200407575 玖、發明說明： [發明所屬之技術領域】 本發明係關於光纖熔接。詳言之，本發明係關於一種光 纖熔接，於此熔接中，至少其中一根光纖具一與其餘已熔 融光纖之模場直徑（MFD)匹配之被控制模場直徑（MFD)擴大 比率。 [先前技術] 熔接係使用一電弧將兩光纖之端面焊接在一起。其目的 係使光纖匹配以獲得可能之最低訊號損失。可使用極高之 溫度（〜2,00(TC)熔化此兩根光纖之矽玻璃端面，接著該等端 面可被安置在一起且可進行冷卻及溶融。單模光纖要求光 纖纖芯具有精確之校準。為使光損失減至最小，需要匹配 此兩光纖之模場直徑（MFD)。使用極其複雜的計算機控制設 備進行光纖校準及光匹配之監控。 摻餌光纖（EDF)對於熔接來說是個特殊的挑戰，因其要求 小纖芯及高數值孔徑以使效率達到最大，從而藉此減小模 場直徑（MFD)。此問題進而由於位於摻餌光纖（edf)及將與 摻餌光纖（EDF)接合之光纖中離子摻雜劑之擴散率不同（例 如該等於摻餌光纖放大器（EDFA)泵浦混波器中所發現之擴 散率）而趨於複雜化。 、 先前應用於摻_光纖（EDF)接合之方法係關於藉由將指奏 升高之離子擴散至纖芯以外，從而有意擴大具較小模二 徑（猶)之光纖之模場直徑（MFD)，以匹配第二光纖之^ 直徑（削）。指數升高之離子擴散具降低該芯層之折射指^ 85076 -6- 254 200407575 同時增大纖芯有效尺寸之雙重效應。 然而，當吾人需擴大該模場直徑（MFD)時，通常證實難 以控制所發生之擴大比率。該降低折射指數同時增大纖芯 尺寸之雙重效應使得於正確的時間停止模場直徑（MFD)之擴 大過程變得極為困難。例如，當一放大器製造商使用摻餌 光纖（EDF)時，他們可能會遇到因用以使模場直徑充 分擴大之溶融時間過短而無法提供足夠之機械強度之問 題。此外，短熔融時間使得對該熔接機之容許度控制變得 困難，從而導致重接性問題之發生。 當孩熔接機因位於電極上之矽發生·積聚而產生之變化（熔 融電流、電弧位置及電弧穩定度之變化）因使非穩定性達到 平衡 < 熔融時間之縮短而具有一更大影響時，該匹配問題 甚而變得更為複雜。 先前之諸多努力均專注於嘗試提高一纖芯之擴大（及因此 提高模場直徑(MFD))而非減緩之。一實例揭示出一使用氟 擴散至-纖芯以減少該纖芯相對於包層之折射指數差異， 藉此提高該模場直徑(MFD)之擴大比率之設計。另一相關實 例描述-種為增大模場直徑⑽D)而有意擴散指數升高之纖 芯摻雜物以最佳化接合損失之方法。 仍需要-種常規匹配模場直徑⑽D)之溶接及一種用以 達成此熔接之可重複方法。 [發明内容]200407575 2. Description of the invention: [Technical field to which the invention belongs] The present invention relates to optical fiber fusion splicing. In detail, the present invention relates to a splicing of optical fibers. In this splicing, at least one of the optical fibers has a controlled mode field diameter (MFD) expansion ratio that matches the mode field diameter (MFD) of the remaining fused fibers. [Prior Art] Welding uses an electric arc to weld the end faces of two optical fibers together. The purpose is to match the fibers to get the lowest possible signal loss. Extremely high temperatures (~ 2,00 (TC) can be used to melt the silica glass end faces of these two fibers, and then the end faces can be placed together and cooled and melted. Single-mode fibers require precise fiber cores Calibration. In order to minimize light loss, it is necessary to match the mode field diameter (MFD) of the two fibers. The use of extremely complex computer-controlled equipment for fiber calibration and light matching monitoring. The bait-doped fiber (EDF) is a splice A special challenge, because it requires a small core and a high numerical aperture to maximize efficiency, thereby reducing the mode field diameter (MFD). This problem in turn is due to the presence of edf-doped fibers (EDFs) and EDF) The diffusivity of ion dopants in spliced fibers is different (for example, it is equal to the diffusivity found in EDFA pump mixers) and tends to be complicated. The method of (EDF) splicing is related to intentionally expanding the mode field diameter (MFD) of a fiber with a smaller mode second diameter (Jew) by diffusing the raised ions beyond the core to match the second fiber. Of ^ Diameter (cut). The exponentially increasing ion diffusion has the dual effect of reducing the refractive index of the core layer. 85076 -6- 254 200407575 At the same time increasing the effective size of the core double effect. However, when we need to expand the mode field diameter (MFD) It is often difficult to control the expansion ratio that occurs. This dual effect of reducing the refractive index while increasing the core size makes it extremely difficult to stop the expansion of the mode field diameter (MFD) at the correct time. For example, when an amplifier Manufacturers may encounter problems when using bait-doped fiber (EDF) because the melting time used to sufficiently expand the mode field diameter is too short to provide sufficient mechanical strength. In addition, the short melting time makes the fusion machine The tolerance control becomes difficult, which leads to the problem of reconnectability. When the child welding machine changes due to the occurrence and accumulation of silicon on the electrode (changes in melting current, arc position and arc stability), When stability reaches equilibrium < shortened melting time has a greater impact, the matching problem becomes even more complicated. Many previous efforts Both are focused on trying to increase the expansion of a core (and therefore the mode field diameter (MFD)) rather than slow it down. An example reveals the use of fluorine diffusion to a -core to reduce the refractive index of the core relative to the cladding Design to increase the mode field diameter (MFD) expansion ratio. Another related example is described-a core dopant with an intentional diffusion index to increase the mode field diameter (D) to optimize bonding Method of loss. What is still needed is a conventional matching mode field diameter (D) of welding and a repeatable method to achieve this welding. [Inventive Content]
本發明係針對於一種光學熔接 芯與該包層之間一氟環之光纖。 ’其包括一具有介於該纖 本發明之熔接可使模場直 85076 200407575 徑（MFD)在擴大之同時，藉由減緩該模場直徑（MFD)之擴大 而獲得對過程之更高控制之益處。此外，因該模場直徑 (MFD)擴大比率之結果曲線可以預知且可藉由該含氟光纖之 化學組合物對該結果曲線加以控制，本發明允許用戶將所 需之熔融時間範圍與所需之模場直徑（MFD)擴大比率相匹 配。 根據本發明之熔接，其包括一具一第一模場直徑（MFD) 及一第一模場直徑（MFD)擴大比率之第一光纖。該熔接還包 括一具一第二模場直徑（MFD)及一第二模場直徑（MFD)擴大 比率之第二光纖，其中該第二模場直徑（MFD)小於該第一模 場直徑（MFD)。該第一光纖可具有一位於纖芯之中濃度小於 該第二光纖之指數升高摻雜劑或者該第一光纖可具有一位 於纖芯之中擴散率低於該第二光纖之摻雜劑。該第二光纖 之第二模場直徑（MFD)變化比率可由位於該區域中之氟含量 控制。 該第二光纖包括一纖芯、一沿半徑方向環繞於該纖芯之 包層及一位於該纖芯與包層之間具高濃度之氟區域。當該 區域中之氟含量南於纖芯或包層中之氟含量時5此情況被 定義為高濃度。在一特定具體實施例中，該區域中之最大 氟濃度為0.5至6 mol %之間。在熔接作業期間，該第一光纖 模場直徑（MFD)之擴大比率小於該第二光纖模場直徑（MFD) 之擴大比率。 該第二光纖之纖芯可捧辑、換銘及/或接錘]。該第二光纖 亦可包括至少一擴散障壁層。 85076 200407575 同樣’該第一光纖亦可包括一纖芯、一包層及一位於該 纖芯與包層之間具高濃度之氟區域，其中該第一光纖之模 場直徑（MFD)之變化比率可藉由氟含量及該指數升高之摻雜 劑之含量控制。 各種裝置均可獲益於一根據本發明之熔接。一包括該熔 接之寬帶光纖放大器係被涵蓋於此，其中該第一光纖及第 二光纖為不同波長提供放大作用。與此類似，一包括該溶 接之寬帶放大器，其中僅第二光纖可提供放大作用。該第 一光纖可為一泵浦鐳射混波器或一泵浦鐳射尾光纖。該等 裝置可成為傳訊系統之一部分。 一種對根據本發明之一第一及一第二光纖進行熔接之方 法，其包括經加熱提供一具有一第一模場直徑（MFD)及一第 一模場直徑（MFD)擴大比率之第一光纖及一具有一第二模場 直徑（MFD)及一第二模場直徑（MFD)擴大比率之第二光纖之 步驟。