1286229 玖、發明說明： (一） 發明所屬之技術領域 本發明係有關於連接兩條光纖之構造。 (二） 先前技術 在以往，連接兩條光纖之構造中，大致分爲兩種構造而 爲人所知。 一種，係將兩條光纖之前端彼此在核心聚集於相同軸心 之狀態下進行融合之構造。另一種，係將兩條光纖以不融 合而分別將各核心之前端彼此接觸之狀態進行連接之構 造。後者更具有具體之構造，例如特公平4-693 69號公報 所記載般，由分別固定兩條光纖之前端部之兩個套圈、各 套環係在各光纖之核心前端互相相向之狀態穿插過共通之 套筒管、以及將各套圈係維持在前述兩條光纖之核心前端 互相接觸狀態之維持機構所構成連接器，廣爲人知。 〔特許文獻〕特公平4-69369號公報 (發明所欲解決之問題） 但是，在波長短、特別是處理由G a N類半導體雷射所 發射出之波長爲3 5 0〜5〇Onm程度之光之裝置方面，得知於 光學元件之光密度高之光通過端面，會堆積起汽化之有機 物質以及與雷射光作光化學反應所產生之物質，亦即產生 所謂之集塵效果。如此當光學元件之光通過端面上附著有 污染物質時，產生爲了獲得既定之光輸出所必要之半導體 雷射驅動電流會提高，雷射光之傳遞損失會增大之問題。 又，得知此集麈效果中，碳化物爲其起因，以及矽氧烷爲 一 5- 1286229 其起因。 即使在前述光纖中，在前述傳遞之短波長之光之場合， 在核心之入射端面或是射出端面上會產生集麈效果。因此， 即使在兩條光纖之連接部位，核心之端面彼此遍佈全面完 全不接觸，若是形成該端面之一部與外部氣體接觸之狀態 的話，會產生集塵效果。 在如前述般將兩條光纖作融合之連接構造方面，一般， 由於核心之端面全面彼此完全地接合，所以不會產生集塵 效果。但是，適用於此構造，必須要有專用高價之融合機， 除了作業繁雜之外，亦存在因作業現場而無法準備該融合 機之問題。又，在此連接構造之場合中，要將曾經連接過 之光纖重新連接的話，必須要接受切斷融合部再一次進行 融合作業之繁複。 另一方面，即使在不將兩條光纖融合，各核心之前端 彼此接觸狀態下進行連接之構造中，核心之端面全面完全 接觸的話不會產生集塵效果。在單一模式光纖之場合中， 由於係如核心全體進行接觸般推壓光纖進行連接，不易產 生集塵效果。但是，在多種模式光纖般之核心口徑大之光 纖之場合，使核心端面彼此遍佈全面地接觸係爲困難，因 此會形成核心端面之一部與外部氣體接觸之狀態，容易造 成集塵效果。 本發明係有鑑於前述問題，以提供可防止在互相連接之 光纖前端產生集塵效果，並且不需要龐大融合機能夠簡便 地將兩條光纖連接之構造爲目的。 一 6 一 1286229 又，除此之外，本發明係以提供將兩條光纖一旦連接之 後，能夠簡單地重新連接之光纖之連接構造爲目的。 (三）發明內容 (解決問題之方法） 本發明之第1光纖之連接構造，將兩條光纖不需要融 合，在各核心之前端彼此接觸之狀態下進行連接，其特徵 爲包含核心前端之光纖之前端部係收容於密閉空間內，該 密閉光間係封入有鈍性氣體，或是對於光纖所傳遞之光而 言係透明不會因該光而分解之液體。 本發明之第2光纖之連接構造，與前述同樣地，將兩條 光纖不需要融合，在各核心之前端彼此接觸之狀態下進行 連接，其特徵爲：包含核心前端之光纖之前端部係收容於 連接於流體循環裝置之流體供應口以及流體排出口之容器 內，該容器內充滿有循環之鈍性氣體，或是對於光纖所傳 遞之光而言係透明不會因該光而分解之液體。 又，在本發明之第1以及第2光纖之連接構造中，所謂 的將兩條光纖進行連接，並不單指單一之光纖彼此進行連 接之場合，亦包含光纖陣列彼此又或者是光纖束彼此進行 連接之物件方面光纖陣列彼此又或者是光纖束中之光纖一 對一使其對應之場合。 又，在此所謂的鈍性氣體，乃是指對於構成光纖或是連 接器等之材料爲不具活潑性之氣體，具體而言，可列舉乾 燥之氮氣、氬氣等之稀有氣體。 又，在第1光纖之連接構造方面前述密閉空間內封入鈍 一 7- 1286229 性氣體之場合，以及在第2光纖之連接構造方面前述容器 內充滿鈍性氣體之場合，以該鈍性氣體混入有濃度1 ppm以 上之氧氣、鹵素氣體以及/又或者是鹵素化合物之氣體爲 佳。也就是說，作爲封裝之內部氣體環境，則是以（1)鈍性 氣體與濃度Ippm以上之氧氣混合之氣體，（2)至少與鈍性 氣體與鹵素氣體以及鹵素化合物氣體中任何一方之氣體作 混合之氣體，（3)鈍性氣體與lppm以上之氧氣、鹵素氣體 以及鹵素化合物之氣體至少與任何一方之氣體作混合之氣 體爲佳。 又，前述鹵素氣體以及鹵素化合物，以含有氟原子爲佳。 又，鹵素化合物氣體以由碳、氮、硫磺以及氙等之氟化物 以及碳、氮、硫磺以及氙等之氯化物所構成之族群中至少 選擇一種爲佳。 所謂鹵素氣體，係指氯氣Cl2、氟氣F2等鹵素氣體，鹵 素化合物之氣體，係指含有氯C1、溴Br、碘I、氟F等鹵 素原子之氣體狀化合物。 鹵素化合物氣體中，可列舉 CF3C1、CF2C12、CFC13、 CF3Br、CC14、CCl4-02、C2F4C12、Cl-H2、CF3Br、PC13、CF4、 SF6、NF3、XeF2、C3F8、CHF3等，以氟或是氯與碳元素C、 氮N、硫S、氙Xe之化合物爲佳，特別是以含有氟原子之 氣體爲佳。 又，施加於光纖之射出端面以及入射端面上之包覆之最 表面層，以對於鹵素氣體以及鹵素化合物爲不活潑性材料 加以構成爲佳。該不活潑性材料，以銦、鎵、鋁、鈦、釔 一 8- 1286229 之各種氧化物以及銦、鎵、鋁、鈦、釔之各種氮化物所構 成之族群中至少選擇一種爲佳。 又’使用於前述第1與第2光纖之連接構造之鈍性氣體 或是液體’以未含有矽類有機物之物件爲佳。 此外’本發明之第3光纖之連接構造，與前述相同地將 兩條光纖不需要融合，在各核心之前端彼此接觸之狀態下 進行連接’其特徵爲：包含核心前端之光纖之前端部係藉 由以熔融狀態供應到該前端部之後進行凝固，對於光纖所 傳遞之光而言係透明不會因該光而分解之固體與外部加以 隔絕。 在此，前述之固體，可使用低熔點玻璃等爲佳。 又’如前述般不將兩條光纖融合而加以連接之具體構造 中，例如可使用，兩條光纖之前端部分別固定於各套圈上， 套圈係在各光纖之核心前端互相相向之狀態穿插過共通之 套筒管，各套圈維持在前述兩條光纖之核心前端互相接觸 之狀態之構造。 又，本發明之光纖之連接構造中，兩條光纖傳遞之光之 波長以3 5 0〜5 OOnm之範圍之場合爲佳。 (發明之效果） 在本發明之第1光纖之連接機構，由於收容著光纖之前 端部之密閉空間內，封入有鈍性氣體，或是對於光纖所傳 遞之光而言係透明不會因該光而分解之液體，如果核心之 前端遍佈全面爲未接觸之場合，該未接觸之部分會成爲與 鈍性氣體以及液體接觸之狀態。因此，引起前述之集塵效 -9 一 1286229 果之有機物等與光纖傳遞之雷射光不會產生光化學反應， 能夠抑制在光纖前端所產生之集塵效果。 又，在本發明之第2光纖之連接機構，由於收容有光纖 之前端部之容器內，充滿有循環，之鈍性氣體，或是對於光 纖所傳遞之光而言係透明不會因該光而分解之液體，即使 在此構造中，若是核心之前端遍佈全面而未接觸之場合時， 該未接觸之部分會成爲與鈍性氣體以及液體接觸之狀態。 因此，引起前述之集塵效果之有機物等與光纖傳遞之雷射 光不會產生光化學反應，能夠抑制在光纖前端所產生之集 塵效果。 又，使用於前述第1與第2光纖之連接構造之鈍性氣體 或是液體，使用未含有矽類有機物之物件之場合時，能夠 防止該物件與雷射光進行學反應而產生污染物質。 又，依本發明在第3光纖之連接機構，由於包含核心前 端之光纖之前端部係藉由以熔融狀態供應到該前端部之後 進行凝固，對於光纖所傳遞之光而言係透明不會因該光而 分解之固體與外部加以隔絕，即使在此構造中，若是核心 之前端遍佈全面而未接觸之場合時，該未接觸之部分會成 爲與鈍性氣體以及液體接觸之狀態。從而，在此種構造， 引起前述之集塵效果之有機物等與光纖傳遞之雷射光不會 產生光化學反應，能夠抑制在光纖前端所產生之集塵效果。 以上所說明之本發明之第1到第3光纖之連接構造，由 於並非將兩條光纖進行融合，所以不需要龐大融合機能夠 簡便地將兩條光纖連接之構造。 -1 0 - 1286229 接著，在兩條光纖之前端部之連接方面，可採用習知之 連接器等之可拆裝之適當機構，如此，除了以熔融後會凝 固之固體覆蓋連接部般之第3連接構造以外，一旦將兩條 之光纖連接之後，能夠簡單地重新連接。 又，依本發明，在光纖之連接機構，特別是在適用兩條 光纖之前端部分別固定於各套圈上，套圈係在各光纖之核 心前端互相相向之狀態穿插過共通之套筒管，各套圈係維 持在前述兩條光纖之核心前端互相接觸之狀態之構造之場 合時，僅令套圈穿插於成爲導件之套筒管，固定於該套圈 之光纖彼此會自動地聚集在同一軸上，光纖之調芯作業亦 變得容易。 又，依本發明，在光纖之連接機構，在封入於密閉空間 或是循環於前述容器內之前述鈍性氣體中，混入有濃度 lppm以上之氧氣、鹵素氣體及/或是鹵素化合物之氣體之 場合時，碳水化合堆積物受到氧化分解而減少的同時，由 於矽類化合物所造成之堆積物受到鹵素氣體加以分解、去 除而減少，特別是能夠獲得信賴性高之光纖之連接構造。 又，施加於光纖之射出端面以及入射端面上之包覆之最 表面層，對於鹵素氣體以及鹵素化合物爲不活潑性材料加 以構成之場合，藉由反映性高知此類氣體能夠防止光纖之 端面惡化。 (四）實施方式 以下，將參照圖面詳細說明本發明之實施形態。 第1圖係本發明之第1實施形態之光纖之連接構造之側 1286229 視剖面形狀之示意圖。此光纖之連接構造係具有穿插有兩 條多種模式光纖（以下僅稱爲光纖）11、1 2之個前端部’將 該前端部加以固定之兩個圓筒形之套圈丨3、14’固定於套 圈1 3、1 4之個後端部附近之圓形凸緣1 5、1 6，套圏1 3、1 4 所穿插之連接器24，在凸緣15之內側而安裝於套圈13之 外圍之〇型環27，在凸緣16之內側而安裝於套圏14之外 圍之〇型環28。 前述套圈13、14係由陶瓷、玻璃、或金屬、又或是前 述各項之組合所構成之材料所形成。在由陶瓷或是玻璃所 形成之場合時，其側面以電鍍金屬、或是利用噴鍍所進行 之金屬化加工爲佳。