CN-121978812-A - Middle infrared fluoride optical fiber end cap packaging device

CN121978812ACN 121978812 ACN121978812 ACN 121978812ACN-121978812-A

Abstract

The invention relates to the technical field of optical fiber devices and discloses a middle infrared fluoride optical fiber end cap packaging device which comprises a cover plate, a gas chamber, an optical fiber clamping assembly and a sleeve, wherein the cover plate, the gas chamber, the optical fiber clamping assembly and the sleeve are sequentially arranged along the axial direction, the gas chamber is used for providing a gas environment and actively controlling the gas environment, the two ends of the gas chamber are respectively sealed and packaged by the cover plate and the optical fiber clamping assembly, the optical fiber clamping assembly is used for clamping a fluoride optical fiber in a radial and axial positioning mode and is assembled into the gas chamber together, an air charging and discharging nozzle is assembled on the optical fiber clamping assembly in a sealing mode, and the sleeve is assembled on the optical fiber clamping assembly in a coaxial positioning mode and is assembled on the gas chamber. The incident laser is conducted through the fluoride optical fiber, sequentially passes through the end part of the sleeve, the optical fiber clamping assembly and the gas chamber, and finally is output through an optical window on the cover plate. A dry, inert, physically isolated working environment is provided and maintained for the vapor sensitive fluoride fiber end cap by an active gas control environment.

Inventors

ZHANG BIN
JIANG QIANQIAN
HOU JING
HONG WEIDE
YANG LINYONG
CHEN ZILUN
SONG RUI
YANG XIAONING
LIANG HENGYU

Assignees

中国人民解放军国防科技大学

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (10)

