TW202102887A

TW202102887A - Method of splicing optical fibers and structure of spliced optical fiber

Info

Publication number: TW202102887A
Application number: TW108124555A
Authority: TW
Inventors: 蔡宗祐
Original assignee: 國立成功大學
Priority date: 2019-07-11
Filing date: 2019-07-11
Publication date: 2021-01-16
Also published as: TWI691745B

Abstract

The present invention therefore provides a method of splicing optical fibers. First, a first optical fiber and a second optical fiber are provided, wherein a core diameter of the first optical fiber is smaller than a core diameter of the second optical fiber. After performing a hydrogen loading treatment for the first optical fiber; a thermal expansion core (TEC) treatment is performed for the first optical fiber and the second optical fiber to match the mode-field (MF) of the first optical fiber and the second optical fiber at the fused section between the first optical fiber and the second optical fiber. The present invention further provides a spliced optical fiber, including a first optical fiber part, a second optical fiber part, and a fused section.

Description

光纖熔接的方法與熔接光纖Optical fiber fusion splicing method and fusion splicing optical fiber

本發明係關於一種光纖熔接的方式，特別是一種包含載氫處理步驟的光纖熔接的方式。本發明還關於一種熔接光纖結構。The present invention relates to an optical fiber fusion splicing method, particularly an optical fiber fusion splicing method including a hydrogen-carrying treatment step. The invention also relates to a fusion splicing optical fiber structure.

具有熔接（fusion-spliced）光纖元件的單體系統（monolithic system）不需麻煩的對準和定期維護，由於內部並無氣隙，其內部熔融元件間腔呈現菲涅耳反射（Fresnel reflection）可使其具有低耗損之優點。由於電弧接頭技術的成熟，目前已可以輕易地將多種光纖元件組裝置而形成一單體光纖系統（monolithic fiber system）。然而，對於一些大模場面積（large field-mode area, LMA）光纖，例如高功率光纖雷射（high power fiber laser）和被動Q切換光纖雷射（passively Q-switched fiber laser）而言，需要精密的光纖接合技術例如熱熔拉法（fiber tapering）或熱擴張纖核法（thermally diffused expanded core, TEC），以用於末端的模場（mode field, MF）適配。熱擴張纖核法方法已經被大量地研究，並應用於各種設備，如模場適配器（MF adaptor），泵組合器（pump combiner），雷射二極體光纖耦合器（fiber couplers for laser diodes）以及雙芯纖維的模場耦合（mode coupling in twin-core fiber）中。與光纖熱融拉法不同的是，光纖熱融拉法系對披覆層（cladding layer）給予一物理變化，但熱擴張纖核法是以氫氧焰加熱小纖核之光纖，以迫使該纖核部分的摻質擴散。在纖核膨脹至所需模場面積後，將光纖的加熱部分切割並拼接於另一種大模場面積光纖。對於石英光纖，其纖核面積係由摻質決定，當使用鍺(Ge)時，其擴散係數在1400°C時約為1×10^-15 m² /s。在此溫度下，能將有效纖核直徑從4微米（μm）擴展到10μm的加熱時間會超過一小時。如此長時間的加熱且加熱溫度超過玻璃熔點的情況下，光纖容易因自身的重力而導致其變形，使加熱區過於脆弱並難以承受後續之模場適配過程。The monolithic system with fusion-spliced optical fiber components does not require troublesome alignment and regular maintenance. Since there is no internal air gap, the cavity between the internal fusion-spliced components exhibits Fresnel reflection. It has the advantage of low loss. Due to the maturity of arc splicing technology, it is now possible to easily install a variety of optical fiber component groups to form a monolithic fiber system. However, for some large field-mode area (LMA) fibers, such as high power fiber lasers and passively Q-switched fiber lasers, it is necessary to Precision fiber splicing techniques such as fiber tapering or thermally diffused expanded core (TEC) are used for end-of-mode field (MF) adaptation. The thermal expansion core method has been extensively studied and applied to various devices, such as MF adaptor, pump combiner, and fiber couplers for laser diodes. And the mode coupling in twin-core fiber. Different from the optical fiber thermal drawing method, the optical fiber thermal drawing method imparts a physical change to the cladding layer, but the thermal expansion core method heats the optical fiber of the small core with a hydrogen-oxygen flame to force the Dopants diffuse in the core part. After the core expands to the required mode field area, the heated part of the fiber is cut and spliced to another large mode field fiber. For silica fiber, the area of the core is determined by the dopant. When germanium (Ge) is used, its diffusion coefficient is about 1×10 ^-15 m ² /s at 1400°C. At this temperature, the heating time that can extend the effective core diameter from 4 microns (μm) to 10 μm will exceed one hour. When heating for such a long time and the heating temperature exceeds the melting point of the glass, the fiber is easily deformed due to its own gravity, making the heating zone too fragile and difficult to withstand the subsequent mode field adaptation process.

相形之下，電弧引起的熱擴張纖核法(arc-induced TEC)很少受到關注。由於電弧所形成纖核擴張區域僅有約幾百微米，為了在如此短的纖核擴張區域中實現絕熱（無損耗）模場轉變，兩種不匹配光纖之間的模場比受到嚴格限制。此外，過小的纖核擴張區域在後期切割過程也難以實行，因此要進行模場適配，只能透過施加電弧在兩個不匹配光纖的弧形交叉處來完成，使交叉處的兩個光纖的纖核同時被處理並且以相同的電弧功率熱膨脹。儘管存在一些缺點，但由於使用電弧法之模場適配過程可以在幾十秒內成完，其仍被認為是快速有效的方法之一。In contrast, arc-induced TEC (arc-induced TEC) has received little attention. Since the core expansion area formed by the arc is only about a few hundred microns, in order to achieve adiabatic (lossless) mode field transition in such a short core expansion area, the mode field ratio between the two mismatched fibers is strictly limited. In addition, the too small core expansion area is difficult to implement in the later cutting process. Therefore, the mode field adaptation can only be completed by applying an arc at the arc-shaped intersection of two mismatched fibers, so that the two fibers at the intersection The nuclei are processed at the same time and thermally expanded with the same arc power. Although there are some shortcomings, since the mode field adaptation process of the arc method can be completed in tens of seconds, it is still considered to be one of the fast and effective methods.

本發明於是提供了一種涉及模場適配過程的方法，可以使熔接後兩個光纖間的耗損降低。The present invention thus provides a method involving the mode field adaptation process, which can reduce the loss between two optical fibers after fusion splicing.

本發明於是提供了一種光纖熔接(Fusion splicing)的方法。提供一第一光纖以及一第二光纖，該第一光纖之纖核直徑小於該第二光纖之纖核直徑，然後對第一光纖進行一載氫處理。後續，對第一光纖以及該第二光纖進行一熱擴散纖核(thermal expansion core, TEC)處理，使在接合切面的該第一光纖之模場匹配於該第二光纖之模場。The present invention thus provides a method of fiber fusion splicing (Fusion splicing). A first optical fiber and a second optical fiber are provided, the core diameter of the first optical fiber is smaller than the core diameter of the second optical fiber, and then a hydrogen-carrying treatment is performed on the first optical fiber. Subsequently, a thermal expansion core (TEC) process is performed on the first optical fiber and the second optical fiber, so that the mode field of the first optical fiber at the splicing section matches the mode field of the second optical fiber.