然後，安裝光纖11、12之各前端部之 後，將套圈13、14之前端硏磨成平坦或是球面狀。 又，連接器24乃是具有僅較套圈13、14之外徑稍微大 之內徑之套筒管20之兩端處分別形成凸緣部21、22的同 時，該套筒管20之中央附近形成有具有連通其內部與外部 之貫穿孔23a之氣體導入部23。前述氣體導入部23之外圍 形成有螺紋，該部分係藉由旋合安裝有封閉貫穿孔23a之 閥25。 又，對於前述套筒1 3、1 4之凸緣1 5、1 6，係如圖中黑 點a所示之部位遍佈全周處例如以焊錫加以固定。此銲錫， 以使用不會發生有機氣體即所謂的無助熔劑銲錫爲佳。 又，分別將套圈1 3、1 4由前端部穿插到連接器24內之 後，前述凸緣15、16其間經由0型環27、28，以適當數 量之螺栓29固定於連接器25之凸緣21、22。然後，連接 -12- 1286229 器2 4之內部對於外部係藉由〇型環2 7、2 8以及凸緣1 ί Ιό進行封閉固定。又，由此，固定於套圈13、14之兩條 纖1 1、1 2之核心前端互相以同軸狀態進行壓接，光纖η 1 2會互相地作光學性連接。又，前述〇型環2 7、2 8以 用由氟類樹脂所構成之物件爲佳。 如以上所述般在連接光纖1 1、1 2之際，將連接器24 部分放置於前述之鈍性氣體之氣體環境中，藉由將閥25 接於未圖示之真空幫浦使連接器24之內部進行檢壓之 式，將鈍性氣體導入連接器24之內部。之後藉由關閉閥 之方式，形成鈍性氣體封入於關閉套圈1 3、1 4形成密閉 間之連接器2 4內部。 由此，若是光纖1 1、1 2之核心前端遍佈全面未接觸 場合時，該未接觸之部分會成爲與前述鈍性氣體接觸之 態。因此，引起前述之集塵效果之有機物等，與光纖1 1、 傳遞之雷射光，不會產生光化學反應，能夠抑制在光纖1 1 12之前端所產生之集塵效果。 在本實施例之場合中，係令波長爲3 5 0〜5 00nm之範 之雷射光在光纖1 1、1 2傳遞，由於在此波長範圍之雷射 容易發現前述之集塵效果，可以說本發明之適用特別具 效果。 又，在將鈍器氣體封入連接器24之內部之前，對連 器24之內部施加脫氣處理時，能夠更確實地抑制集塵效择 又，依據本實施形態之光纖之連接構造，由於並非將 條光纖1 1、1 2之物件進行融合，不需要龐大之融合機而 - 1 3 _ 光 使 之 連 方 25 空 之 狀 12 圍 光 有 接 • 〇 兩 能 1286229 夠簡單地將兩條光纖1 1、1 2連接。·然後，套圈1 3、1 4係 藉由鬆開拆下螺栓29之方式，分別能夠簡單地取下連接器 24，所以一旦將兩條光纖1 1、1 2連接之後，亦能夠簡單地 重新連接。 此外，在本實施形態之光纖之連接構造中，僅將套圈 13、14穿插過成爲導件之套筒管20，固定於該套圏13、14 之光纖11、12彼此會自動地聚集在同一軸上，光纖之調芯 作業亦變得容易。 又，前述鈍性氣體中最適合係可例舉氮氣、稀有氣體等。 又，此鈍性氣體中，以含有濃度爲lppm以上30 %以下之氧 氣、鹵素氣體以及鹵素化合物中至少一種之氣體爲佳。鹵 素氣體以及鹵素化合物之氣體之最佳實施例係如前面所 述。 當鈍性氣體中含有濃度爲1 ppm以上之氧氣時，能夠更 有效地抑制光纖1 1、1 2之惡化。能夠獲得前述效果之提高， 乃是鈍性氣體中之氧氣，藉由碳水成分之光分解所產生之 固形物進行氧化分解之故。又，爲了使氧氣包含於前述封 閉氣體環境，亦可將乾淨空氣（大氣成分）封入連接器24內 部。 又，即使前述鈍性氣體中含有鹵素氣體以及鹵素化合物 中至少一種，同樣地能夠抑制光纖1 1、1 2之惡化。雖然此 類鹵素氣體由微量即可發揮抑制惡化效果，爲了獲得顯著 之惡化抑制效果，以含有濃度爲1 p p m以上之鹵素氣體爲 佳。能夠獲得如此之抑制惡化效果，乃是包含於封閉氣體 一 1 4 - 1286229 環境之鹵素氣體會將藉由有機矽化物氣體之光分解所產生 之堆積物加以分解之故。 又，光纖1 1、1 2之前端互相受到緊密連接固定，不需 要特別形成包覆膜。在未形成包覆膜之場合中，由於不會 產生折射率段差，一般而言，傳遞光之結合效率最高。 但是，根據必要亦可在其前端形成適當之包覆膜。在該 場合中，作爲所披覆之包覆膜之最表面層之材料，若是使 用矽Si、鉬Mo、鉻Cr、錫Sn又或者是鉻Zr之氧化物或 是氮化物等對於鹵素氣體具有反應性之材料之場合時，包 覆膜之最表面層會受到飽刻，降低使用光纖11、12之裝置 之信賴性。 因此，作爲披覆光纖11、12前端之包覆膜之最表面層 之材料，例如以使用銦、鎵、鋁、鈦、鉅之氧化物或是氮 化物般之對於鹵素氣體爲不活潑性之材料爲佳。 又，爲了將鈍性氣體封入連接器24之內部，除了如前 述般進行之外，亦可將加壓後之鈍性氣體通過閥25導入連 接器24之內部。 此外，更可藉由將套圈13、14壓入套筒管20之方式進 行封閉固定，以取代使用〇形環27、28封閉連接器24之 內部。 接著，針對第2實施形態之光纖之連接構造加以說明。 又，在此第2圖中，與第1圖之元件同等之元件覆加上相 同符號，針對該類元件之說明若無特別需要將其省略（以下 均相同）。 -15- 1286229 在本第2實施形態之光纖之連接構造中，分別固定光纖 1 1、1 2之前端部之之套圈1 3、1 4係穿插過1條圓筒狀之套 筒管3 0，在兩條光纖1 1、1 2之核心前端互相以進行壓接之 狀態下，套圈1 3、1 4係固定於套筒管3 〇。此項固定，係例 如在由如圖中黑點a所示之部位遍佈全周處例如以焊錫加 以封閉固定。將前述藉由焊接之固定，藉由在鈍性氣體之 氣體環境中進行之方式，將鈍性氣體封入套筒管3 0之內部。 由此，即使在本實施形態中，亦可獲得與第1實施形態 中同樣之效果。但是在本構造中，要將一旦連接過之光纖 1 1、1 2，各元件維持原狀地重新連接係不可能。 又，在以上所說明之第1以及第2實施形態中，即使使 用對於光纖11、12所傳遞之光而言係透明且不會因該光而 分解之液體取代鈍性氣體，亦可獲得同樣的效果。該液體 例如可適當使用純水。 接著，針對本發明之第3實施形態之光纖之連接構造加 以說明。第3圖及第4圖分別爲第3實施形態之光纖之連 接構造之全體斜視形狀之示意圖與側視剖面形狀之示意 圖。本光纖之連接構造，係將通常之連接器40收容於容器 60內的同時，在容器60內設置有使動性氣體循環之機構之 物件。 前述連接器40，係由穿插過兩個圓筒形之套圈13、14 之前端部之套筒管41、具有使維持於套圈13、14之光纖11、 1 2分別通過之孔，收容有套圈1 3、1 4之後端部之外管43、 44、設置於該外管43、44之底面與套圈13、14之間之壓 一 1 6 - 1286229 縮彈簧45、46所構成。 套筒管41之兩端外圍上形成有公螺絲，外管43、44 前端內圍上形成有母螺絲，兩者可進行旋合。因此，分 將套圈1 3、1 4之各前端部穿插過套筒管4 1，將後端部穿 過外管43、44之後，旋轉外管43、44而旋合於套筒管 時，套圈1 3、1 4之前端彼此會成爲接觸狀態。由此更將 管43、44加以旋緊時，壓縮彈簧45、46之作用下，套圈13 1 4之前端彼此也就是光纖1 1、1 2之前端彼此會成爲壓接 態，光纖1 1、1 2會互相作光學性連接。 容器60係具有上側箱體6 1與下側箱體62所構成之 下分割爲二之構造，上側箱體6 1與下側箱體62係經由 鏈6 3可搖動地受到維持，藉由閂鎖金屬零件64在互相 體化狀態下受到固定。然後上側箱體6 1與下側箱體62 別設置有氣體供應口 65、氣體排出口 66。又，上側箱體 與下側箱體62之左右側壁上，分別形成有半圓形之開口 該部分設置有圓筒形之光纖承接部67、68。此光纖承接 67、68例如係由氟類橡膠等之彈性元件所構成，在與通 其中空部之光纖1 1、1 2之間，以及與呈現受到關閉狀態 鄕體6 1、62之間維持著氣體密閉狀態。 氣體供應口 65、氣體排出口 66係連接於氣體循環配 70，在此氣體循環配管70之圖中，係設置有儲存前述鈍 氣體之除氣槽71以及氣體輸送幫浦72。在本實施例中， 由以上之氣體循環配管70、除氣槽71以及氣體輸送幫浦 構成流體循環裝置。 之 別 插 4 1 外 狀 上 鉸 分 61 部 之 管 性 藉 Ί2 - 17 - 1286229 光纖1 1、1 2係分別通過光纖承接部67、68之後，使用_ 連接器40如前述般互相作光學性連接。此連接器4〇之部 分係維持於下側箱體62之底面上，上側箱體6 1由其上方 加以關閉，藉由閂鎖金屬零件64加以鎖緊之方式兩箱體 6 1、62維持氣體密閉狀態而一體化。如此使光纖1 1、i 2之 前端部進行連接之連接器40之部分，成爲收容於容器60 中之狀態。又，兩箱體61、62其互相接觸之端面部分，以 藉由施加由氟類橡膠等彈性材料所構成之包覆之方式，使 兩箱體6 1、62間之氣體密閉狀態更加確實爲佳。 連接器40之部分收容到容器60中時，氣體輸送幫浦72 會受到驅動，由此，儲氣槽71內所儲蓄之鈍性氣體會通過 容器60內受到循環。此鈍性氣體，可使用適合於第1實施 形態所使用之氣體。 然後，若是光纖1 1、1 2之核心前端遍佈全面未接觸之 場合時，該未接觸之部分會成爲與前述鈍性氣體接觸之狀 態。因此，引起前述之集塵效果之有機物等與光纖1 1、1 2 傳遞之雷射光不會產生光化學反應，能夠抑制在光纖1 1、1 2 之前端所產生之集塵效果。 在本實施例之場合中，係令波長爲3 5 0〜5 00nm之範圍 之雷射光在光纖1 1、1 2傳遞，由於在此波長範圍之雷射光 容易發現前述之集塵效果，可以說本發明之適用特別具有 效果。 又，在使鈍器氣體進行循環之前，對收容有連接器40 之容器60之內部施加脫氣處理時，能夠更確實地抑制集塵 一 1 8- 1286229 效果。 又，本實施形態之光纖之連接構造，由於並非將兩條光 纖1 1、1 2之物件進行融合，不需要龐大之融合機而能夠簡 單地將兩條光纖1 1、1 2連接。然後，套圈1 3、14係藉由 鬆開拆下連接器4 0之外管4 3、44之方式，分別能夠簡單 地取下連接器4 0，所以一旦將兩條光纖1 1、1 2連接之後， 亦能夠簡單地重新連接。 