1. The middle infrared fluoride optical fiber end cap packaging device is characterized by comprising a cover plate (100), a gas chamber (200), an optical fiber clamping assembly (300) and a sleeve (400) which are sequentially arranged along the axial direction; the gas chamber (200) is used for providing a gas environment and actively controlling the gas environment, two ends of the gas chamber (200) are respectively sealed and packaged by adopting a cover plate (100) and an optical fiber clamping assembly (300), the optical fiber clamping assembly (300) is used for clamping a fluoride optical fiber in a radial and axial positioning manner and is assembled into the gas chamber (200) together, the gas filling and discharging nozzle (500) is assembled on the optical fiber clamping assembly (300) in a sealing manner, the sleeve (400) is assembled on the optical fiber clamping assembly (300) in a coaxial positioning manner and the optical fiber clamping assembly (300) is assembled on the gas chamber (200); The incident laser is conducted through the fluoride optical fiber, sequentially passes through the end part of the sleeve (400), the optical fiber clamping assembly (300) and the gas chamber (200), and finally is output through an optical window on the cover plate (100).
2. The mid-infrared fluoride optical fiber end cap packaging device according to claim 1, further comprising a bottom plate (600), wherein a fixing positioning member (601) for positioning and assembling the gas chamber (200) on the bottom plate (600) along the vertical direction of the bottom plate (600) is arranged on the side wall of the gas chamber (200), and the device is ensured to be in a stable and horizontally placed state during operation through the fixing positioning member (601).
3. The mid-infrared fluoride optical fiber end cap packaging device according to claim 1, wherein a first through hole (101) for installing a window sheet or a lens is formed in the center of the cover plate (100), and the window sheet or the lens is sealed and adhered to the first through hole (101) through ultraviolet glue; The periphery of a first through hole (101) of the cover plate (100) is provided with a first annular boss (102), and the first annular boss (102) is used for pressing the sealing rubber ring (700) when the cover plate (100) is assembled; A plurality of first connecting pieces (103) are uniformly distributed on the periphery of the cover plate (100), and the cover plate (100) is fixedly connected to the first end of the gas chamber (200) in a centered and positioned mode through the first connecting pieces (103) and enables the first annular boss (102) to press the sealing rubber ring (700).
4. A mid-infrared fluoride optical fiber end cap packaging device according to claim 3, wherein a first end of the gas chamber (200) is provided with a first annular groove (201), a second connecting piece (202) and a second through hole (203), the first annular groove (201) is correspondingly arranged with the first annular boss (102), the second connecting piece (202) is correspondingly arranged with the first connecting piece (103) one by one and is fixedly connected, and the second through hole (203) is coaxially arranged with the first through hole (101); The second end of the gas chamber (200) is provided with a second annular groove (204), a third connecting piece (205) and a waist-shaped hole (206), the waist-shaped hole (206) is positioned in the middle of the second end of the gas chamber (200) and is used for the fiber clamping assembly (300) to penetrate, the second annular groove (204) is positioned at the periphery of the waist-shaped hole (206) and is used for accommodating the sealing rubber ring (700) so as to realize the sealing between the gas chamber (200) and the fiber clamping assembly (300), and a plurality of third connecting pieces (205) are circumferentially arranged at intervals at the periphery of the second annular groove (204) and are used for realizing the fixed connection of centering positioning between the gas chamber (200) and the fiber clamping assembly (300).
5. The mid-infrared fluoride fiber end cap package device of any one of claims 1 to 4, wherein the fiber clamping assembly (300) comprises a connection plate (301), a metal armor (302), and a press block (303); The metal armor (302) is arranged in the middle of the connecting plate (301) and penetrates through the connecting plate (301), an optical fiber clamp groove (3021) is formed in the metal armor (302), the optical fiber clamp groove (3021) is arranged as a multi-stage stepped hole groove, fluoride optical fibers welded with the fluoride end caps are arranged in the metal armor (302) through multi-stage steps Kong Caorong, and a protective sleeve is sleeved outside the optical fibers of the fluoride optical fibers; The fluoride optical fiber is vertically pressed on the multi-stage stepped hole groove of the metal armor (302) through the pressing block (303), and the assembly gap between the metal armor (302) and the connecting plate (301) is sealed by injecting ultraviolet glue.
6. The mid-infrared fluoride optical fiber end cap packaging device according to claim 5, wherein a third through hole (3011) is formed in the connecting plate (301), and the third through hole (3011) is located at one side of the metal armor (302) facing away from the optical fiber clamp groove (3021); And the third through hole (3011) is provided with an air charging and discharging nozzle (500), and the air charging and discharging nozzle (500) is used for being connected with an external air source or a vacuum pump.
7. The mid-infrared fluoride optical fiber end cap packaging device according to claim 5, wherein a second annular boss (3012) is arranged at the periphery of the metal armor (302) of the connecting plate (301), and the second annular boss (3012) is used for pressing the sealing rubber ring (700) when the optical fiber clamping assembly (300) is assembled; A plurality of fourth connecting pieces (3013) are uniformly distributed on the periphery of the connecting plate (301), the connecting plate (301) is fixedly connected to the second end of the gas chamber (200) in a centered and positioned mode through the fourth connecting pieces (3013), and the second annular boss (3012) is enabled to press the sealing rubber ring (700).
8. The mid-infrared fluoride optical fiber end cap packaging device according to any one of claims 1 to 4, wherein the sleeve (400) comprises a cylindrical section (401) and a conical section (402), the sleeve (400) is connected to the outer peripheral wall of the optical fiber clamping assembly (300) through internal threads of the cylindrical section (401), so that the centering positioning and fixing connection of the gas chamber (200), the optical fiber clamping assembly (300) and the sleeve (400) is realized, and the conical tip of the conical section (402) is provided with a penetrating hole.
9. The mid-infrared fluoride fiber end cap package device of any one of claims 1 to 4, wherein the cover plate (100), the gas chamber (200), the fiber clamping assembly (300) and the sleeve (400) are all fabricated from 6061 aluminum alloy material.
10. The mid-infrared fluoride fiber end cap package of any one of claims 1 to 4, wherein the actual end cap length of the fluoride fiber is controlled to be less than a theoretical value to ensure reduced power density while minimizing beam divergence due to multimode transmission and ensuring good output beam quality.