本發明還另外提供了一種熔接光纖，包含：一第一光纖部分，具有一第一纖核層；一第二光纖部分，具有一第二纖核層，第一纖核層之直徑小於第二纖核層之直徑，第一光纖部分包含有氫，第二光纖部分實質上不包含有氫；一熔接切面，設置在第一光纖部分與第二光纖部分相接處，熔接切面的第一光纖部分之模場與第二光纖部分之模場相匹配。The present invention also provides a fusion spliced optical fiber, including: a first optical fiber part having a first core layer; a second optical fiber part having a second core layer, the diameter of the first core layer is smaller than the second core layer The diameter of the core layer, the first optical fiber part contains hydrogen, and the second optical fiber part does not substantially contain hydrogen; a fusion splicing section is provided at the junction of the first optical fiber section and the second optical fiber section, and the first optical fiber of the fusion section is fused The mode field of the part matches the mode field of the second optical fiber part.

為使本發明所屬技術領域中具有通常知識者可以進一步了解本發明，在以下的描述中會列出本發明的較佳實施例，並配合圖式，詳細說明本發明的構成內容及所欲實現之效果。In order to enable those with ordinary knowledge in the technical field of the present invention to further understand the present invention, the following description will list the preferred embodiments of the present invention, and in conjunction with the drawings, describe in detail the content of the present invention and the intended implementation. The effect.

本發明是關於一種光纖熔接的方法。請參考第1圖至第3圖，所繪示為本發明一種光纖熔接的步驟示意圖。本方法包含如下的步驟：The invention relates to a method for optical fiber fusion splicing. Please refer to FIG. 1 to FIG. 3, which are schematic diagrams of the steps of optical fiber fusion splicing according to the present invention. This method includes the following steps:

如第1圖所示，首先提供一第一光纖300以及一第二光纖400。第一光纖300與第二光纖400例如是單模(single mode)光纖，且由二氧化矽(SiO₂ )所組成。第一光纖300具有一披覆層(cladding layer)302與一纖核層(core layer)304，第二光纖400具有一披覆層402與一纖核層404，纖核層304與纖核層404中具有半導體摻質，例如是鍺。可以理解的是，第一光纖300中纖核層304的範圍係由其中的半導體摻質來界定，第二光纖400亦同。本發明由於係應用在光纖之熔接，因此兩光纖的纖核直徑（core diameter）會不同，如第1圖所示，第一光纖300中的纖核層304的纖核直徑d₁ 小於第二光纖400中纖核層404的纖核直徑d₂ 。而於一實施例中，第一光纖300的外徑D₁ 等於第二光纖400的外徑D₂ ，而於另一實施例中，外徑D₁ 也可以不同於外徑D₂ 。於一實施例中，第一光纖300與第二光纖400的模場面積比值為1.3~16。As shown in Figure 1, first, a first optical fiber 300 and a second optical fiber 400 are provided. The first optical fiber 300 and the second optical fiber 400 are, for example, single-mode optical fibers, and are composed of silicon dioxide (SiO ₂ ). The first optical fiber 300 has a cladding layer 302 and a core layer 304, the second optical fiber 400 has a cladding layer 402 and a core layer 404, and the core layer 304 and the core layer 404 contains semiconductor dopants, such as germanium. It can be understood that the range of the core layer 304 in the first optical fiber 300 is defined by the semiconductor dopants therein, and the second optical fiber 400 is the same. Since the present invention is applied to the fusion splicing of optical fibers, the core diameters of the two optical fibers will be different. As shown in Figure 1, the core diameter d _{1 of the} core layer 304 in the first optical fiber 300 is smaller than that of the second optical fiber. _{The core diameter d 2 of the} core layer 404 in the optical fiber 400. In one embodiment, the outer diameter D _{1 of the} first optical fiber 300 is equal to the outer diameter D _{2 of the} second optical fiber 400. In another embodiment, the outer diameter D ₁ may be different from the outer diameter D ₂ . In one embodiment, the ratio of the mode field area of the first optical fiber 300 to the second optical fiber 400 is 1.3-16.

如第2圖所示，將第一光纖300進行一載氫處理500。載氫處理500係指任何可以將氫原子注入光纖中並與纖核中的摻質產生鍺-氫之空乏中心 (germanium-oxygen deficiency centers, GODC) 效應之技術。於一實施例中，載氫處理是將第一光纖300置於一高壓氫環境中，使氫原子滲透進第一光纖300。高壓氫環境例如1200磅每平方英寸（pound per square inch或pound-force per square inch, psi）~2000 psi，時間進行約4~14天。As shown in Figure 2, the first optical fiber 300 is subjected to a hydrogen-carrying treatment 500. Hydrogen-carrying treatment 500 refers to any technology that can inject hydrogen atoms into the fiber and generate germanium-oxygen deficiency centers (GODC) effects with the dopants in the fiber core. In one embodiment, the hydrogen-carrying treatment involves placing the first optical fiber 300 in a high-pressure hydrogen environment to allow hydrogen atoms to penetrate into the first optical fiber 300. High-pressure hydrogen environment such as 1200 pounds per square inch (pound per square inch or pound-force per square inch, psi) ~ 2000 psi, the time is about 4 to 14 days.