此外，在本實施形態之光纖之連接構造中，僅將套圈 13、14穿插過成爲導件之套筒管41，固定於該套圈13、14 之光纖11、12彼此會自動地聚集在同一軸上，光纖之調芯 作業亦變得容易。 又’在此場合’只要含有濃度爲lppm以上之氧氣、鹵 素氣體以及鹵素化合物中至少一種之氣體，能夠同樣地獲 得在第1實施形態所說明般之效果。又，可使用純水等之 液體’取代前述鈍性氣體之方式，亦與第1實施形態相同。 此外，分別將形成於上側箱體6 1與下側箱體62之氣體 供應口 65、氣體排出口 66關閉，或者是藉由最初即便省略 之方式將容器6 0形成密閉容器的話，亦可將鈍性氣體或是 純水等之液體封入後使用。 接著’參照第5圖針對本發明之第4實施形態加以說明。 在本第4實施形態之光纖之連接構造中，分別固定光纖1 i、 12之前端部之之套圈13、14係穿插過1條圓筒狀之套筒管 8 0，在光纖1 1、1 2之核心前端互相以進行壓接之狀態下， 套圈1 3、1 4係固定於套筒管8 0。此項固定，係例如在由如 -19- 1286229 圖中黑點a所示之部位遍佈全周處例如以焊錫加以封閉固 定。 前述套筒管80之中央附近之一部，形成有切口 80a。 然後，如前述般將套圈1 3、1 4固定於套筒管8 0之後，將 熔融狀態之低熔點玻璃8 1流入此切口 8 0，流動之熔融狀態 之低熔點玻璃會一邊將光纖1 1、1 2其連接部之空氣推出而 通過此部份，逐漸地冷卻後凝固。 又，在本實施例之場合中，雖然令波長爲3 5 0〜500nm 之範圍之雷射光在光纖1 1、1 2傳遞，低熔點玻璃8 1對與 此波長範圍之雷射光而言係爲透明，又爲不因此光受到分 解之物件。 如以上所述般，在本實施形態中，包含核心之前端之光 纖1 1、1 2之前端部藉由在熔融狀態下供應到該前端部後凝 固之低熔點玻璃81形成與外部隔絕之狀態。因此，若是光 纖11、1 2之核心前端遍佈全面未接觸之場合時，該未接觸 之部分會成爲與低熔點玻璃接觸之狀態。因此，在此構造 中，引起前述之集塵效果之有機物等與光纖11、12傳遞之 雷射光不會產生光化學反應，能夠確實地抑制在光纖1 1、1 2 之前端所產生之集塵效果。 (五）圖式之簡單說明 第1圖係本發明之第1實施形態之光纖之連接構造之 側視剖面圖。 第2圖係本發明之第2實施形態之光纖之連接構造之 側視剖面圖。 - 20 - 1286229 第3圖係本發明之第3實施形態之光纖之連接構造之 全體斜視圖。 第4圖係本發明之第3實施形態之光纖之連接構造之 側視剖面圖。 第5圖係本發明之第4實施形態之光纖之連接構造之 側視剖面圖。 [符 號之 說明 ] 1卜 12 多 重 模 式 光 纖 13 ^ 14 套 圈 15、 16 凸 緣 21、 22 連 接 器 之 凸 緣 部 24 連 接 器 25 閥 11、 28 0 型 環 30 套 筒 管 40 連 接 器 41 連 接 器 之 套 筒 管 43、 44 連 接 器 之 外 管 60 容 器 65 氣 體 供 應 □ 66 氣 體 排 出 □ 67、 68 光 纖 承 接 部 70 /氣 體 循 環 配 管 7 1 儲 氣 槽 -21- 1286229 72 氣體輸送幫浦 80 套筒管 8 1 低熔點玻璃 -22-1286229 玖, DESCRIPTION OF THE INVENTION: (I) Field of the Invention The present invention relates to a configuration in which two optical fibers are connected. (2) Prior art In the past, a structure in which two optical fibers are connected is roughly classified into two structures and is known. One is a configuration in which the front ends of the two optical fibers are fused together in a state where the cores are gathered at the same axis. Alternatively, the two optical fibers are connected in a state in which the front ends of the respective cores are in contact with each other without being fused. The latter has a specific structure. For example, as described in Japanese Patent Publication No. Hei 4-693, the two ferrules of the ends of the two optical fibers are respectively fixed, and the collars are interposed at the core front ends of the respective optical fibers. It is widely known that a sleeve tube that has been used in common and a support mechanism that maintains each of the ring systems in a state in which the core ends of the two optical fibers are in contact with each other are formed. [Patent Document] Japanese Patent Publication No. Hei 4-69369 (Problem to be Solved by the Invention) However, the wavelength emitted in the short wavelength, particularly the wavelength emitted by the Ga nano-based semiconductor laser, is 305 to 5 〇 Onm. In terms of the device of the light, it is known that light having a high optical density of the optical element passes through the end face, and a vaporized organic substance and a substance which is photochemically reacted with the laser light are accumulated, that is, a so-called dust collecting effect is produced. When the light of the optical element is adhered to the end surface by the contaminant, the semiconductor laser drive current necessary for obtaining a predetermined light output is increased, and the transmission loss of the laser light is increased. Also, it is known that the effect of the enthalpy is that the carbide is the cause and the cause of the cesium alkane is 5-5286229. Even in the above-mentioned optical fiber, in the case of the short-wavelength light transmitted as described above, a collecting effect is generated on the incident end surface or the output end surface of the core. Therefore, even at the joint portion of the two optical fibers, the end faces of the core are completely and completely in contact with each other, and if one of the end faces is formed in contact with the outside air, a dust collecting effect is generated. In the connection structure in which the two optical fibers are fused as described above, generally, since the end faces of the core are completely joined to each other completely, the dust collecting effect is not generated. However, for this configuration, it is necessary to have