該第二模場直徑（MFD)小於該第一模場直徑（MFD)且 該第二模場直徑（MFD)擴大比率大於該第一模場直徑（MFD) 擴大比率。該第二光纖包括一纖芯、一沿半徑方向環繞於 纖芯之包層及一位於該纖芯與包層之間具高濃度之氟（F-) 環。該環中之氟（F)之平均濃度高於該纖芯中心或該包層外 緣中之氟之平均濃度。當與一無氟環之相似光纖進行比較 時，該氟環可減少該第二光纖之模場直徑（MFD)擴大比率。 接著，可於該第一光纖與第二光纖之模場直徑（MFD)相 匹配之同時，藉由向各個光纖之端面加熱及使二者緊密接 觸並加以光學校準而熔融此兩光纖。該第一及該第二光纖 85076 -9- 200407575 之模場直徑（MFD)在熔融步驟期間均可被監控，其中該加熱 步驟可被控制以獲得模場直徑（MFD)之匹配。或者，如該第 及忒第一光纖之模場直徑（MFD)擴大比率已為吾人所知， 可於一預定時間及預定溫度進行加熱，已知其為該第一及 第二模場直徑（MFD)擴大曲線之交叉處。 [實施方式] 圖1闡述了 一種根據本發明使用一熔接機5〇使一第一光纖 10與一第二光纖20熔接之方法。該方法包括提供具有一第 一模場直徑（MFD)和第一模場直徑（MFD)擴大比率之該第一 光纖ίο以及具有一第二模場直徑（MFD)和第二模場直徑 (MFD)擴大比率之該第二光纖2〇之步驟，其中該第二模場直 徑（MFD)小於㈣—模場直徑（MFD)且該第：模場直徑 (MFD)擴大比率大於該第一模場直徑（mfd)擴大比率。在一 具體實施例中，該第-光纖1G具有—位於纖芯之中濃度小 於該第二光纖20之指數升高摻雜劑。在另—替代實施例 中’該第-光纖U)具有-位於纖芯之中擴散率小於該第二 光纖20之指數升高摻雜劑。 安置於兩個電極 ’可於兩個電極 光纖10及20之端面12及22分別經校準並 3 0之間。在該等兩個電極間保持有一電壓 間產生一電旅3 2。 該電旅32可對該光纖端面12及22高溫加熱並將其溶化 接著，該等端面12及22在該第—及該第二光纖之模場直名 (MFD)進行匹配的同時被緊密接觸並加以光學校準。 在一具體實施例中，該第—光纖1〇為一習知尾光纖，你 85076 -10 - 200407575 如美國康寧公司（C〇rning)所生產之單模光纖_28 (SMF_28)。 該罘二光纖20包括一纖芯、一沿半徑方向環繞於該纖芯之 已層及一位於該纖芯與包層之間具高濃度之氟（F-)環，其中 位於該環中之氟（F)之平均濃度高於該纖芯中心或該包層外 、’彖中氟之平均濃度。當與一無氟（F-)環之相似光纖相比時， 孩氟（F-)環可減少該第二光纖之模場直徑（MFD)擴大比率。 在另一實施例中，該第一光纖及第二光纖（分別為1〇及2〇) 均包含一纖芯、一包層及一氟（F-)環，此氟環為一位於該纖 芯與包層之間橫跨邊界之具高濃度氟之區域。 該第一及該第二光纖之模場直徑（MFD)在熔融步驟期間 均可被監控且其曝光時間及/或溫度亦可被控制以獲得模場 直控（MFD)之匹。或|，若該第—及該第=光纖之模場直 位（MFD)擴大比率已為吾人所知，則該加熱步驟可包括應用 預先計算之曝光時間及/或溫度，以使該模場直徑（mfd)擴 大與相對之時間曲線相交。 圖2至圖9闡述了該第二光纖組合物之多種實例。圖2係對 一種根據本發明之光纖1〇〇之第一實施例之折射指數分佈描 述及截面示意圖進行了闡述。圖3至圖9係對根據本發明之 光纖之第二、第三、第四、第五及第六實施例之折射指數 分佈及截面示意圖分別進行了相似之闡述。使用末兩位數 相同之元件編號來標識相似元件。圖2至7所描述之折射指 數分佈之座標為與折射指數（n)及中心（r)之距離。該等座標 播單位且η座標未必會與r座標在零點處相交，因為該等附 圖之目的係為闡明該分佈形狀及指數關係而非特定之光學 85076 -11 - 200407575 物w之折射&數分佈。請注意該等附圖僅為闡述目的而使 用並非#曰根據實際所緣製之比例。熟悉此項技術者應 不難理解本發明所包括之各種其他設計。 圖2包括一種根據本發明對—具有—匹配包層凹陷環 (MCDR)設計纟光纖1〇〇之第一實施例所示之折射指數分佈 102及對應截面不意圖之描述。該物品⑽包括一具有一 半徑ΓΊ〈纖芯110、一具有一半徑以且環繞於該纖芯並與纖 芯同心之含氟區域或環12〇、具有一半徑〇且毗連於該環12〇 並與孩纖芯同心之一個或多個包層130及一環繞於該包層 130之基板$ 140。該包層13〇係一具高純度之玻璃層，其與 該纖芯110同心。該包層13〇之截面可為圓形、橢圓形、方 形、矩形或其他形狀。例如，在一種用於製造光纖之改良 化學氣體沈積（MCVD)光纖預製品中，該基板管14〇為一高 矽菅，其在形成内層、管壓縮及拉絲以前為中空。為獲得 所需 <光學及機械特性，該纖芯11〇、氟區域12〇及包層 之基礎成分通常亦為摻有不同化學製品之矽。在另一替代 實施例中，該包層130亦可包括多於一層之包層。 儘管圖2至9以示意圖闡述一光纖之截面指數分佈時，但 重要的是應瞭解通常該氟區域於拉絲期間會擴散至纖芯及/ 或包層從而產生一具高濃度之氟”區域”而非一可明確界定 之環。在本實施例及以下實施例中，重要的是應瞭解當該 氟已擴散時，就光學性能而論，功能上該含氟區域之特定 部分將成為該包層或纖芯之一部分。位於該含氟區域丨2〇中 之氟濃度大於位於該最内層之包層130及纖芯11〇中之氣濃 85076 -12- 200407575 度視^況，該含氟區域120亦可具有一與該包層指數相似 、、曰數在本發明中，該含氟區域120允許氟自所環繞之玻 璃中淨擴散至該纖芯而非自該纖芯擴散至所環繞之玻璃。 孩含氟區域120亦為”光狹窄”。該術語光狹窄可定義為此 鼠銥異寬度（氟環之外半徑減氟環之内半徑）約為該纖芯 之1/4直徑且該氟環之存在不會對最終光纖之波導特性產生 顯著消極影響。希望本發明物品的光學特性大體相同於一 才似汉汁之我氟環之物品（被稱做標準型）。具相似設計可 足義為光、截纖心之△( △為纖芯折射指數減去矽之折射指數） 之差異小於5% ,包層△之差異小於5%，纖芯直徑在以 内且包層直徑（減去該氟環層中之氟環差異寬度）在2%以内 之設計。 消極影響可定義$當與一具相似設計之無氣儲集層之標 準光纖相比較時，無法同時滿足本發明光纖之下列規格：基 P白模可於工作波長傳播、模場直徑為自45至6微米、工作 波長之3不損失<15dB/km，以及對一放大光纖而言，該（次 、=模）截止小於该放大器之泵浦波長（例如：根據用於該放大 器 < 泵浦波長，對餌而言，此為850至950奈米或<1480奈 米。）。 根據本發明之光纖易於接合且可被製造為具有所需之基 諧模截止、可接受之色散及模場直徑及低偏振模色散。本 發月所述之方法及物品亦可提供接近於該纖芯具低黏度之 玻璃，且可使背景衰減低於凹陷敗好之無氟環摻餌光纖中 《背景衰減。纟發明亦提供一種徑向修整氟分佈之方法。 85076 575 二车鲁'广擴散率遠大於稀土離子之擴散率時，本發明亦 、：施例於-氟氧化玻璃中之稀土離子中具有—非均衡 =?(:]如：可與氟化合之富含稀土區)，該分佈不會自- 氟氧化熔融物形成。此可導致該玻璃中具有更多不同 、項:稀土離子，其有助於光放大器光纖具有—更為寬闊 、^ &光4 °更寬《增益光譜對於密集波分複用（DWDM)光 放大器極為有利。 回到圖2，該含氟區120包括接近該纖芯11〇具高氟含量之 玻璃。位於孩含氟區域12〇中之氟濃度大於位於該纖芯 ，包層13G中之氟濃度。使職長色散X·射線分析（WDX)或 次級離子質譜分析（SIMS)，可以莫耳百分比對濃度進行量 測。孩含氟區120通常亦窄於該纖芯11〇或包層13〇且其設計 不致對該纖芯11〇或包層13〇之光功能產生干擾。 在圖2所示之该光學物品之實施例中，該光纖1 係一自 八有匹配指數包層設計（r3)之預製品拉出之單模光纖， 其具有一環繞於該纖芯（ri)之具微小凹陷指數（di)之高含氟 環（〇)。七為該環120及包層13〇之間之指數分佈差異。指數 分佈102為該初始預製品之一理想化截面指數分佈。通常希 望該氟環（儲集層）大體上不致對該光纖之波導特性產生影 響。例如，該基諧模截止仍可於15〇〇至165〇奈米區域内進 行單模操作且較之於一不含該氟儲集層區域之控制光纖， 該光纖之色散分佈實質上並未被改變。 該高濃度氟區域120具有一不同於該包層ι3〇之化學組合 物。然而’該儲集層區域120仍將與透射光相互作用且於光 85076 -14 - 200407575 學上將用作該包層130之一部分，特定言之係用作已發生氟 擴散之該最終光纖内之包層。 在圖2所述實施例之一特定方案中，該光纖具有該等特 性··（1)ΝΑ>0·2，較佳:>〇.25 ;⑺該模場直徑<6// m，較佳 為<5.5#m ; (3)於12〇〇奈米所量測之背景衰減<2〇dB/km， 較佳為<15dB/km，更佳為<i〇cJB/km ; (4)基諧模截止大於 1800奈米且（5)次級模截止<148〇奈米，較佳為<98〇奈米。 該等相同之光纖規格亦可用於圖3至9中所示之設計實施例 ⑩ 中 〇 圖3係根據本發明對一具有一匹配包層匹配環（mcmr)設 計之光纖200之第二實施例所示之該折射指數分佈2〇2及一 對應之截面示意圖所做之說明。在一具體實施例中，該光 學物品2〇〇係一單模光纖且具有一匹配指數包層23 〇(r3)及一 環繞於該纖芯210(ri)之具細小匹配指數之高濃度氟環 220(ι·2)。指數分佈202係該初始預製品之一理想化截面指數 分佈。 φ 圖4係根據本發明對一具有一凹陷包層下降環（dclr)設 计之光纖3 0 0之第三實施例所示之一初始預製品之理想化截 面之折射指數分佈3 02及一對應之截面示意圖所做之說明。 在一具體實施例中，該光纖300係單模光纖且具有一凹陷指 數（di)内包層330〇3)及外包層350設計，此設計具有一環繞 於該纖芯310(Γι)之具細小之深層凹陷指數（d2)之高濃度氟環 320〇2)。I為一 “井深”，即相對該外包層而言，用於該 内包層之凹陷指數之指數差異。相對該外包層而言，1為 85076 -15- 200407575 該環之折射指數之指數差異。 圖5係根據本發明對一具有一凹陷包層凹陷環⑴cdr)設 計之光纖400之第四實施例所示之一初始預製品之理想化截 面之折射指數分佈402及一對應之截面示意圖所做之說明。 在一具體實施例中，該光纖400係單模光纖且具有一凹陷内 包層430(0)及匹配指數外包層45〇(1>4)之設計，此設計具有 一裱繞於該纖芯41〇(ri)之具細小之凹陷指數（d2)(d2未圖示） 之南濃度氟環420(r2)。 圖6係根據本發明對一具有一匹配包層上升環（mcrr)設 計之光纖500之第五實施例所示之一初始預製品之理想化截 面折射指數分佈502及一對應之截面示意圖所做之說明。本 實施例所示之物品500係一單模光纖且具有一匹配指數包層 530(rs)之設計，其具有一大致位於該纖芯510/包層530介面 (Π)處之具細小上升指數之高濃度氟環520(Γ2)。該纖芯/包層 之介面可定義為該徑向位置，於此位置中，被量測之折射 指數等同於該等效步長指數（ESI)纖芯值與ESI包層值之平均 值。 圖7係根據本發明對一具有一凹陷包層上升環（DCrR)設 計之光纖600之第六實施例所示之一初始預製品之理想化截 面折射指數分佈602及一對應之截面示意圖所做之說明。該 實施例所示之光纖600係單模光纖且具有凹陷指數内包層 63 0〇3)及匹配指數外包層650〇4)，其具有一接近該纖芯/包 層介面610(ri)之具細小上升指數（dO之高濃度氟環62〇(r2)。 在圖8所述之一光纖700之另一實施例中，一擴散障壁層 85076 -16 - 200407575 760，例如一高矽環，其安置位置距離一芯層710比距離該 緊鄰氣環720更遠。較之於該包層中氟擴散率，該擴散障壁 層760通常係一可減小氟擴散率之高矽或其他物質。其目的 為減小擴散至该包層730之氟擴散，藉此使更多位於儲集層 720中 < 氟最終擴散至該纖芯71〇。該擴散障壁層76〇大體上 不會對該光纖之波導特性產生影響。 與所涉及之已將障壁層併入光纖以防止損失增大之雜質 擴散至接近纖芯之區域相比，本發明使用障壁層以防止氟 擴散出接近纖芯之區域，以增大纖芯中之氟含量。該擴散 障壁層760減少了 it離纖芯之氟擴散並可使更多之氟最終擴 散至該纖芯中。 一種障壁層之使用及本發明所述之該儲集層之概念可供 形成具有氟擴散區域之新穎實施例。在圖9所述之一替代實 施例800中，一第一障壁層860可被安置於該纖芯區域810中 或接近該區域，以靠近高氟濃度區域82〇之邊界為典型。該 第一障壁層860減少了擴散至纖芯81〇之内層部分之氟擴散 率 第一障壁層862可被安置於該包層區域830中或接近 孩區域，以減少穿過該包層之外層部分或介於兩包層間之 氟擴散率。 本發明 <氟0-)環摻餌光纖於熔接期間提高了對模場直徑 擴大之控制。在一具體實施例中，當對該光纖進行接合 時’用於將-具最佳之模場直徑與一具相對較大之模場直 徑之光纖匹配所需之時間比無含氟環環繞於該光纖纖芯之 可比較摻铒光纖設計之最佳接合所需時間約長2倍。假定不 85076 -17- 200407575 :、有σ氟％《光纖具有接合過快之熔融特徵’即，就機械 70正性及可重接性而言，該熔融時間如此短而降低所產生 之接合品質時’此特徵為—優勢。本發明所述之接合顯示 了當與通常於摻㈣纖放大器中所發現之尾光纖接合時之 更低且更為連貫之光損失。 