如第3圖所示，對第一光纖300與第二光纖400進行一熱擴散纖核(thermal expansion core, TEC)處理。於一實施例中，熱擴散纖核處理可以使用電弧、氫氧焰、準分子雷射或二氧化碳雷射。而於本發明較佳實施例中，熱擴散纖核處理係以電弧（arc）來進行，其溫度可達攝氏1800度～2000度，持續時間為2~20秒，使第一光纖300與第二光纖400在由兩電極之間的電弧區域（通常約0.4公釐）進行適配。值得注意的是，有別於習知熱光纖熱熔拉法（fiber tapering），若使用電弧加熱時，並不需額外對光纖施以額外拉力。如第3圖所示，第一光纖300與第二光纖400在熱擴散纖核處理後，其纖核層304與纖核層404中的摻質會擴散，並在電弧放電處彼此接合。由於第一光纖300有施以載氫處理，其摻質擴散速率由於鍺-氫之空乏中心 (germanium-oxygen deficiency centers, GODC) 效應而增加，故雖然第一光纖300之纖核直徑d1小於第二光纖400之纖核直徑d2，在第一光纖300中摻質擴散速度大於第二光纖400中摻質擴散速度的情況下，最終在熔接切面的第一光纖300的纖核直徑會趨近於第二光纖400的纖核直徑，使兩光纖具有匹配之模場直徑（mode field diameter），而完成理想的適配。於一實施例中，第一光纖300之模場擴散速率為4~20 x10^-8 cm² /s。值得注意的是，模態場直徑匹配（Match of the Mode field diameters guided in the two fiber cores）與纖核直徑與數值孔徑兩者有關，而數值孔徑是由纖核和纖核外部的折射係數差異所決定。例如兩相同直徑但具有不同鍺摻雜濃度的纖核相比，摻鍺較高的纖核會有較高的數值孔徑 (NA值)，其模態直徑會比較小。於本發明較佳實施例中，由於較佳是使用單模光纖，模態場直徑會略大但是很接近纖核直徑，因此本發明所稱之模態場匹配亦可稱為纖核匹配。另一方面，模態場匹配可以通過量測第一光纖與第二光纖之間的傳輸率來界定（相關量測方式在下文中描述）。於一實施例中，第一光纖300與第二光纖400的模場面積比值為0.9~1.1，而第一光纖300與第二光纖400之間的傳輸率為0.9~1。As shown in FIG. 3, the first optical fiber 300 and the second optical fiber 400 are processed with a thermal expansion core (TEC). In one embodiment, the thermal diffusion core treatment may use electric arc, oxyhydrogen flame, excimer laser or carbon dioxide laser. In the preferred embodiment of the present invention, the thermal diffusion core treatment is carried out by an electric arc (arc), the temperature of which can reach 1800 degrees to 2000 degrees Celsius, and the duration is 2 to 20 seconds. The two optical fibers 400 are fitted in the arc area (usually about 0.4 mm) between the two electrodes. It is worth noting that, unlike the conventional fiber tapering method, if arc heating is used, no additional tension is required on the fiber. As shown in FIG. 3, after the thermal diffusion core treatment of the first optical fiber 300 and the second optical fiber 400, the dopants in the core layer 304 and the core layer 404 of the first optical fiber 300 and the second optical fiber 400 will diffuse and join each other at the arc discharge. Since the first optical fiber 300 is subjected to hydrogen-carrying treatment, its dopant diffusion rate is increased due to the germanium-oxygen deficiency centers (GODC) effect. Therefore, although the core diameter d1 of the first optical fiber 300 is smaller than that of the first optical fiber 300, the dopant diffusion rate is increased due to the germanium-oxygen deficiency centers (GODC) effect. The core diameter d2 of the second optical fiber 400. In the case that the dopant diffusion speed in the first optical fiber 300 is greater than the dopant diffusion speed in the second optical fiber 400, the core diameter of the first optical fiber 300 at the fusion splicing section will be close to The core diameter of the second optical fiber 400 enables the two optical fibers to have a matching mode field diameter, thereby achieving an ideal fit. In one embodiment, the mode field diffusion rate of the first optical fiber 300 is 4-20×10 ^-8 cm ² /s. It is worth noting that Match of the Mode field diameters guided in the two fiber cores is related to both the core diameter and the numerical aperture, while the numerical aperture is determined by the difference in refractive index between the core and the outside of the core. Decided. For example, compared to two cores with the same diameter but with different doping concentrations of germanium, the core doped with higher germanium will have a higher numerical aperture (NA value), and its modal diameter will be smaller. In the preferred embodiment of the present invention, since it is better to use a single-mode fiber, the modal field diameter will be slightly larger but very close to the core diameter. Therefore, the modal field matching referred to in the present invention can also be referred to as core matching. On the other hand, the modal field matching can be defined by measuring the transmission rate between the first optical fiber and the second optical fiber (the related measurement methods are described below). In an embodiment, the ratio of the mode field area of the first optical fiber 300 to the second optical fiber 400 is 0.9-1.1, and the transmission rate between the first optical fiber 300 and the second optical fiber 400 is 0.9-1.

通過上述方法，即可形成一熔接之光纖結構。如第3圖所示，熔接之光纖包含有一第一光纖部分（即原來之第一光纖300），具有一第一纖核層304。一第二光纖部分（即原來之第二光纖400），具有一第二纖核層404，第一纖核層304之直徑小於該第二纖核層404之直徑。熔接切面700位在第一光纖部分300與第二光纖部分400相接處。如前文所述，在經過熱纖核擴散處理後，位在熔接切面700的第一光纖部分之模場與第二光纖部分400之模場相匹配。由於光纖中之模場範圍與纖核層呈正相關，故本領域具有通常之知識者也可以理解，此處（熔接切面700）的第一光纖部分之第一纖核層304也會對應於第二光纖部分之第二纖核層404，使兩者在熔接切面700的面積與位置能大體上相同。此外，第一纖核層304在靠近熔接切面700呈現一第一椎體306，第一椎體306具有一第一高度H₁ ，第一椎體306與熔接切面700具有一角度α；第二纖核層404在靠近熔接切面700呈現一第二椎體406，第二椎體406具有一第二高度H₂ 。由於第一光纖300以載氫處理，擴散臨界溫度也降低，所以遠離電弧中心處仍有很明顯的擴散，故第一錐體306之第一高度H₁ 大於第二椎體406之第二高度H₂ 。並且，載氫處理後之第一纖核層302，也因為摻質擴散速度之差異，而有結構上之不同。請參考第3圖與第4圖，其中第4圖是未經過載氫處理的熔接光纖的示意圖。從此兩圖之比較可知，由於載氫處理之摻質擴散速度較快，第3圖（經過載氫處理）之角度α大於與第4圖（未經過載氫處理）之角度α₀ ，使第一椎體306之拉錐斜率變小。於較佳實施例中，角度α趨近於90度，例如是87.5 ~89.9度。由於第一椎體306具有較小的拉錐斜率，可有利於模態場轉變，降低耗損進而增加光纖之傳輸率，藉以得到更好品質之熔接光纖。Through the above method, a fusion spliced optical fiber structure can be formed. As shown in Figure 3, the fusion spliced optical fiber includes a first optical fiber part (ie, the original first optical fiber 300) with a first core layer 304. A second optical fiber part (ie, the original second optical fiber 400) has a second core layer 404, and the diameter of the first core layer 304 is smaller than the diameter of the second core layer 404. The fusion splicing section 700 is located where the first fiber portion 300 and the second fiber portion 400 meet. As mentioned above, after the thermal core diffusion treatment, the mode field of the first optical fiber part located on the fusion cut surface 700 matches the mode field of the second optical fiber part 400. Since the mode field range in the optical fiber is positively correlated with the core layer, those with ordinary knowledge in the art can also understand that the first core layer 304 of the first optical fiber part here (fusion section 700) will also correspond to the first core layer 304. The second core layer 404 of the two optical fiber parts makes the area and position of the two optical fiber sections substantially the same. In addition, the first core layer 304 presents a first vertebral body 306 near the welding section 700, the first vertebral body 306 has a first height H ₁ , and the first vertebral body 306 and the welding section 700 have an angle α; The core layer 404 presents a second vertebral body 406 close to the fusion cut surface 700, and the second vertebral body 406 has a second height H ₂ . Since the first optical fiber 300 is treated with hydrogen, the diffusion critical temperature is also reduced, so there is still significant diffusion away from the center of the arc, so the first height H _{1 of the} first cone 306 is greater than the second height of the second cone 406 H ₂ . Moreover, the first core layer 302 after the hydrogen-carrying treatment also has a structural difference due to the difference in the diffusion rate of the dopants. Please refer to Figures 3 and 4. Figure 4 is a schematic diagram of a fusion spliced optical fiber that has not undergone hydrogen-carrying treatment. From the comparison of the two figures, it can be seen that due to the faster diffusion rate of dopants in hydrogen-carrying treatment, the angle α in Fig. 3 (with hydrogen-carrying treatment) is greater than the angle α _{0 in} Fig. 4 (without hydrogen-carrying treatment), so that The tapering slope of a cone 306 becomes smaller. In a preferred embodiment, the angle α approaches 90 degrees, for example, 87.5 to 89.9 degrees. Since the first cone 306 has a smaller tapering slope, it can facilitate the transition of the modal field, reduce loss and increase the transmission rate of the optical fiber, so as to obtain a better quality fusion spliced optical fiber.