a dedicated high-priced fusion machine. In addition to complicated work, there is also a problem that the fusion machine cannot be prepared due to the job site. Further, in the case of this connection structure, if the optical fiber that has been connected is reconnected, it is necessary to accept the merging of the fusion portion to perform the fusion operation again. On the other hand, even in a configuration in which the two fibers are not fused and the front ends of the cores are connected to each other, the end faces of the cores are completely in contact with each other, and the dust collecting effect is not generated. In the case of a single mode fiber, since the fiber is connected by pushing the fiber as a whole, it is difficult to produce a dust collecting effect. However, in the case of a fiber having a large core diameter of a plurality of modes, it is difficult to integrally contact the core end faces with each other, and thus a state in which one of the core end faces is in contact with the outside air is formed, which is liable to cause a dust collecting effect. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an object of preventing a dust collecting effect at the front end of an optical fiber which is connected to each other, and which does not require a bulky fusion machine to easily connect two optical fibers. Further, in addition to the above, the present invention has an object of providing a connection structure of an optical fiber which can be easily reconnected once the two optical fibers are connected. (3) Disclosure of the Invention (Method for Solving the Problem) The first optical fiber connection structure of the present invention connects two optical fibers without being fused, and is connected in a state in which the front ends of the cores are in contact with each other, and is characterized in that the optical fiber including the core front end is connected. The front end portion is housed in a sealed space, and the sealed light is sealed with a passive gas or a liquid that is transparent to light transmitted by the optical fiber and is not decomposed by the light. In the connection structure of the second optical fiber according to the present invention, the two optical fibers are connected without being fused, and the front ends of the cores are in contact with each other, and the front end of the optical fiber including the core front end is received. In a container connected to the fluid supply port of the fluid circulation device and the fluid discharge port, the container is filled with a circulating passive gas, or a liquid transparent to the light transmitted by the optical fiber without being decomposed by the light. . Further, in the connection structure of the first and second optical fibers of the present invention, the so-called connection of the two optical fibers does not mean that the single optical fibers are connected to each other, and the optical fiber arrays or the optical fiber bundles are mutually connected. In the case of connected objects, the optical fiber arrays are either one to another or the ones of the optical fibers in the bundle. In addition, the term "passive gas" as used herein refers to a gas which is not active for a material constituting an optical fiber or a connector, and specific examples thereof include a rare gas such as dry nitrogen or argon. Further, in the connection structure of the first optical fiber, when the blunt 7-1286229 gas is sealed in the sealed space, and when the container is filled with a passive gas in the connection structure of the second optical fiber, the passive gas is mixed therein. It is preferred to have a concentration of 1 ppm or more of oxygen, a halogen gas, and/or a halogen compound. That is to say, the internal gas atmosphere of the package is (1) a gas in which a passive gas is mixed with oxygen having a concentration of 1 ppm or more, and (2) at least a gas of any one of a passive gas and a halogen gas and a halogen compound gas. As the gas to be mixed, (3) a gas in which a passive gas is mixed with at least 1 ppm of oxygen, a halogen gas, and a halogen compound gas with at least one of the gases. Further, the halogen gas and the halogen compound preferably contain