Description

Middle infrared fluoride optical fiber end cap packaging device Technical Field The invention relates to the technical field of optical fiber devices, in particular to a middle infrared fluoride optical fiber end cap packaging device. Background The fiber laser and the amplifier have wide application value in the fields of biomedicine, industrial manufacturing, spectral analysis and the like. The high-power fiber laser working in the mid-infrared band (especially in the wavelength range of 3-5 μm) has unique advantages in the application scene because the emitted laser is matched with the characteristic absorption peaks of various materials. However, the practical progress of such lasers faces a long-standing technical hurdle that the output end, particularly the end cap portion of the optical fiber, is susceptible to degradation of the performance or even irreversible physical damage under the long-term action of high-power laser, resulting in degradation of the output power and the quality of the light beam, and eventually leading to failure of the whole laser system. The core of this problem is the "photo-thermal degradation" effect of the output facet, and fluoride fibers are particularly problematic due to their intrinsic material properties. Fluoride glass is a gain medium and an energy-transfer medium commonly used for mid-infrared fiber lasers. Although it has a low intrinsic absorption in the target band, its chemical nature is relatively active. When the end face of the fiber (i.e., the end face of the output end cap) is exposed to the operating environment, it reacts with moisture in the environment. This process not only causes physical degradation of the end-face microstructure (e.g., microcracking), but more importantly introduces hydroxyl groups (OH -). The hydroxyl group has strong intrinsic absorption peak in the mid-infrared band, especially in the range of 2.7 μm-3.0 μm and the vicinity. Under high power density laser irradiation, these introduced hydroxyl groups become locally strong absorption centers. The absorbed light energy is rapidly converted into heat energy, resulting in a sharp local temperature rise. The high temperature further accelerates the chemical reaction rate of the end face material and the moisture in the environment, and more hydroxyl is introduced to form a vicious circle of absorption enhancement, temperature rise aggravation and reaction acceleration, namely a photo-thermal degradation process. Eventually, localized heat build-up may cause the end face material to melt, structurally fail, or cause nonlinear effects, resulting in permanent damage. Therefore, the contact between water vapor and the end face of the optical fiber is fundamentally blocked, and the key of guaranteeing the long-term reliable operation of the mid-infrared optical fiber laser is provided. Prior art to solve this problem, research is mainly conducted in two directions: The first category focuses on the selection of more environmentally resistant end cap materials to replace or protect the deliquescent fluoride fiber end face. Specifically, (a) other types of fluoride glasses are used, such as zirconium fluoride (ZrF 4) based or indium fluoride (InF 3) based glasses. The material has good fusion compatibility with fluoride gain optical fibers, low initial optical loss, but the hydroxyl diffusion and adsorption resistance of the material is still weak, and the requirement of high-power long-term operation is difficult to meet. (b) An oxide material such as germanium oxide (GeO 2) optical fiber or fused silica (SiO 2) optical fiber is used. The germanium oxide optical fiber has certain water vapor erosion resistance in a mid-infrared band, but has higher refractive index, and can generate higher Fresnel reflection at an air interface, so that extra insertion loss is brought, and reflected light can be coupled back to a laser resonant cavity to influence the stability of a laser. In addition, the material cost is high, and the long-term stability is still to be improved. Fused silica optical fibers, although being inexpensive, excellent in processability and extremely stable in chemical properties, have a high intrinsic absorption in the mid-infrared band, particularly around 3 μm. Under high power lasers, even if not attacked by moisture, the heat generated by its own absorption may cause the end cap temperature to exceed the safe operating threshold of the material, resulting in package failure. (c) Monocrystalline materials such as calcium fluoride (CaF 2), sapphire (Al 2O3), and the like are used. Crystalline materials generally have excellent chemical stability and thermal conductivity, but are extremely difficult to process, difficult to make into complex shapes that match optical fibers, and reliable, low loss fusion splicing with optical fibers presents a significant technical challenge and is costly. The second approach is to provide a physically isolated packaging environment for the