由於載氫過程可以應用在光纖接合上，使兩光纖之接合時間縮短，可以形成低耗損高品質的光纖元件，適合應用在各種需要光纖接合的光學元件上，例如以共振腔以及布拉格光柵（fiber Bragg grating, FBG）組成之Q切換脈衝雷射光發射器，或是其他高功率雷射，但並不以此為限。為了證明上述方式確實能降低光纖接合之穿透率損耗，下文將描述實驗內容加以驗證。Since the hydrogen-carrying process can be applied to optical fiber splicing, the splicing time of two optical fibers can be shortened, and low-loss and high-quality optical fiber components can be formed. It is suitable for various optical components that require optical fiber splicing, such as resonant cavities and Bragg gratings. Bragg grating, FBG) composed of Q-switched pulsed laser light emitters, or other high-power lasers, but not limited to this. In order to prove that the above method can indeed reduce the transmittance loss of fiber splicing, the following will describe the experimental content to verify.

為了監測電弧熱擴張纖核法之瞬間熔接的傳輸損耗，並排除由功率波動和波長靈敏度引起的不準確性，本實施例設計了一測量系統，請參考第5圖。在第5圖中，功率分配器（power splitter）接到一自製之1030奈米連續鐿摻雜光纖雷射器（1030 nm CW Yb-doped fiber laser），作為光源使用。雷射功率設定為3毫瓦（mW）。功率分配器300的一個端口連接至一光纖樣品（光纖A。功率分配器300的兩端口間的功率比R_ref = P₁ / P₀ 首先確定為1.53，標準偏差為0.2％。在電弧熱擴張纖核處理期間，通過測量兩個輸出端口之間的功率比R_m = P₂ / P₀ 來獲得光纖A和B之間的接頭傳輸率T_m = R_m / R_ref 。In order to monitor the instantaneous splicing transmission loss of the arc thermal expansion fiber core method, and eliminate the inaccuracy caused by power fluctuations and wavelength sensitivity, this embodiment designs a measurement system, please refer to Figure 5. In Figure 5, the power splitter is connected to a self-made 1030 nm continuous Ytterbium-doped fiber laser (1030 nm CW Yb-doped fiber laser) as a light source. The laser power is set to 3 milliwatts (mW). One port of the power splitter 300 is connected to a fiber sample (fiber A. The power ratio R _ref = P ₁ / P ₀ between the two ports of the power splitter 300 is first determined to be 1.53, with a standard deviation of 0.2%. In the arc thermal expansion _{During core processing, the joint transmission rate T m} = R _m / R _ref between fibers A and B is obtained by measuring the power ratio R _m = P ₂ / P ₀ between the two output ports.

在本實施例中，光纖B係由Liekki公司生產之型號為P10/125-08的大纖核單模和單包覆層光纖，光纖A係由康寧公司生產之行號為Hi980的小單模態光纖（single mode fiber, SMF）。同時，對原始的Hi980和載氫處理後的Hi980進行了比較測試。光纖B（P10/125-08）的纖核直徑為10μm，數值孔徑（numerical aperture, NA）為0.08；小纖核光纖Hi980的纖核直徑為3.5μm，數值孔徑為0.21。根據馬爾庫塞方程（Marcuse’s equation），1030奈米處的模場面積計算為9.3×10^-7 cm² （A_ob ，針對光纖B）和1.28×10^-7 cm² （A_oa ，針對光纖A），兩者之間的模場面積比為7.25。載氫過程係將光纖A（Hi980）裝入具有1700psi的高壓的純氫氣瓶中2週，然後從氣瓶移出後約30小時進行測試。後續使用的光纖拼接器（fiber splicer）是由Fitel公司製造的S178 LDF。光纖A和光纖B用標準的單模-單模（SMF-SMF）電弧程序拼接，然後在相同的拼接接頭上逐步手動添加電弧而不進行移位和拉伸。在S178 LDF中，電弧功率範圍從0到200，預設值為100（機器規格中未顯示真正的功率數值）。然而即便在不同拼接器廠商中，標準單模-單模拼接所需的電弧功率應該相同，故可作為標準化功率參考。在本實驗中，每個弧段（arc step）的功率設置為100，然後與輸出性能最相關的參數是總累積弧持續時間（total accumulated arc duration）。記錄每次施加電弧後的傳輸率（transmission），並最終繪製成如第6圖之曲線。第6圖繪示了測量使用光纖Hi980和載氫處理之光纖Hi980與光纖BP10/125-08拼接的任一種情況的三種典型傳輸曲線。預設每個電弧的持續時間為750毫秒。然而，由於原始光纖Hi980的擴散速率較慢，故每個附加電弧的持續時間設定為2秒。Y軸所表示的傳輸耗損值（單位：分貝dB）對比於x軸表示的累積弧持續時間（單位：秒）。在光纖P10/125-08拼接未處理之光纖Hi980的情況下，電弧熱擴散纖核處理的最大傳輸率約為81.5％（即-0.89dB），其所需之累積電弧持續時間約27±2秒。若光纖P10/125-08拼接載氫處理之光纖Hi980，最佳傳輸率增加到94.6%（即-0.24dB），平均累積電弧持續時間縮短為9.8秒。In this embodiment, optical fiber B is a large-core single-mode and single-clad fiber with the model number P10/125-08 produced by Liekki, and optical fiber A is a small single-mode with the line number Hi980 produced by Corning. Mode fiber (single mode fiber, SMF). At the same time, the original Hi980 and the hydrogen-carrying Hi980 were compared and tested. Fiber B (P10/125-08) has a core diameter of 10μm and a numerical aperture (NA) of 0.08; the small core fiber Hi980 has a core diameter of 3.5μm and a numerical aperture of 0.21. According to Marcuse's equation, the mode field area at 1030 nm is calculated as 9.3×10 ^-7 cm ² (A _ob , for fiber B) and 1.28×10 ^-7 cm ² (A _oa , for fiber A ), the mode field area ratio between the two is 7.25. The hydrogen-carrying process is to load optical fiber A (Hi980) into a pure hydrogen cylinder with a high pressure of 1700 psi for 2 weeks, and then perform the test about 30 hours after it is removed from the cylinder. The subsequent fiber splicer (fiber splicer) is S178 LDF manufactured by Fitel. Optical fiber A and optical fiber B are spliced using a standard single-mode-single-mode (SMF-SMF) arc procedure, and then an arc is manually added to the same splicing joint without shifting and stretching. In S178 LDF, the arc power range is from 0 to 200, and the default value is 100 (the actual power value is not shown in the machine specifications). However, even among different splicer manufacturers, the arc power required for standard single-mode-single-mode splicing should be the same, so it can be used as a standard power reference. In this experiment, the power of each arc step is set to 100, and then the parameter most relevant to the output performance is the total accumulated arc duration. Record the transmission after each application of the arc, and finally draw the curve as shown in Figure 6. Figure 6 shows three typical transmission curves for measuring any of the splicing of optical fiber Hi980 and hydrogen-carrying optical fiber Hi980 and optical fiber BP10/125-08. The preset duration of each arc is 750 milliseconds. However, since the diffusion rate of the original fiber Hi980 is relatively slow, the duration of each additional arc is set to 2 seconds. The transmission loss value (unit: dB) shown on the Y-axis is compared with the cumulative arc duration (unit: seconds) on the x-axis. In the case of fiber P10/125-08 splicing untreated fiber Hi980, the maximum transmission rate of arc thermal diffusion core treatment is about 81.5% (ie -0.89dB), and the required cumulative arc duration is about 27±2 second. If fiber P10/125-08 is spliced with hydrogen-carrying fiber Hi980, the best transmission rate is increased to 94.6% (ie -0.24dB), and the average cumulative arc duration is shortened to 9.8 seconds.