a fluorine atom. Further, the halogen compound gas is preferably at least one selected from the group consisting of fluorides such as carbon, nitrogen, sulfur, and antimony, and chlorides such as carbon, nitrogen, sulfur, and antimony. The halogen gas means a halogen gas such as chlorine gas Cl2 or fluorine gas F2, and the gas of the halogen compound means a gaseous compound containing a halogen atom such as chlorine C1, bromine Br, iodine I or fluorine F. Examples of the halogen compound gas include CF3C1, CF2C12, CFC13, CF3Br, CC14, CCl4-02, C2F4C12, Cl-H2, CF3Br, PC13, CF4, SF6, NF3, XeF2, C3F8, CHF3, etc., with fluorine or chlorine. A compound of carbon element C, nitrogen N, sulfur S, or xenon Xe is preferred, and a gas containing a fluorine atom is particularly preferred. Further, it is preferable that the outermost layer of the coating applied to the exit end face of the optical fiber and the incident end face is made of an inert material for the halogen gas and the halogen compound. The inactive material is preferably at least one selected from the group consisting of various oxides of indium, gallium, aluminum, titanium, lanthanum 8- 1286229, and various nitrides of indium, gallium, aluminum, titanium, and antimony. Further, the passive gas or the liquid used in the connection structure between the first and second optical fibers is preferably an article not containing a quinone organic substance. Further, in the connection structure of the third optical fiber according to the present invention, the two optical fibers are not required to be fused in the same manner as described above, and are connected in a state in which the front ends of the cores are in contact with each other. The feature is that the front end of the optical fiber including the core front end is By solidifying after being supplied to the tip end portion in a molten state, it is transparent to the light transmitted from the optical fiber, and the solid which is not decomposed by the light is isolated from the outside. Here, as the solid described above, a low melting point glass or the like can be preferably used. Further, in the specific structure in which the two optical fibers are not fused and connected as described above, for example, the front ends of the two optical fibers are respectively fixed to the respective ferrules, and the ferrules are in a state in which the core front ends of the optical fibers are opposed to each other. A common sleeve tube is inserted, and each ferrule is maintained in a state in which the core front ends of the two optical fibers are in contact with each other. Further, in the connection structure of the optical fiber of the present invention, it is preferable that the wavelength of the light transmitted by the two optical fibers is in the range of 305 to 5,000 nm. (Effect of the Invention) In the first optical fiber connecting mechanism of the present invention, the passive space in which the end portion of the optical fiber is accommodated is sealed with a passive gas or is transparent to the light transmitted from the optical fiber. A liquid that decomposes by light. If the front end of the core is completely untouched, the untouched portion will be in contact with the passive gas and the liquid. Therefore, the laser light which causes the above-mentioned dust collecting effect and the organic light transmitted from the optical fiber does not cause a photochemical reaction, and can suppress the dust collecting effect generated at the front end of the optical fiber. Further, in the second optical fiber connecting mechanism of the present invention, the container in which the end portion of the optical fiber is accommodated is filled with a circulating passive gas, or is transparent to the light transmitted from the optical fiber. The decomposed liquid, even in this configuration, if the front end of the core is spread over the entire area without contact, the untouched portion becomes in contact with the passive gas and the liquid. Therefore, the organic light or the like which causes the dust collecting effect described above does not cause a photochemical reaction with the laser light transmitted from the optical fiber, and the dust collecting effect