接口損失之重要性應為摻餌光纖放大器（EDFA)專業人士 所瞭解。&同其對該泵浦及訊號所產生的影響一般，接合 損失會對料域放大器（EDFA)之雜訊絲、增益傾斜及 其他特性產生消極影響。當前之溶接技術可提供準確之纖 〜k準、該权準對接合損失模場直徑之不匹配起主要作用 (假定可以實現平端及垂直端分開，以及避免端面污染）。 可使用下列等式近似得出因模場不匹配F而產生之接合 損失： Γ (ω )=i〇 l〇g[(2 6； ιω 2)/(ω χ2 ω 22)]2 (ΐ) 其中ω ι及ω 2係被接合之兩光纖之模場半裡。 與使用普通摻有稀土光纖之接合相比，本發明具有損失 較低及可靠性較高之優勢。依據對等同於本發明光纖之光 纖（但無氟環）接合所進行之研究，環繞於纖芯之氟之存在具 有減緩模場直徑（MFD)擴大之效應。不希望被理論所束縛， 咸信此可藉由抵消纖芯外之指數升高摻雜劑之擴散而達 成。咸信當該等離子遭遇該氟時，其指數升高效應可被該 氟之指數降低效應抵消，導致對該纖芯波導尺寸之控制更 恆定。此將減少該模場直徑（MFD)之擴大比率（見以下實 例）。此外，接合損失結果顯示本發明光纖具有較低光損失 85076 -18- 200407575 及較高可重接性之優勢（見下表2)。 實例 圖10為一曲線圖，其展示了 一等同於本發明所述之光纖 但無氟環之光纖及所製造之具有一氟環之兩光纖熔接期間 之模場直徑特徵。在圖10中，模場直徑（MFD)被示作熔融時 間之一函數（二階擬合多項式），其顯示了本發明光纖模場直 徑（MFD)擴大之減小。 表1 光纖 二階多項式曲線擬合 方程式 (及 R2) 主導模場直徑擴大比 率條件 無氟(F-)環 y=0.1302x2+0.0495x- 0.0063 (R2=0.9996) 13.0% 標準氟(F-)環 y=0.0577x2+0.1124x- 0.0016 (R2=0.9999) 5.8% 超級氣(F-)i哀 y=0.0572x2+0.1074x- 0.0067 (R2=0.9988) 5.7% 上表1為一對圖10之曲線擬合資料之概述，其清楚展示了 本發明所述之光纖之模場直徑（MFD)擴大比率之減少。 圖11為一於熔接期間模場直徑（MFD)變化之標繪圖，其顯 示了模場直徑（MFD)匹配點（藉由表2所示之損失量測值解方 85076 -19- 200407575 程式1確定）。 因吾人已知熔融時間可藉由擴散直接影響模場直徑擴 大，所顯示之對大模場直徑光纖（單模光纖（SMF)-28)進行最 佳接合之熔融時間之差異與該氟環之併入有關。根據本發 明之具氟（F-)環之光纖及可與之比較之無氟環光纖之支援資 料顯示於表2中。 表2 摻餌光纖(EDF)-康寧單模光纖 SMF-28 氟環摻铒光 纖(EDF)-康寧 單模光纖 SMF-28 摻餌光纖 (EDF)-康寧 Flexcorl060 光纖 氟環摻_光 纖(EDF)-康 寧 Flexcorl060 光纖 平均接合損 失(dB) 0.235 0.217 0.122 0.061 標準偏差 _ 0.038 0.013 0.041 0.024 熔融時間 2(秒） 1.2 2.2 0.7 0.6 *所有其他參數均為常數；僅熔融時間2可調整以最佳化接 合損失。 上表2為對一無氟摻餌光纖（EDF)及用以對纖芯摻雜劑擴 散進行補償之含氟摻餌光纖（EDF)接合結果比較之概述。對 於無氟環之光纖而言，光纖之初始模場直徑（MFD)為5.17/zm; 對含氟環之光纖而言為5.15 /z m(所有資料均為在1550奈米 處）。 熟知此項技術者應理解本發明可用於需要進行模場直徑 (MFD)匹配之各種應用。儘管本發明之描述涉及具體較佳實 85076 -20- 200407575 施例’但本發明可以其他非#離本發明範圍之特定之形式 體現。因而，應理解本文所述之實施例僅為示範性實二 例’不應視為對本發明所述範圍之限制。根據本發明所述 範圍’可進行其他變動及修正。 [圖式簡單說明j 圖1為一根據本發明之熔接方法之圖示； 圖2為根據本發明對一具有一匹配包層凹陷環⑽⑽The present invention is directed to an optical fiber with a fluorine ring between an optical fusion core and the cladding. 'It includes a fusion splicing between the fiber of the present invention can make the mode field straight 85076 200407575 diameter (MFD) while expanding, by slowing the expansion of the mode field diameter (MFD) to obtain higher control of the process benefit. In addition, because the result curve of the mode field diameter (MFD) expansion ratio can be predicted and the result curve can be controlled by the chemical composition of the fluorine-containing optical fiber, the present invention allows the user to adjust the required melting time range to the required The mode field diameter (MFD) expansion ratio is matched. The fusion splicing according to the present invention includes a first optical fiber having a first mode field diameter (MFD) and a first mode field diameter (MFD) expansion ratio. The fusion splicing also includes a second optical fiber having a second mode field diameter (MFD) and a second mode field diameter (MFD) expansion ratio, wherein the second mode field diameter (MFD) is smaller than the first mode field diameter ( MFD). The first optical fiber may have a dopant having a lower concentration in the core than the second optical fiber or the first optical fiber may have a dopant having a lower diffusion rate in the core than the second optical fiber. . The second mode field diameter (MFD) change ratio of the second optical fiber can be controlled by the fluorine content in the region. The second optical fiber includes a core, a cladding surrounding the core in a radial direction, and a high-concentration fluorine region located between the core and the cladding. A high concentration is defined when the fluorine content in this area is south of the fluorine content in the core or cladding. In a specific embodiment, the maximum fluorine concentration in the region is between 0.5 and 6 mol%. During the splicing operation, the expansion ratio of the first fiber mode field diameter (MFD) is smaller than the expansion ratio of the second fiber mode field diameter (MFD). The core of the second optical fiber can be edited, changed name, and / or connected to the hammer]. The second optical fiber may also include at least one diffusion barrier layer. 85076 200407575 Similarly, the first optical fiber may also include a core, a cladding, and a high-concentration fluorine region between the core and the cladding, where the mode field diameter (MFD) of the first optical fiber changes The ratio can be controlled by the fluorine content and the dopant content of the index increasing. Various devices can benefit from a welding according to the invention. A broadband optical fiber amplifier including the fusion is included herein, wherein the first optical fiber and the second optical fiber provide amplification for different wavelengths. Similarly, one includes the fused broadband amplifier in which only the second optical fiber can provide amplification. The first optical fiber may be a pumped laser mixer or a pumped laser tail fiber. These devices can be part of a messaging system. A method of splicing a first and a second optical fiber according to the present invention, comprising heating to provide a first having a first mode field diameter (MFD) and a first mode field diameter (MFD) expansion ratio. Optical fiber and a second optical fiber having a second mode field diameter (MFD) and a second mode field diameter (MFD) expansion ratio. The second mode field diameter (MFD) is smaller than the first mode field diameter (MFD) and the second mode field diameter (MFD) expansion ratio is greater than the first mode field diameter (MFD) expansion ratio. The second optical fiber includes a core, a cladding surrounding the core in a radial direction, and a fluorine (F-) ring having a high concentration between the core and the cladding. The average concentration of fluorine (F) in the ring is higher than the average concentration of fluorine in the core center or the outer edge of the cladding. When compared to a similar fiber without a fluorine ring, the fluorine ring can reduce the mode field diameter (MFD) expansion ratio of the second fiber. Then, while matching the mode field diameter (MFD) of the first optical fiber and the second optical fiber, the two optical fibers can be fused by heating the end faces of the respective optical fibers, bringing them into close contact, and performing optical alignment. The mode field diameter (MFD) of the first and the second optical fibers 85076 -9- 200407575 can be monitored during the melting step, wherein the heating step can be controlled to obtain a matching mode field diameter (MFD). Alternatively, if the enlargement ratio of the mode field diameter (MFD) of the first and second optical fibers is known to us, it can be heated at a predetermined time and a predetermined temperature, which is known as the first and second mode field diameters ( MFD) Enlarge the intersection of the curves. [Embodiment] Fig. 1 illustrates a method for splicing a first optical fiber 10 and a second optical fiber 20 using a splicer 50 according to the present invention. The method includes providing the first optical fiber having a first mode field diameter (MFD) and a first mode field diameter (MFD) enlargement ratio, and having a second mode field diameter (MFD) and a second mode field diameter (MFD). A step of expanding the second optical fiber 20, wherein the second mode field diameter (MFD) is smaller than ㈣-mode field diameter (MFD) and the second: mode field diameter (MFD) expansion ratio is greater than the first mode field Diameter (mfd) enlargement ratio. In a specific embodiment, the first optical fiber 1G has an exponentially increasing dopant that is located in the core of the optical fiber 1G at a concentration lower than that of the second optical fiber 20. In another alternative embodiment, the 'the first optical fiber U) has an exponentially increasing dopant having a diffusivity lower than that of the second optical fiber 20 in the core. Placed on the two electrodes ′ may be aligned on the two electrodes and the end faces 12 and 22 of the optical fibers 10 and 20 are between 30 and 30, respectively. A voltage is maintained between the two electrodes to generate an electrical trip 3 2. The electrical brigade 32 can heat and melt the end faces 12 and 22 of the optical fiber at high temperature. Then, the end faces 12 and 22 are closely contacted while matching the mode field name (MFD) of the first and second optical fibers. And optical calibration. In a specific embodiment, the first optical fiber 10 is a conventional pigtail fiber. You 85076 -10-200407575 is a single-mode optical fiber 28 (SMF_28) produced by Corning Corporation. The second optical fiber 20 includes a core, a layer that surrounds the core in a radial direction, and a fluorine (F-) ring with a high concentration between the core and the cladding. The average concentration of fluorine (F) is higher than the average concentration of fluorine in the center of the core or outside the cladding. When compared to a similar fiber with a fluorine-free (F-) ring, a child fluorine (F-) ring can reduce the mode field diameter (MFD) expansion ratio of the second fiber. In another embodiment, the first optical fiber and the second optical fiber (10 and 20 respectively) each include a core, a cladding and a fluorine (F-) ring, and the fluorine ring is a fiber located in the fiber A region of high fluorine concentration across the boundary between the core and the cladding. The mode field diameter (MFD) of the first and the second fibers can be monitored during the fusing step and their exposure time and / or temperature can be controlled to obtain a mode field direct control (MFD) match. Or |, if the—and the —mode field alignment (MFD) expansion ratio of the fiber is already known to me, the heating step may include applying a pre-calculated exposure time and / or temperature to make the mode field The enlarged diameter (mfd) intersects the relative time curve. Figures 2 to 9 illustrate various examples of the second optical fiber composition. Fig. 2 illustrates a refractive index distribution description and a schematic cross-sectional view of a first embodiment of an optical fiber 100 according to the present invention. Figures 3 to 9 are similar descriptions of the refractive index distributions and cross-sectional views of the second, third, fourth, fifth, and sixth embodiments of the optical fiber according to the present invention, respectively. Use the same last two digits to identify similar components. The coordinates of the refractive index distributions described in Figures 2 to 7 are the distances from the refractive index (n) and the center (r). These coordinate broadcasting units and the η coordinate may not necessarily intersect with the r coordinate at zero, because the purpose of these drawings is to clarify the distribution shape and exponential relationship rather than the specific optical 85076 -11-200407575 refraction & Number distribution. Please note that these drawings are for illustrative purposes only and are not proportions based on actual conditions. Those skilled in the art should readily understand the various other designs included in the present invention. FIG. 2 includes a description of the refractive index distribution 102 and the corresponding cross section shown in the first embodiment of a paired-with-cladding recessed ring (MCDR) design of the optical fiber 100 according to the present invention. The article ⑽ includes a core 110 