另一方面，如果在一個長弧（long arc）步驟中執行拼接和熱擴散纖核處理而不是施加多段短弧(multiple-step short arcs)，則可以實現-0.24dB的傳輸，甚至可將電弧持續時間縮短為8秒。但須注意的是在每個電弧步驟中還存有一預熔融持續時間，意指將光纖從室溫加熱至熔點之時間，即摻雜劑沒有進行擴散之時段。在本實施例中，此預熔融預設是設定為160毫秒（ms）。因此可以理解的是，前述以一個長弧步驟來執行熱擴散纖核處理可以取得較佳結果（在8秒內-0.24dB傳輸耗損）可歸因於較少的預熔融時間。此外，由於兩光纖之模場區域不匹配，徑向偏移和角度不對準引起的兩根光纖間的熔接損耗可以通過拼接光纖中模場幅度的重疊積分來計算。假設是理想對準的情況下，僅由模場區域不匹配所引起的傳輸損耗T_MFA 可由下面方程式（I）來表示：

方程式（I）其中R_A 是兩個拼接光纖的模場面積比。因此若根據方程式（I），若光纖P10/125-08與未處理之光纖Hi980光纖拼接而沒有纖核擴散時（即R_Ao = 7.25），理論傳輸損耗為-3.71 dB。On the other hand, if splicing and thermal diffusion core processing are performed in a long arc step instead of applying multiple-step short arcs, a transmission of -0.24dB can be achieved, and even the arc can be reduced. The duration is reduced to 8 seconds. However, it should be noted that there is a pre-melting duration in each arc step, which means the time for heating the fiber from room temperature to the melting point, that is, the period during which the dopant is not diffused. In this embodiment, the pre-melting preset is set to 160 milliseconds (ms). Therefore, it can be understood that the foregoing thermal diffusion core treatment with one long arc step can achieve better results (-0.24dB transmission loss within 8 seconds), which can be attributed to the shorter pre-melting time. In addition, due to the mismatch of the mode field regions of the two fibers, the splicing loss between the two fibers caused by the radial offset and angular misalignment can be calculated by the overlap integral of the mode field amplitudes in the spliced fibers. Under the assumption of ideal alignment, the transmission loss T _MFA caused only by the mode field area mismatch can be expressed by the following equation (I):

Formula (I) wherein R _A is a ratio of the mode field area of two spliced fibers. Therefore, according to equation (I), if fiber P10/125-08 is spliced with untreated fiber Hi980 fiber without core diffusion (ie R _Ao = 7.25), the theoretical transmission loss is -3.71 dB.

從第6圖可以得知，光纖以載氫處理後可以增強鍺擴散速率，其量化和分析如下，並請一併參考表一。首先，在選-1.5 dB的傳輸損耗下比較兩種情況，其中由熱擴散纖核過渡區斜率引起的損耗可以忽略不計（相關討論請參考第8圖和後文之討論）。利用方程式（I）可以推導出熱擴散纖核處理的模場面積比R_A,tec 在-1.5dB的耗損基礎上之值為3.35。對於載氫處理之光纖Hi980和原始Hi980的情況，若欲達成-1.5dB的傳輸損耗，其累積電弧持續時間分別為2.25秒和10.75秒。將累積電弧持續時間減去預融合持續時間（即：2.25-0.16×3以及10.75-0.16×6），兩組光纖之有效擴散持續時間分別為1.77秒和9.79秒（在表一中分別標示為τ_d,h 和τ_d,o ）。表一電弧前載氫Hi980 P10/125-08 傳輸率T_o -3.71 dB 模場面積比 7.25(R_Ao ) 模場直徑 4.04μm 10.88μm 模場區域 1.28×10^-7 cm² (A_oa ) 9.3×10^-7 cm² (A_ob ) 電弧後載氫Hi980 P10/125-08 未載氫Hi980 P10/125-08 傳輸率T_TEC -1.5dB 模場面積比 3.35(R_A,tec ) 累積電弧持續時間（秒） 2.25(τ_ac,h ) 10.75(τ_ac,o ) 有效擴散時間（秒） 1.77(τ_d,h ) 9.79(τ_ac,h ) 熱擴散模場面積差異（cm² ） 1.61×10^-7 (ΔA_HL ) 3.85×10^-8 (ΔA_S ) 2.13×10^-7 (ΔA_o ) 2.13×10^-7 (ΔA_o ) 模場擴散速率（cm² /s） 9.09×10^-8 2.18×10^-8 2.18×10^-8 2.18×10^-8 It can be seen from Figure 6 that the diffusion rate of germanium can be enhanced after the optical fiber is treated with hydrogen. The quantification and analysis are as follows, and please refer to Table 1. First, compare the two cases with a transmission loss of -1.5 dB, where the loss caused by the slope of the transition zone of the thermal diffusion fiber core is negligible (for related discussion, please refer to Figure 8 and the following discussion). Equation (I) can be used to deduce the mode field area ratio R _A of the thermal diffusion core treatment, and the value of tec is 3.35 based on the loss of -1.5dB. For the hydrogen-carrying fiber Hi980 and the original Hi980, if you want to achieve a transmission loss of -1.5dB, the cumulative arc duration is 2.25 seconds and 10.75 seconds, respectively. Subtracting the cumulative arc duration from the pre-fusion duration (ie: 2.25-0.16×3 and 10.75-0.16×6), the effective diffusion duration of the two groups of fibers are 1.77 seconds and 9.79 seconds (respectively marked as τ _d,h and τ _d,o ). Table I Before the arc Hydrogen Hi980 P10/125-08 Transmission rate T _o -3.71 dB Mode field area ratio 7.25(R _Ao ) Mode field diameter 4.04μm 10.88μm Mode field area 1.28×10 ^-7 cm ² (A _oa ) 9.3×10 ^-7 cm ² (A _ob ) After arc Hydrogen Hi980 P10/125-08 No hydrogen Hi980 P10/125-08 Transmission rate T _TEC -1.5dB Mode field area ratio 3.35(RA _,tec ) Cumulative arc duration (seconds) 2.25(τ _ac,h ) 10.75(τ _ac,o ) Effective diffusion time (seconds) 1.77(τ _d,h ) 9.79(τ _ac,h ) Area difference of thermal diffusion mode (cm ² ) 1.61×10 ^-7 (ΔA _HL ) 3.85×10 ^-8 (ΔA _S ) 2.13×10 ^-7 (ΔA _o ) 2.13×10 ^-7 (ΔA _o ) Mode field diffusion rate (cm ² /s) 9.09×10 ^-8 2.18×10 ^-8 2.18×10 ^-8 2.18×10 ^-8

由於光纖P10/125-08和未處理之光纖Hi980具有相同的鍺擴散常數（cm² /s），且兩者之模場面積差異（ΔA_o ）係隨擴散而增加，故透過下方的方程式(II)，將電弧處理後之模場面積比設定為3.35（由方程式(II)推得），可推導熱擴散模場面積差異應為2.13×10^-7 cm² 。

方程式(II)Since the fiber P10/125-08 and the untreated fiber Hi980 have the same germanium diffusion constant (cm ² /s), and the mode field area difference (ΔA _o ) between the two increases with diffusion, the following equation ( II), the mode field area ratio after arc treatment is set to 3.35 (derived from equation (II)), and it can be inferred that the difference in thermal diffusion mode field area should be 2.13×10 ^-7 cm ² .