generated at the tip end of the optical fiber can be suppressed. Further, when a passive gas or a liquid which is used in the connection structure between the first and second optical fibers is used, and an object which does not contain a quinone organic substance is used, it is possible to prevent the object from reacting with the laser light to generate a contaminant. Further, according to the third optical fiber connecting mechanism of the present invention, since the front end portion of the optical fiber including the core front end is solidified after being supplied to the front end portion in a molten state, it is transparent to the light transmitted from the optical fiber. The solid which is decomposed by the light is isolated from the outside, and even in this configuration, if the front end of the core is spread over the entire area without contact, the uncontacted portion becomes in contact with the passive gas and the liquid. Therefore, in such a configuration, the organic light or the like which causes the dust collecting effect described above does not cause a photochemical reaction with the laser light transmitted from the optical fiber, and the dust collecting effect generated at the tip end of the optical fiber can be suppressed. The connection structure of the first to third optical fibers of the present invention described above is such that the two optical fibers are not fused, so that a structure in which two large optical fibers can be easily connected without a bulky fusion machine is required. -1 0 - 1286229 Next, in terms of the connection of the ends of the two optical fibers, a suitable mechanism such as a conventional connector or the like can be used, so that the third portion is covered by the solid which solidifies after melting. In addition to the connection structure, once the two fibers are connected, it is possible to simply reconnect. Moreover, according to the present invention, the connecting portion of the optical fiber, particularly before the application of the two optical fibers, is respectively fixed to each of the ferrules, and the ferrule is inserted through the common sleeve tube in a state in which the core front ends of the optical fibers face each other. When the ferrules are maintained in a state in which the core front ends of the two optical fibers are in contact with each other, only the ferrule is inserted into the sleeve tube which becomes the guide member, and the optical fibers fixed to the ferrule are automatically gathered from each other. On the same axis, the alignment of the fiber is also easy. Further, according to the present invention, in the connecting means for the optical fiber, a gas having a concentration of 1 ppm or more of oxygen, a halogen gas, and/or a halogen compound is mixed in the passive gas sealed in the sealed space or circulated in the container. In this case, the carbohydrate-deposited material is reduced by oxidative decomposition, and the deposit due to the quinone compound is decomposed and removed by the halogen gas, and in particular, a highly reliable optical fiber connection structure can be obtained. Further, when the outer surface layer of the coating on the exit end face of the optical fiber and the incident end face is formed of an inert material such as a halogen gas or a halogen compound, it is possible to prevent the end face of the optical fiber from being deteriorated by reflecting the gas. . (4) Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic cross-sectional view showing the side of the connection structure of the optical fiber according to the first embodiment of the present invention. The connection structure of the optical fiber has two cylindrical ferrules 3, 14' through which the front end portion of the two types of optical fibers (hereinafter simply referred to as optical fibers) 11 and 12 are inserted to fix the front end portion. a circular flange 15 5, 16 which is fixed near the rear end portions of the ferrules 1 3 and 14 and a connector 24 inserted through the sleeves 13 and 14 are attached to the sleeve inside the flange 15 The 〇-shaped ring 27 on the periphery of the ring 13 is mounted on the inner side of the flange 16 to the 〇-shaped ring 28 on the