tube is fixed to the second-level cladding tube. There is no contact between the first-level cladding tubes, forming a node-free annular cladding tube to avoid additional losses caused by nodes. The double-nested hollow-core anti-resonant optical fiber has an off-center structure that is symmetrical up and down and asymmetrical left and right.

[0031] In this embodiment, the first-stage cladding tube, the second-stage cladding tube, the third-stage cladding tube and the peripheral cladding tube are all circular cladding tubes, which reduces the difficulty of manufacturing and increases the reliability of application; a multi-layer nested structural design is adopted to reduce transmission loss by increasing the number of resonance layers.

[0032] Specifically, the diameter D of the air core __ The core is 25.50 μm, and the radius of the first-stage cladding tube from left to right is r x1 、r x2 、r x3 The diameters of the first-level cladding tubes are 16.36 μm, 14.23 μm, and 11.71 μm, and there is no contact between the first-level cladding tubes, forming a node-free annular cladding tube.

[0033] Specifically, the ratio of the radius of the second cladding tube to the radius of the first cladding tube is y1 / r x1 、r y2 / r x2 、r y3 / r x3 The ratio of the radius of the third-level cladding tube to the radius of the second-level cladding tube is r z1 / r y1 、r z2 / r y2 、r z3 / r y3 is 0.425.

[0034] In this embodiment, the thickness t of the first-stage cladding tube, the second-stage cladding tube, and the third-stage cladding tube is 0.450 μm.

[0035] In this embodiment, the material of the cladding tube is glass, which can be quartz glass or other glass. The refractive index n1 of the glass at a wavelength of 1550 nm is 1.4440, and the rest is filled with air.

[0036] The antiresonance region of the double-nested hollow-core antiresonant optical fiber in this embodiment is in the 1150-1660 nm wavelength range. Within this wavelength range, please refer to Figure 3In the anti-resonant wavelength range of 1150-1660 nm, the limiting loss is less than 0.10 dB / km, i.e. 1.00×10 -4 dB / m. When the wavelength is 1550nm, the bending loss is less than 0.05dB / km when the bending radius is greater than 3cm. For details, please refer to Figure 4 When the bending radius is greater than 3 cm, the bending loss is less than 0.05 dB / km, i.e. 5.00 × 10 -5 dB / m.

[0037] Embodiment 2:

[0038] See also Figure 1-2 The double-nested hollow-core anti-resonant optical fiber with an off-center structure includes, from the inside to the outside, an air core, a first-level cladding tube, a second-level cladding tube, a third-level cladding tube, and an outer cladding tube; the first-level cladding tube is fixed to the outer cladding tube, the second-level cladding tube is fixed to the first-level cladding tube, and the third-level cladding tube is fixed to the second-level cladding tube. There is no contact between the first-level cladding tubes, forming a node-free annular cladding tube to avoid additional losses caused by nodes. The double-nested hollow-core anti-resonant optical fiber has an off-center structure that is symmetrical up and down and asymmetrical left and right.

[0039] In this embodiment, the first-stage cladding tube, the second-stage cladding tube, the third-stage cladding tube and the peripheral cladding tube are all circular cladding tubes, which reduces the difficulty of manufacturing and increases the reliability of application; a multi-layer nested structural design is adopted to reduce transmission loss by increasing the number of resonance layers.

[0040] Specifically, the diameter D of the air core __ The core is 40.50 μm, and the radius of the first-stage cladding tube from left to right is r x1 、r x2 、r x3 The diameters of the first-level cladding tubes are 25.98 μm, 22.59 μm, and 18.59 μm, and there is no contact between the first-level cladding tubes, forming a node-free annular cladding tube.

[0041] Specifically, the ratio of the radius of the second cladding tube to the radius of the first cladding tube is y1 / r x1 、r y2 / r x2 、r y3 / r x3 The ratio of the radius of the third-level cladding tube to the radius of the second-level cladding tube is r z1 / r y1 、r z2 / r y2 、r z3 / r y3 is 0.450.

[0042] In this embodiment, the thickness t of the first-stage cladding tube, the second-stage cladding tube, and the third-stage cladding tube is 1.25 μm.

[0043] In this embodiment, the material of the cladding tube is glass, which can be quartz glass or other glass. The refractive index n1 of the glass at a wavelength of 1550 nm is 1.4520, and the rest is filled with air.

[0044] The antiresonance region of the double-nested hollow-core antiresonant optical fiber in this embodiment is 1360-1660 nm, and within this wavelength range, the limiting loss is less than 0.09 dB / km. When the wavelength is 1550 nm, the bending loss is less than 0.04 dB / km when the bending radius is greater than 3 cm.

[0045] Embodiment 3:

[0046] See also Figure 1-2 The double-nested hollow-core anti-resonant optical fiber with an off-center structure includes, from the inside to the outside, an air core, a first-level cladding tube, a second-level cladding tube, a third-level cladding tube, and an outer cladding tube; the first-level cladding tube is fixed to the outer cladding tube, the second-level cladding tube is fixed to the first-level cladding tube, and the third-level cladding tube is fixed to the second-level cladding tube. There is no contact between the first-level cladding tubes, forming a node-free annular cladding tube to avoid additional losses caused by nodes. The double-nested hollow-core anti-resonant optical fiber has an off-center structure that is symmetrical up and down and asymmetrical left and right.