having a radius ΓΊ <, a fluorine-containing region or ring 120 having a radius and surrounding the core and concentric with the core 120, having a radius 0 and adjoining the ring 12. And one or more cladding layers 130 concentric with the child fiber core and a substrate $ 140 surrounding the cladding layer 130. The cladding layer 13 is a high-purity glass layer which is concentric with the core 110. The cross section of the cladding layer 13 can be circular, oval, square, rectangular or other shapes. For example, in a modified chemical gas deposition (MCVD) optical fiber preform used to manufacture optical fibers, the substrate tube 14 is a high silicon halide that is hollow before forming the inner layer, compressing and drawing the tube. In order to obtain the required < optical and mechanical properties, the basic component of the core 11, the fluorine region 12 and the cladding is usually silicon doped with different chemicals. In another alternative embodiment, the cladding layer 130 may include more than one cladding layer. Although Figures 2 to 9 illustrate the exponential distribution of the cross section of an optical fiber in a schematic diagram, it is important to understand that the fluorine region usually diffuses to the core and / or cladding during the drawing process to produce a high concentration of fluorine "region" Rather than a clearly definable ring. In this embodiment and the following examples, it is important to understand that when the fluorine has diffused, as far as optical performance is concerned, a specific portion of the fluorine-containing region will functionally become a part of the cladding or core. The fluorine concentration in the fluorine-containing region 20 is greater than the gas concentration in the innermost cladding layer 130 and the core 11850. 85076 -12- 200407575 degrees Depending on the situation, the fluorine-containing region 120 may also have an The cladding index is similar. In the present invention, the fluorine-containing region 120 allows net diffusion of fluorine from the surrounding glass to the core rather than from the core to the surrounding glass. The child fluorine-containing area 120 is also "light narrow". The term optical narrowness can be defined as the rat's iridium heterogeneous width (outer radius of the fluorine ring and inner radius of the fluorine ring) is about 1/4 of the diameter of the core and the presence of the fluorine ring will not produce waveguide characteristics of the final fiber Significant negative impact. It is hoped that the optical characteristics of the article of the present invention are substantially the same as those of the fluorene ring (known as the standard type) that looks like Han juice. A similar design is enough to mean that the difference between △ (the core refractive index minus the refractive index of silicon) of the core of the light and the fiber is less than 5%, the difference of the cladding △ is less than 5%, the core diameter is within and the The layer diameter (minus the fluorine ring difference width in the fluorine ring layer) is designed within 2%. Negative effects can be defined. When compared with a standard optical fiber with a similar design of an airless reservoir, the following specifications of the optical fiber of the present invention cannot be met at the same time: the basic P white mode can propagate at the working wavelength and the mode field diameter is from 45 Up to 6 microns, no loss of 3 working wavelengths < 15dB / km, and for an amplified fiber, the (sub, = mode) cut-off is less than the pump wavelength of the amplifier (eg: according to the pump used for the amplifier < The wavelength is 850 to 950 nanometers or <1480 nanometers for bait.). The optical fiber according to the present invention is easy to splice and can be manufactured to have the required fundamental mode cutoff, acceptable dispersion and mode field diameter, and low polarization mode dispersion. The methods and articles described in this publication can also provide low-viscosity glass close to the fiber core, and can make the background attenuation lower than the background attenuation in the fluorinated ring-free bait-doped fiber with a good recess. The invention also provides a method for radially modifying the fluorine distribution. 85076 575 Erchelu's wide diffusivity is far greater than that of rare earth ions. The present invention also has: non-equilibrium =? Rare earth-rich regions), this distribution does not form from -fluorine oxidation melts. This can lead to more different items in the glass: rare earth ions, which help optical amplifier fibers have-wider, ^ & light 4 ° wider, gain spectrum for dense wavelength division multiplexed (DWDM) light The amplifier is extremely advantageous. Returning to FIG. 2, the fluorine-containing region 120 includes a glass with a high fluorine content close to the core 11. The fluorine concentration in the fluorine-containing region 120 is greater than the fluorine concentration in the core 13G. Dispersive X-ray analysis (WDX) or secondary ion mass spectrometry (SIMS) can be used to measure the concentration in mole percentage. The fluorine-containing region 120 is also generally narrower than the core 11 or the cladding 13 and is designed so as not to interfere with the optical function of the core 11 or the cladding 13. In the embodiment of the optical article shown in FIG. 2, the optical fiber 1 is a single-mode optical fiber drawn from a preform having a matching index cladding design (r3), which has a core (ri ) Has a high fluorine-containing ring (0) with a slight depression index (di). Seven is the difference in the exponential distribution