Equation (II)

而在載氫處理後之光纖Hi980拼接光纖P10/125-08的情況，由於擴散持續時間較短，光纖P10/125-08中增加的面積ΔA_s 為3.85×10^-8 cm² （由ΔA_o ×(τ_d,h )/τ_d,o 而來）。為達到相同的參考模場比率3.35，根據下面的方程式(III)，載氫光纖Hi980中的熱擴散模場面積差異ΔA_HL 應為1.61×10^-7 cm² 。

方程式(III)In the case of fiber Hi980 spliced fiber P10/125-08 after hydrogen-carrying treatment, due to the shorter diffusion duration, the increased area ΔA _s in fiber P10/125-08 is 3.85×10 ^-8 cm ² (from ΔA _o ×(τ _{d, h} )/τ _{d, o} ). In order to achieve the same reference mode field ratio of 3.35, according to the following equation (III), the thermal diffusion mode field area difference ΔA _HL in the hydrogen-carrying fiber Hi980 should be 1.61×10 ^-7 cm ² .

Equation (III)

因此，估計載氫處理後光纖Hi980的模場膨脹率約為原始未處理之光纖Hi980的4.2倍。Therefore, it is estimated that the mode field expansion rate of the fiber Hi980 after hydrogen-carrying treatment is about 4.2 times that of the original untreated fiber Hi980.

使用載氫處理光纖的主要優點為，除了電弧後之熱擴散纖核區域面積增加以外，在拼接交叉處之間摻質擴散速率的差異亦可減少傳輸損耗並縮短了處理時間。為了證明這些優點，我們捕捉拼接光纖電弧熔合區附近的圖像以確定其纖核擴展之情況。如第7圖所示，將未處理之光纖Hi980和載氫處理之光纖Hi980拼接在一起，以比較電弧熱擴散纖核處理1.5秒、3秒和6秒之不同累積電弧持續時間的情況。拼接器拍攝的照片如第7圖(a)~(c)所示。纖核輪廓係由圖中最接近纖核明亮中心的最暗點定義出來，並相對應地計算出纖核直徑以及變化，如第7圖(d)～(f)所示。The main advantage of using hydrogen-carrying fiber to process the fiber is that, in addition to the increase in the area of the thermal diffusion core area after the arc, the difference in dopant diffusion rate between the splicing intersections can also reduce the transmission loss and shorten the processing time. In order to prove these advantages, we captured images near the arc fusion zone of the spliced fiber to determine its core expansion. As shown in Figure 7, the untreated fiber Hi980 and the hydrogen-carrying fiber Hi980 were spliced together to compare the different cumulative arc durations of 1.5 seconds, 3 seconds, and 6 seconds of arc thermal diffusion core treatment. The photos taken by the stitcher are shown in Figure 7(a)~(c). The contour of the nucleus is defined by the darkest point closest to the bright center of the nucleus, and the diameter and change of the nucleus are calculated accordingly, as shown in Figure 7 (d) ~ (f).

如第7圖所示，載氫處理的光纖Hi980的纖核直徑在6秒內擴展至10μm，具有相對大的過渡區域。與未處理之光纖Hi980比較，載氫處理後鍺擴散速率大大增加。在本實施例中。由於光纖是置於兩電極棒之間（請再次參考第3圖與相關段落之說明），並使用電擊棒的尖端放電，因此電弧的區域不大，約0.4公釐而且在電弧區域中心點溫度最高 (約攝氏2000度)，一離開中心點，受熱溫度會急速下降。而實際情況如第7圖可看到，在載氫光纖的遠離電弧處中心處 (電弧溫度較低處)纖核仍然有很明顯的擴散。由此可見光纖載氫後可降低 Ge 的擴散臨界溫度。然而需注意的是，上述以輪廓來定義臨界尺寸（critical dimension, CD）的方法，當臨界尺寸較小時，其判斷結果會受限於圖像之解析度。例如官方公佈之原始光纖Hi980的測量尺寸應為5μm，而不是本方法所測得之3.5μm。因此，實際上未處理光纖Hi980的熱擴散纖核區域應比第7圖(d)~(f)中顯示的要大。然而即便有上述解析度上的限制，但是這並不會影響到鍺擴散速率和擴散趨勢差異的判斷。As shown in Figure 7, the core diameter of the hydrogen-carrying fiber Hi980 expands to 10 μm in 6 seconds, with a relatively large transition area. Compared with the untreated fiber Hi980, the germanium diffusion rate is greatly increased after hydrogen-carrying treatment. In this embodiment. Since the optical fiber is placed between the two electrode rods (please refer to the description in Figure 3 and related paragraphs again), and the tip of the electric shock rod is used for discharge, the arc area is not large, about 0.4 mm and the temperature at the center point of the arc area The highest (approximately 2000 degrees Celsius), once it leaves the center point, the heated temperature will drop rapidly. In the actual situation, as shown in Figure 7, the core of the hydrogen-carrying fiber far away from the arc (where the arc temperature is lower) still has significant diffusion. It can be seen that the diffusion critical temperature of Ge can be reduced after the fiber is loaded with hydrogen. However, it should be noted that the above method of defining the critical dimension (CD) by contour, when the critical dimension is small, the judgment result will be limited by the resolution of the image. For example, the official measurement size of the original optical fiber Hi980 should be 5μm instead of 3.5μm measured by this method. Therefore, in fact, the thermal diffusion core area of the untreated fiber Hi980 should be larger than that shown in Figure 7 (d) ~ (f). However, even with the above resolution limitation, this will not affect the judgment of the difference in germanium diffusion rate and diffusion trend.