periphery of the ferrule 14. The ferrules 13, 14 are formed of ceramic, glass, or metal, or a combination of the foregoing. In the case where it is formed of ceramic or glass, the side surface is preferably plated with metal or metallized by sputtering. Then, after the front end portions of the optical fibers 11, 12 are mounted, the front ends of the ferrules 13, 14 are honed to a flat or spherical shape. Further, the connector 24 has a flange portion 21, 22 formed at both ends of the sleeve tube 20 having an inner diameter slightly larger than the outer diameter of the ferrules 13, 14, and the center of the sleeve tube 20 A gas introduction portion 23 having a through hole 23a that communicates between the inside and the outside is formed in the vicinity. A thread is formed on the periphery of the gas introduction portion 23, and the portion is a valve 25 that closes the through hole 23a by screwing. Further, the flanges 15 and 16 of the sleeves 1 3 and 14 are fixed to the entire circumference by a portion indicated by a black dot a in the figure, for example, by soldering. This solder is preferably used without the use of organic gases, so-called fluxless solder. Further, after the ferrules 13 and 14 are respectively inserted into the connector 24 from the front end portion, the flanges 15 and 16 are fixed to the connector 25 by an appropriate number of bolts 29 via the 0-rings 27 and 28, respectively. Edge 21, 22. Then, the inside of the -12-128622 is connected to the outside by means of the 〇-rings 2, 7 and 8 and the flange 1 ί. Further, the core ends of the two fibers 1 1 and 1 2 fixed to the ferrules 13 and 14 are bonded to each other in a coaxial state, and the optical fibers η 1 2 are optically connected to each other. Further, it is preferable that the 〇-shaped rings 27 and 28 are made of a fluorine-based resin. When the optical fibers 1 1 and 1 2 are connected as described above, the connector 24 is partially placed in the gaseous environment of the aforementioned passive gas, and the valve is connected to a vacuum pump (not shown) to make the connector. The inside of the 24 is subjected to a pressure detection method, and a passive gas is introduced into the inside of the connector 24. Thereafter, by closing the valve, a passive gas is formed to be sealed inside the connector 224 which closes the ferrules 13 and 14 to form a closed space. Therefore, if the core front ends of the optical fibers 1 1 and 1 2 are completely untouched, the uncontacted portions come into contact with the passive gas. Therefore, the organic matter or the like which causes the dust collecting effect described above does not cause a photochemical reaction with the optical fiber 11 and the transmitted laser light, and the dust collecting effect generated at the front end of the optical fiber 1 1 12 can be suppressed. In the case of the present embodiment, the laser light having a wavelength of 550 to 50,000 nm is transmitted through the optical fibers 11 and 12, and since the above-mentioned dust collecting effect is easily found by the laser in this wavelength range, it can be said that The application of the invention is particularly effective. Further, when the blunt gas is sealed inside the connector 24, when the degassing treatment is applied to the inside of the connector 24, the dust collecting effect can be more reliably suppressed, and the optical fiber connection structure according to the present embodiment is not The fibers of the fibers 1 1 and 1 2 are fused, and there is no need for a huge fusion machine - 1 3 _ light makes the square 25 empty shape 12 surrounded by light • 〇 two energy 1286229 enough to simply two fibers 1 1, 1 2 connection. Then, the ferrules 1 3 and 14 can be easily removed from the connector 24 by loosening the bolts 29, so that once the two optical fibers 1 1 and 12 are connected, it is also possible to simply reconnect. Further, in the optical fiber connection structure of the present embodiment, only the ferrules 13 and 14 are inserted through the sleeve tube 20 which serves as a guide member, and the optical fibers 11 and 12 fixed to the ferrules 13 and 14 are automatically gathered at each other. On the same axis, the alignment of the fiber is also