between the ring 120 and the cladding 130. The index distribution 102 is an idealized cross-section index distribution of one of the initial preforms. It is generally desirable that the fluorine ring (reservoir) does not substantially affect the waveguide characteristics of the fiber. For example, the fundamental harmonic mode can still perform single-mode operation in the region of 1500 to 1650 nanometers. Compared to a control fiber that does not contain the fluorine reservoir region, the dispersion distribution of the fiber is substantially unchanged. Was changed. The high-concentration fluorine region 120 has a chemical composition different from the cladding layer 30. However, 'the reservoir region 120 will still interact with the transmitted light and will be used as part of the cladding 130 in the light 85076 -14-200407575, in particular to be used in the final fiber where fluorine diffusion has occurred Of the cladding. In a specific solution of the embodiment described in FIG. 2, the optical fiber has the following characteristics: (1) NA > 0.2, preferably: >0.25; ⑺ the mode field diameter < 6 // m ≪ 5.5 # m; (3) Background attenuation measured at 1200nm < 20dB / km, preferably < 15dB / km, more preferably < ioccJB (4) The fundamental mode cutoff is greater than 1800 nm and (5) the secondary mode cutoff is < 148 ° nm, preferably < 98 ° nm. These same optical fiber specifications can also be used in the design embodiments shown in FIGS. 3 to 9. FIG. 3 is a second embodiment of an optical fiber 200 having a matching cladding matching ring (mcmr) design according to the present invention. The refractive index distribution 202 shown in the figure and a corresponding cross-sectional schematic are explained. In a specific embodiment, the optical article 200 is a single-mode optical fiber and has a matching index cladding 23 (r3) and a high-concentration fluorine with a small matching index surrounding the core 210 (ri). Ring 220 (ι · 2). The exponential distribution 202 is an idealized cross-sectional exponential distribution of one of the initial preforms. Fig. 4 shows the refractive index distribution of an idealized cross section of an initial preform shown in the third embodiment of an optical fiber 3 0 0 with a recessed cladding descending ring (dclr) according to the present invention. Corresponding cross-section schematic description. In a specific embodiment, the optical fiber 300 is a single-mode optical fiber and has a dimple (di) inner cladding 3303) and an outer cladding 350 design. The design has a small and fine shape surrounding the core 310 (Γι). The deep depression index (d2) of the high-concentration fluorine ring 3202). I is a “well depth”, that is, the index difference of the depression index for the inner cladding layer relative to the outer cladding layer. Relative to the outer layer, 1 is the index difference of the refractive index of the ring of 85076 -15- 200407575. FIG. 5 is a refractive index distribution 402 of an idealized cross section of an initial preform shown in a fourth embodiment of a fiber 400 having a recessed cladding (cdr) design in accordance with the present invention and a corresponding cross-sectional schematic diagram Description. In a specific embodiment, the optical fiber 400 is a single-mode optical fiber and has a design of a recessed inner cladding 430 (0) and a matching index outer layer 45〇 (1 > 4). This design has a frame mounted on the core 41 〇 (ri) with a small depression index (d2) (d2 is not shown) of the south concentration fluorine ring 420 (r2). FIG. 6 is an idealized cross-section refractive index distribution 502 and a corresponding cross-sectional schematic diagram of an initial preform shown in a fifth embodiment of an optical fiber 500 having a matching clad rising ring (mcrr) design according to the present invention. Description. The article 500 shown in this embodiment is a single-mode optical fiber and has a matching index cladding 530 (rs) design, which has a small rising index located approximately at the core 510 / cladding 530 interface (Π). High concentration fluorine ring 520 (Γ2). The core / cladding interface can be defined as the radial position in which the measured refractive index is equal to the average of the equivalent step index (ESI) core value and the ESI cladding value. FIG. 7 is an idealized cross-section refractive index distribution 602 and a corresponding cross-sectional schematic diagram of an initial preform shown in a sixth embodiment of an optical fiber 600 having a recessed cladding rising ring (DCrR) according to the present invention. Description. The optical fiber 600 shown in this embodiment is a single-mode optical fiber with a recessed index inner cladding 63 0003) and a matching index outer cladding 6504), which has a tool close to the core / clad interface 610 (ri). Fine rising index (dO high concentration fluorine ring 620 (r2). In another embodiment of the optical fiber 700 described in FIG. 8, a diffusion barrier layer 85076 -16-200407575 760, such as a high silicon ring, which The placement position is farther from a core layer 710 than the immediate gas ring 720. Compared to the fluorine diffusion rate in the cladding, the diffusion barrier layer 760 is usually a high silicon or other substance that can reduce the fluorine diffusion rate. The purpose is to reduce the diffusion of fluorine to the cladding 730, thereby allowing more fluorine located in the reservoir 720 to eventually diffuse to the core 71. The diffusion barrier layer 76 will not substantially affect the optical fiber. The waveguide characteristics have an effect. Compared with the involved barrier layer which