為了進一步了解損耗原因和電弧引起之模場適配的限制，我們把光纖A和B更改為相同類型的光纖，並把兩者拼接後以電弧持續處理直到產生大規模的傳輸損耗。本實驗針對對三種光纖類型（載氫處理之光纖Hi980，未處理之光纖Hi980和光纖P10/125-08）進行了測試，並記錄其傳輸降級曲線(transmission degrading curve)呈現如第8圖。由於模場不匹配和其他未對準因素的損失可以忽略不計，後來出現的損耗應該可直接等同於熱擴散纖核區域漸增的過渡斜率（以由L_slp 表示）。以第8圖來說，相較於如第5圖中以光纖Hi980拼接光纖P10/125-08的情況，第8圖所是的損耗部分L_slp 應該是光纖P10/125-08和光纖Hi980的兩條曲線的平均值。例如，在最佳電弧持續時間為27秒（見第6圖）時，損耗L_slp 預計約為-0.23 dB（即第8圖中曲線的平均值為0.13和0.33）。另一方面，對於載氫處理之光纖Hi980接合光纖P10/125-08的情況，損耗L_slp 在最佳電弧持續時間為9.8秒（見第6圖）的情況下僅為-0.03 dB，且從光纖P10 / 125-08端幾乎沒有損失。值得注意的是，在此損耗部分L_slp 為-0.03dB，優於第6圖中的-0.24dB的實驗數據，顯示除了Lslp和模場尺寸不匹配之外尚存有其他的損耗機制。為何有0.21 dB的損耗間隙尚不清楚，在此推論可能是一維電弧放電所導致的不對稱纖核擴展，因為理想的模場適配不僅在區域尺寸上要配合，還涉及到於兩個不匹配光纖連接處的形狀。也就是說，如果用更對稱的加熱源（例如三電極電弧接合器）對光纖進行熱擴散纖核處理，則應進一步改善傳輸率。In order to further understand the cause of loss and the limitation of the mode field adaptation caused by the arc, we changed the fibers A and B to the same type of fiber, and after splicing the two, continued treatment with the arc until large-scale transmission loss occurred. This experiment tested three fiber types (hydrogen-carrying fiber Hi980, untreated fiber Hi980 and fiber P10/125-08), and recorded their transmission degrading curve as shown in Figure 8. Since the loss of mode field mismatch and other misalignment factors is negligible, the loss that appears later should be directly equivalent to the increasing transition slope of the thermal diffusion core area ( _{indicated by L slp} ). Taking Figure 8 as an example, compared to the case of splicing optical fiber P10/125-08 with optical fiber Hi980 in Figure 5, the loss part L _slp shown in Figure 8 should be that of optical fiber P10/125-08 and optical fiber Hi980. The average of the two curves. For example, when the optimal arc duration is 27 seconds (see Figure 6), the loss L _slp is expected to be about -0.23 dB (that is, the average value of the curve in Figure 8 is 0.13 and 0.33). On the other hand, for the hydrogen-carrying fiber Hi980 spliced fiber P10/125-08, the loss L _slp is only -0.03 dB when the optimal arc duration is 9.8 seconds (see Figure 6), and from There is almost no loss of fiber P10/125-08 end. It is worth noting that the loss part L _slp is -0.03dB, which is better than the experimental data of -0.24dB in Figure 6, which shows that there are other loss mechanisms besides Lslp and the mode field size mismatch. It is not clear why there is a loss gap of 0.21 dB. It is inferred here that it may be the asymmetric core expansion caused by one-dimensional arc discharge, because the ideal mode field adaptation not only needs to match the area size, but also involves two Does not match the shape of the fiber connection. In other words, if a more symmetrical heating source (such as a three-electrode arc splicer) is used for thermal diffusion core treatment of the optical fiber, the transmission rate should be further improved.

綜上所述，本發明顯示了以電弧熱擴散纖核方法之模場適配，可以通過對小纖核光纖加載氫氣處理來得到較佳成果。在模場適配中當兩不匹配光纖之模場面積比在7.25的情況下，9.8秒的累積電弧持續時間內，傳輸損耗從理論值-3.71dB減小到-0.24dB。載氫處理之二氧化矽光纖的摻質鍺擴散速率估計為未處理的的4.2倍。由於載氫處理可增強鍺的擴散速率，可以在非常短的電弧時間內有效地實現兩個纖核直徑大小不同光纖之間的模場適配，其中光纖形狀可以保持不變。鍺擴散速率加大的物理原因係由於鍺位置附近的氫分子和高電弧溫度引起的鍺-氧空位缺陷（germanium-oxygen vacancy）。可以預期使用各種熱源，例如CO₂ 雷射器和O₂ -H₂ 火焰，也可以同樣達成模場適配的增強。In summary, the present invention shows that the mode field adaptation of the arc thermal diffusion core method can obtain better results by applying hydrogen treatment to the small core fiber. In the mode field adaptation, when the mode field area ratio of the two mismatched fibers is 7.25, the transmission loss is reduced from the theoretical value -3.71dB to -0.24dB during the cumulative arc duration of 9.8 seconds. The diffusion rate of doped germanium in the hydrogen-carrying silicon dioxide fiber is estimated to be 4.2 times that of the untreated one. Since hydrogen-carrying treatment can enhance the diffusion rate of germanium, the mode field adaptation between two fibers with different core diameters can be effectively realized in a very short arc time, and the shape of the fiber can be kept unchanged. The physical reason for the increase in germanium diffusion rate is the germanium-oxygen vacancy caused by the hydrogen molecules near the germanium position and the high arc temperature. It can be expected that various heat sources, such as CO ₂ lasers and O ₂ -H ₂ flames, can also be used to achieve enhanced mode field adaptation.

300:第一光纖 304,404:纖核層 400:第二光纖 500:載氫處理 302,402:披覆層 600:熱擴散纖核處理 306:第一椎體 700:熔接切面 406:第二椎體300: The first fiber 304,404: core layer 400: second fiber 500: Hydrogen treatment 302, 402: Coating layer 600: Thermal diffusion core treatment 306: first vertebral body 700: Welding section 406: second vertebral body

第1圖至第3圖繪示了本發明一種光纖熔接的方法示意圖。第4圖是未經過載氫處理的熔接光纖的示意圖。第5圖繪示了本發明實驗中設計的測量系統的示意圖，用以測量電弧熱擴張纖核法之瞬間熔接損耗。第6圖繪示了測量使用光纖Hi980和載氫處理之光纖Hi980與光纖BP10/125-08拼接的任一種情況的二種典型傳輸曲線。第7圖(a)~(c)繪示了拼接之未處理光纖Hi980(左)與載氫處理之光纖Hi980(右)在電弧熱擴散纖核過程第1.5秒、3秒和6秒的照片，(d)~(f)繪示了對應纖核直徑隨著時間變化的折線圖。第8圖繪示了在三種光纖類型（載氫處理之光纖Hi980，未處理之光纖Hi980和光纖P10/125-08）之傳輸耗損曲線。Figures 1 to 3 show schematic diagrams of an optical fiber fusion splicing method according to the present invention. Figure 4 is a schematic diagram of a fusion spliced optical fiber that has not undergone hydrogen-carrying treatment. Figure 5 shows a schematic diagram of the measurement system designed in the experiment of the present invention to measure the instantaneous splicing loss of the arc thermal expansion core method. Figure 6 shows two typical transmission curves for measuring either the fiber Hi980 and the hydrogen-carrying fiber Hi980 spliced with the fiber BP10/125-08. Figure 7(a)~(c) shows the photos of spliced untreated fiber Hi980 (left) and hydrogen-carrying fiber Hi980 (right) during the arc thermal diffusion core process at 1.5 seconds, 3 seconds and 6 seconds , (D)~(f) shows the corresponding line graph of the change of core diameter over time. Figure 8 shows the transmission loss curves of the three fiber types (hydrogen-carrying fiber Hi980, unprocessed fiber Hi980 and fiber P10/125-08).