[0047] In this embodiment, the first-stage cladding tube, the second-stage cladding tube, the third-stage cladding tube and the peripheral cladding tube are all circular cladding tubes, which reduces the difficulty of manufacturing and increases the reliability of application; a multi-layer nested structural design is adopted to reduce transmission loss by increasing the number of resonance layers.

[0048] Specifically, the diameter of the air core D_core is 20.50 μm, and the radius of the first-stage cladding tube from left to right is r x1 、r x2 、r x3 The diameters of the first-level cladding tubes are 13.15 μm, 11.43 μm, and 9.41 μm, and there is no contact between the first-level cladding tubes, forming a node-free annular cladding tube.

[0049] Specifically, the ratio of the radius of the second cladding tube to the radius of the first cladding tube is y1 / r x1 、r y2 / r x2 、r y3 / r x3 The ratio of the radius of the third-level cladding tube to the radius of the second-level cladding tube is r z1 / r y1 、r z2 / ry2 、r z3 / r y3 It is 0.280.

[0050] In this embodiment, the thickness t of the first-stage cladding tube, the second-stage cladding tube, and the third-stage cladding tube is 0.380 μm.

[0051] In this embodiment, the material of the cladding tube is glass, which can be quartz glass or other glass. The refractive index n1 of the glass at a wavelength of 1550 nm is 1.4315, and the rest is filled with air.

[0052] The antiresonance region of the double-nested hollow-core antiresonant optical fiber in this embodiment is 1150-1560 nm, within this wavelength range, the limiting loss is less than 0.10 dB / km. When the wavelength is 1550 nm, the bending loss is less than 0.05 dB / km when the bending radius is greater than 3 cm.

[0053] In summary, the double-nested hollow-core anti-resonant optical fibers in Examples 1 to 3 of the present invention all satisfy the anti-resonant region of 1150 to 1660 nm, and within this wavelength range, the limiting loss is less than 0.10 dB / km. When the wavelength is 1550 nm, the bending loss is less than 0.05 dB / km when the bending radius is greater than 3 cm. Therefore, the present invention designs and develops hollow-core anti-resonant optical fibers with specific structural parameters, which not only achieves the goal of confining light of a specific wavelength in the air core for transmission, improves transmission loss, but also reduces bending loss in a short bending radius state, thereby increasing output power.

[0054] The above description is only used to help understand the method of the present invention and its core essence, but the protection scope of the present invention is not limited thereto. For those skilled in the art in the art, equivalent replacement or change according to the technical solution and inventive concept of the present invention within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A double-nested hollow-core antiresonant optical fiber with an eccentric structure, characterized in that: From the inside to the outside, it includes: an air core, a plurality of first-level cladding tubes, a plurality of second-level cladding tubes, a plurality of third-level cladding tubes and a peripheral cladding tube; the double-nested hollow-core anti-resonance optical fiber presents an eccentric circular structure that is symmetrical up and down and asymmetrical left and right.

2. The double-nested hollow-core antiresonant optical fiber with an eccentric structure according to claim 1, characterized in that: The first-level cladding tube is inscribed and fixed to the outer cladding tube, the second-level cladding tube is inscribed and fixed to the first-level cladding tube, and the third-level cladding tube is inscribed and fixed to the second-level cladding tube.

3. The double-nested hollow-core antiresonant optical fiber with an eccentric structure according to claim 1, characterized in that: The first-level cladding tubes have no contact with each other, forming a node-free annular cladding tube; the number of the first-level cladding tubes is 4 to 10, and the number of the first-level cladding tubes, the second-level cladding tubes, and the third-level cladding tubes are the same.

4. The double-nested hollow-core antiresonant optical fiber with an eccentric structure according to claim 1, characterized in that: The diameter of the air core is in the range of 20.50 to 40.50 μm.

5. The double-nested hollow-core antiresonant optical fiber with an eccentric structure according to claim 1, characterized in that: The radius of the first-stage cladding tube decreases from left to right, and the radius ranges from 9.41 to 25.99 μm.

6. The double-nested hollow-core antiresonant optical fiber with an eccentric structure according to claim 1, characterized in that: The ratio of the radius of the second-level cladding tube to the radius of the first-level cladding tube is in the range of 0.500 to 0.900, and the ratio of the radius of the third-level cladding tube to the radius of the second-level cladding tube is in the range of 0.280 to 0.

450.

7. The double-nested hollow-core antiresonant optical fiber with an eccentric structure according to claim 1, characterized in that: The thickness of the first-stage cladding tube, the second-stage cladding tube and the third-stage cladding tube is in the range of 0.38-0.64 μm in the first resonance range, or in the range of 0.85-1.25 μm in the second resonance range.

8. The double-nested hollow-core antiresonant optical fiber with an eccentric structure according to claim 1, characterized in that: The first-stage cladding tube, the second-stage cladding tube and the third-stage cladding tube are all made of glass; the refractive index of the glass at a wavelength of 1550nm ranges from 1.4315 to 1.4520, and the rest of the outer cladding tube is filled with air.

9. The double-nested hollow-core antiresonant optical fiber with an eccentric structure according to claim 1, characterized in that: The anti-resonance region of the double-nested hollow-core anti-resonance optical fiber is in the 1150-1660 nm band.

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