has been incorporated into the optical fiber to prevent impurities with increased loss from diffusing to the area near the core, the present invention uses a barrier layer to prevent fluorine from diffusing out of the area near the core, To increase the fluorine content in the core. The diffusion barrier layer 760 reduces i The diffusion of fluorine from the core can allow more fluorine to eventually diffuse into the core. The use of a barrier layer and the concept of the reservoir described in the present invention can be used to form novel embodiments with fluorine diffusion regions In an alternative embodiment 800 described in FIG. 9, a first barrier layer 860 may be disposed in or near the core region 810, and a boundary near the high fluorine concentration region 82 is typical. A barrier layer 860 reduces the diffusivity of fluorine to the inner layer portion of the core 81. The first barrier layer 862 may be placed in the cladding area 830 or near the child area to reduce the penetration of the outer layer portion of the cladding or The fluorine diffusion rate between the two cladding layers. The present invention < fluorine 0-) ring bait-doped fiber improves the control of mode field diameter expansion during splicing. In a specific embodiment, when the fiber is spliced, the time required to match the fiber with an optimal mode field diameter to a fiber with a relatively large mode field diameter surrounds the fiber without the fluorine-containing ring. The optimal splicing time of the comparable erbium-doped fiber design of this fiber core is approximately 2 times longer. Assumes not 85076 -17- 200407575: There is σ fluorine% "The optical fiber has a fusion characteristic of too fast splicing ', that is, in terms of mechanical 70 positiveness and reconnectability, the melting time is so short that the quality of the splicing is reduced. This feature is-advantage. The splicing described in the present invention shows a lower and more consistent light loss when splicing with tailed fibers commonly found in erbium-doped fiber amplifiers. The importance of interface loss should be understood by EDFA professionals. & As with its effects on the pump and signal, joint loss will negatively affect the noise wire, gain tilt, and other characteristics of the material domain amplifier (EDFA). The current fusion technology can provide accurate fiber to k-standards, and this standard plays a major role in the mismatch of the joint loss mode field diameter (assuming that the flat and vertical ends can be separated, and the end surface pollution is avoided). The following equation can be used to approximate the joint loss due to mode field mismatch F: Γ (ω) = i〇l0g [(2 6; ιω 2) / (ω χ2 ω 22)] 2 (ΐ) Among them, ω ι and ω 2 are the mode fields of the two optical fibers that are spliced. Compared with the splicing using ordinary rare earth-doped optical fibers, the present invention has the advantages of lower loss and higher reliability. Based on research conducted on optical fiber (but without fluorine ring) splices equivalent to the optical fiber of the present invention, the presence of fluorine around the core has the effect of slowing the expansion of the mode field diameter (MFD). Without wishing to be bound by theory, I believe this can be achieved by offsetting the exponentially increasing dopant diffusion outside the core. It is believed that when the plasma encounters the fluorine, its exponential increase effect can be offset by the exponential decrease effect of the fluorine, resulting in more constant control of the core waveguide size. This will reduce the enlargement ratio of the mode field diameter (MFD) (see example below). In addition, the splice loss results show that the optical fiber of the present invention has the advantages of lower optical loss 85076 -18-200407575 and higher reconnectability (see Table 2 below). Example FIG. 10 is a graph showing a mode field diameter characteristic of an optical fiber equivalent to the optical fiber of the present invention but without a fluorine ring and the manufactured two optical fibers having a fluorine ring during splicing. In Fig. 10, the mode field diameter (MFD) is shown as a function of the melting time (second-order fitting polynomial), which shows a reduction in the expansion of the mode field diameter (MFD) of the optical fiber of the present invention. Table 1 Optical fiber second-order polynomial curve fitting equations (and R2) Dominant mode field diameter expansion ratio condition Fluorine-free (F-) ring y = 0.1302x2 + 0.0495x- 0.0063 (R2 = 0.9996) 13.0% standard fluorine (F-) ring y = 0.0577x2 + 0.1124x- 0.0016 (R2 = 0.9999) 5.8% Super Gas (F-) i y = 0.0572x2 + 0.1074x- 0.0067 (R2 = 0.9988) 5.7% The above table 1 is a pair of curves in Figure 10 An overview of the fitting data, which clearly shows the reduction in the expansion ratio of the mode field diameter (MFD) of the optical fiber according to the present invention. Figure 11 is a plot of the change in mode field diameter (MFD) during welding, showing the mode field diameter (MFD) matching points (using the loss measurement values shown in Table 2 to solve the solution 85076 -19- 200407575 Equation 1 determine). Since we know that the melting time can directly affect the expansion of the mode field diameter by diffusion, the difference between the melting time of the best splicing of a large mode field diameter fiber (single mode fiber (SMF) -28) and the fluorine ring is shown. Incorporate related. The supporting information of the fluorine (F-) ring optical fiber according to the present invention and the comparable fluorine-free ring optical fiber are shown in Table 