300:第一光纖 300: The first fiber

400:第二光纖 400: second fiber

302,402:披覆層 302, 402: Coating layer

306:第一椎體 306: first vertebral body

304,404:纖核層 304,404: core layer

600:熱擴散纖核處理 600: Thermal diffusion core treatment

700:熔接切面 700: Welding section

406:第二椎體 406: second vertebral body

Claims

一種光纖熔接的方法，包含：提供一第一光纖以及一第二光纖，該第一光纖之纖核直徑小於該第二光纖之纖核直徑；對該第一光纖進行一載氫處理；以及對該第一光纖以及該第二光纖進行一熱擴散纖核(thermal expansion core, TEC)處理，使在位於該第一光纖與該第二光纖之間的一熔接切面處的該第一光纖與該第二光纖之模場互相匹配。A method of optical fiber fusion splicing, including: Providing a first optical fiber and a second optical fiber, the core diameter of the first optical fiber is smaller than the core diameter of the second optical fiber; Performing a hydrogen-carrying treatment on the first optical fiber; and Perform a thermal expansion core (TEC) treatment on the first optical fiber and the second optical fiber, so that the first optical fiber at a fusion cut surface between the first optical fiber and the second optical fiber is The mode fields of the second optical fiber are matched with each other.

如申請專利範圍第1項所述之光纖熔接的方法，其中該載氫處理包含將該第一光纖置於一高壓氫環境，該高壓氫環境之壓力為1200psi~2000psi。According to the method of optical fiber fusion splicing described in claim 1, wherein the hydrogen-carrying treatment includes placing the first optical fiber in a high-pressure hydrogen environment, and the pressure of the high-pressure hydrogen environment is 1200psi~2000psi.

如申請專利範圍第1項所述之光纖熔接的方法，其中該第二光纖並未進行載氫處理。In the optical fiber fusion splicing method described in item 1 of the scope of the patent application, the second optical fiber is not subjected to hydrogen carrying treatment.

如申請專利範圍第1項所述之光纖熔接的方法，其中該第一光纖以及該第二光纖內具有一摻質，該摻質的分布分別對應該第一光纖以及該第二光纖的纖核直徑，在進行該熱擴散纖核處理時，該第一光纖內的該摻質的擴散速率大於該第二光纖內的該摻質的擴散速率。The method for fusion splicing of optical fibers as described in item 1 of the scope of patent application, wherein the first optical fiber and the second optical fiber have a dopant, and the distribution of the dopant corresponds to the cores of the first optical fiber and the second optical fiber, respectively Diameter, during the thermal diffusion core treatment, the diffusion rate of the dopant in the first optical fiber is greater than the diffusion rate of the dopant in the second optical fiber.

如申請專利範圍第1項所述之光纖熔接的方法，其中該熱擴散纖核處理包含使用電弧、氫氧焰、準分子雷射或二氧化碳雷射。The method for fusion splicing of optical fibers as described in the first item of the patent application, wherein the thermal diffusion core treatment includes the use of electric arc, oxyhydrogen flame, excimer laser or carbon dioxide laser.

如申請專利範圍第1項所述之光纖熔接的方法，其中該方法係用於形成脈衝雷射光的被動式Q開關機制。The method of optical fiber fusion splicing as described in item 1 of the scope of patent application, wherein the method is used to form a passive Q-switch mechanism of pulsed laser light.

如申請專利範圍第1項所述之光纖熔接的方法，其中在進行該熱擴散纖核處理前，該第一光纖與該第二光纖的模場面積比值為1.3~16。According to the method of optical fiber fusion splicing described in item 1 of the scope of patent application, before the thermal diffusion core processing is performed, the ratio of the mode field area of the first optical fiber to the second optical fiber is 1.3-16.

如申請專利範圍第1項所述之光纖熔接的方法，其中在進行該熱擴散纖核處理後，該第一光纖與該第二光纖的模場面積比值為0.9~1.1。According to the method of optical fiber fusion splicing described in item 1 of the scope of patent application, after the thermal diffusion core treatment is performed, the ratio of the mode field area of the first optical fiber to the second optical fiber is 0.9-1.1.

如申請專利範圍第1項所述之光纖熔接的方法，其中在進行該熱擴散纖核處理後，該第一光纖與該第二光纖之間的傳輸率為0.9~1。According to the method of optical fiber fusion splicing described in item 1 of the scope of patent application, after the thermal diffusion core treatment is performed, the transmission rate between the first optical fiber and the second optical fiber is 0.9-1.

如申請專利範圍第1項所述之光纖熔接的方法，其中該熱擴散纖核處理之累積電弧持續時間為2~20秒。As for the method of optical fiber fusion splicing described in item 1 of the scope of patent application, the cumulative arc duration of the thermal diffusion core treatment is 2-20 seconds.

如申請專利範圍第1項所述之光纖熔接的方法，其中在進行該熱擴散纖核處理時，該第一光纖之模場擴散速率為4~20 x10^-8 cm² /s。According to the method of optical fiber fusion splicing described in item 1 of the scope of patent application, when the thermal diffusion core is processed, the mode field diffusion rate of the first optical fiber is 4-20 x 10 ^-8 cm ² /s.

一種熔接光纖，包含：一第一光纖部分，具有一第一纖核層；一第二光纖部分，具有一第二纖核層，該第一纖核層之直徑小於該第二纖核層之直徑，該第一光纖部分包含有氫，該第二光纖部分實質上不包含有氫；以及一熔接切面，設置在該第一光纖部分與該第二光纖部分相接處，該熔接切面的該第一光纖部分之模場與該第二光纖部分之模場相匹配。A fusion splicing optical fiber, including: A first optical fiber part having a first core layer; A second optical fiber portion has a second core layer, the diameter of the first core layer is smaller than the diameter of the second core layer, the first optical fiber portion contains hydrogen, and the second optical fiber portion does not substantially contain Has hydrogen; and A fusion splicing section is arranged at the junction of the first optical fiber part and the second optical fiber section, and the mode field of the first optical fiber part of the fusion splicing section matches the mode field of the second optical fiber part.

如申請專利範圍第12項所述之熔接光纖，其中該第一光纖部分與該第二光纖部分的模場面積比值為0.9~1.1。As for the fusion spliced fiber described in item 12 of the scope of patent application, the ratio of the mode field area of the first fiber portion to the second fiber portion is 0.9-1.1.

如申請專利範圍第12項所述之熔接光纖，其中該第一光纖部分與該第二光纖部分間的傳輸率為0.9~1。As for the fusion spliced optical fiber described in item 12 of the scope of patent application, the transmission rate between the first optical fiber part and the second optical fiber part is 0.9-1.

如申請專利範圍第12項所述之熔接光纖，其中：該第一纖核層在靠近該熔接切面呈現一第一椎體，該第一椎體具有一第一高度；該第二纖核層在靠近該熔接切面呈現一第二椎體，該第二椎體具有一第二高度，該第一高度大於該第二高度。As the fusion spliced optical fiber described in item 12 of the scope of patent application, of which: The first core layer presents a first vertebral body near the fusion cut surface, and the first vertebral body has a first height; The second core layer presents a second vertebral body near the fusion cut surface, and the second vertebral body has a second height, and the first height is greater than the second height.

如申請專利範圍第15項所述之熔接光纖，其中該第一椎體與該熔接切面間具有一角度，該角度為87.5 ~89.9度。According to the fusion splicing optical fiber described in item 15 of the scope of patent application, there is an angle between the first vertebral body and the fusion tangent plane, and the angle is 87.5-89.9 degrees.