2. Table 2 Erbium-doped fiber (EDF)-Corning single-mode fiber SMF-28 Erbium-doped fiber (EDF)-Corning single-mode fiber SMF-28 Erbium-doped fiber (EDF)-Corning Flexcorl060 Fluoro-ring doped fiber (EDF) -Corning Flexcorl060 fiber average splice loss (dB) 0.235 0.217 0.122 0.061 standard deviation_ 0.038 0.013 0.041 0.024 Melting time 2 (seconds) 1.2 2.2 0.7 0.6 * All other parameters are constant; only the melting time 2 can be adjusted to optimize splicing loss. Table 2 above is a summary of the comparison of the results of splicing of a fluorine-free bait-doped fiber (EDF) and a fluorine-containing bait-doped fiber (EDF) used to compensate the core dopant dispersion. For fluorine-free fiber, the initial mode field diameter (MFD) of the fiber is 5.17 / zm; for fluorine-containing fiber, it is 5.15 / z m (all data are at 1550 nm). Those skilled in the art will understand that the present invention can be used in a variety of applications requiring mode field diameter (MFD) matching. Although the description of the present invention relates to specific preferred embodiments 85076 -20- 200407575 embodiments, the present invention may be embodied in other specific forms without departing from the scope of the invention. Therefore, it should be understood that the embodiments described herein are only exemplary examples' and should not be considered as limiting the scope of the present invention. Other changes and modifications can be made in accordance with the scope of the present invention. [Schematic description j Figure 1 is a diagram of a welding method according to the present invention; Figure 2 is a diagram of a recessed ring with a matching cladding according to the present invention.
=計之光纖之第-實施例之折射指數分佈及—對應截面示 意圖之描述； 圖3為一根據本發明科^^目七 、、 心月對具有一匹配包層匹配環（MCMR) 设计之光纖之第-會说办丨邮-、 實她例所7折射指數分佈及一對應截 面示意圖之描述； 圖4為一根據本發明豐一 、、 λ月對 八有一凹陷包層下降環（DCLR) 設計之光纖之第=香& 一、 一 實施例所不〈折射指數分佈及一對應截 面示意圖之描述； 圖5為一根據本發明斟一 ^ n 具有一凹陷包層凹陷環（DCDR) 設計之光纖之第四眘说加邮一、 實施例所tf <折射指數分佈及一對應截 面不思圖之描述； 圖6為一根據本菸 發月對具有一匹配包層上升環（MCRR) 設計之光纖凌筮τ成、 一 > 五實施例所示之折射指數分佈及一對應截 面示思圖之描述； 圖 7 為—k is 4« ^ 本發明對一具有一凹陷包層上升環（DCRR) 一、'纖之第六實施例所示之折射指數分佈及一對應截 面示意圖之描述； 85076 -21 - 200407575 圖8為一根據本發 ^ # # π ^ 具有一 Ρ早壁層設計之光纖之第+ 貫-例所示之截面示意圖之描述； 弟七 ，為才艮據本發明對一具有雙重障壁層設 八貫施例所示之截面示意圖之描述; 〜 圖ίο為：種不同光纖之模場直徑⑽够變化與熔 對比之曲線圖； 了間 :表符=直徑~時間對…線圖 10 第一光纖 12 之端面 20 弟一光纖 22 20之端面 30 電極 32 電弧 50 熔接機 100,200,300,400,500,600,700 光纖 102,202,302,402,502,602 折射指數分佈 110,210,310,410,510,710,810 纖芯 120 含氟區域或環 130,730,830 包層 140 基板管 220 匹配指數含氟區域或環 230,330,530 匹配指數包層 320 匹配指數含氟區域或環= The refractive index distribution of the first embodiment of the optical fiber and the description of the corresponding cross-sectional schematic diagram; Figure 3 is a design of a matching cladding matching ring (MCMR) pair according to the subject of the invention. The description of the refractive index distribution and a corresponding cross-sectional schematic diagram of the 7th optical fiber of the fiber-optic post, and real examples; Figure 4 is a descent ring (DCLR) The design of the optical fiber is as follows: 1. A description of the refractive index distribution and a corresponding cross-sectional schematic diagram according to an embodiment; FIG. 5 is a diagram showing a recessed cladding recessed ring (DCDR) according to the present invention. The fourth cautionary note of the designed optical fiber Canada Post 1. The description of the tf < refractive index distribution and a corresponding cross-section diagram in the embodiment; Figure 6 is a pair of cladding rising rings (MCRR ) The design of the optical fiber is shown in Fig. 5. The refractive index distribution shown in the fifth embodiment and the description of a corresponding cross-sectional diagram; Figure 7 is-k is 4 «^ The present invention rises to a cladding with a recess Ring (DCRR) First, as shown in the sixth embodiment of the fiber Description of the refractive index distribution and a corresponding cross-sectional schematic diagram; 85076 -21-200407575 Figure 8 is a cross-sectional schematic diagram shown in the + thru-th example of an optical fiber with a P early wall layer design according to the present invention ^ # # π ^ Description; Di Qi, according to the present invention is a description of a schematic cross-sectional view of an embodiment with double barrier layers with eight passes; ~ Figure ο is: the curve of the mode field diameter of a different optical fiber is sufficient to compare with the melting contrast curve Figure: Indicator: Diameter = time pair ... Line diagram 10 The first end face of the first fiber 12 20 the first end of the fiber 22 20 the end face 30 of the electrode 32 arc 50 fusion machine 100, 200, 300, 400, 500, 600, 700 optical fiber 102, 202, 302, 402, 502, 602 Refractive index distribution 110, 210, 310, 410, 510, 710, 810 Core 120 fluorinated area OR ring 130,730,830 cladding 140 substrate tube 220 matching index fluorine-containing region or ring 230,330,530 matching index cladding 320 matching index fluorine-containing region or ring
85076 -22- 200407575 350 外包層 420 深層凹陷指數含氟區域或環 430,630 凹陷指數内包層 450,650 匹配指數外包層 520,620 上升指數含氟區域或環 610 纖芯/包層介面 720 氟區域或環 760 擴散障壁層 820 含氟區域或環 860 第一障壁層 862 第二障壁層 ri, r2, r3, r4 半徑 di 凹陷指數 d2 上升指數 n 折射指數 85076 -23-85076 -22- 200407575 350 Outer layer 420 Deep depression index fluorine-containing area or ring 430,630 Sag index inner cladding 450,650 Matching index outer layer 520,620 Rising index fluorine-containing area or ring 610 Core / cladding interface 720 Fluorine area or ring 760 Diffusion barrier Layer 820 fluorinated region or ring 860 first barrier layer 862 second barrier layer ri, r2, r3, r4 radius di depression index d2 rising index n refractive index 85076 -23-