easy. Further, among the above-mentioned passive gases, nitrogen gas, a rare gas, and the like are exemplified. Further, in the passive gas, a gas containing at least one of oxygen gas, halogen gas, and halogen compound having a concentration of 1 ppm or more and 30% or less is preferable. The preferred embodiment of the halogen gas and the gas of the halogen compound is as described above. When the passive gas contains oxygen having a concentration of 1 ppm or more, deterioration of the optical fibers 11 and 12 can be more effectively suppressed. The improvement in the aforementioned effect is obtained by oxidative decomposition of oxygen in a passive gas by solid matter generated by photolysis of a carbon water component. Further, in order to allow oxygen to be contained in the closed gas atmosphere, clean air (atmospheric component) may be sealed inside the connector 24. Further, even if at least one of the halogen gas and the halogen compound is contained in the passive gas, the deterioration of the optical fibers 11 and 12 can be suppressed in the same manner. Although such a halogen gas exhibits an effect of suppressing deterioration in a small amount, it is preferable to contain a halogen gas having a concentration of 1 p p or more in order to obtain a remarkable deterioration suppressing effect. The effect of suppressing such deterioration can be obtained by the fact that the halogen gas contained in the atmosphere of the closed gas is decomposed by the deposit generated by the decomposition of the organic telluride gas. Further, the front ends of the optical fibers 1 1 and 1 2 are tightly connected to each other, and it is not necessary to form a coating film in particular. In the case where the coating film is not formed, since the refractive index step is not generated, in general, the bonding efficiency of the transmitted light is the highest. However, an appropriate coating film may be formed at the front end as necessary. In this case, as the material of the outermost layer of the coating film to be coated, if cerium, molybdenum Mo, chromium Cr, tin Sn or chromium Zr oxide or nitride is used, the halogen gas has In the case of a reactive material, the outermost layer of the coating film is saturated, reducing the reliability of the device using the optical fibers 11 and 12. Therefore, as a material for coating the outermost layer of the coating film at the tip end of the optical fibers 11, 12, for example, indium, gallium, aluminum, titanium, giant oxide or nitride is inactive for halogen gas. The material is better. Further, in order to seal the inside of the connector 24 with the passive gas, in addition to the above, the pressurized passive gas may be introduced into the inside of the connector 24 through the valve 25. In addition, the closure can be closed by pressing the ferrules 13, 14 into the sleeve tube 20 instead of closing the interior of the connector 24 using the 〇-shaped rings 27, 28. Next, the connection structure of the optical fiber of the second embodiment will be described. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the components is omitted unless otherwise specified (the same applies hereinafter). -15- 1286229 In the optical fiber connection structure according to the second embodiment, the ferrules 1 3 and 14 which are fixed to the front ends of the optical fibers 1 1 and 1 2 are respectively inserted through a cylindrical sleeve tube 3 0. The ferrules 13 and 14 are fixed to the sleeve tube 3 在 in a state in which the core ends of the two optical fibers 1 1 and 1 2 are crimped to each other. This fixing is, for example, fixed at a portion shown by a black dot a in the figure, for example, by soldering. The above-mentioned fixing by welding is carried out by enclosing the passive gas into the inside of the sleeve tube 30 by being carried out in a gaseous environment of a passive gas. Thereby, even in the present embodiment, the same effects as those in the first embodiment can be obtained. However, in the present configuration, it is impossible to reconnect the respective elements once the optical fibers 1 1 and 1 2 are connected. Further, in the first and second embodiments described above, even if a liquid which is transparent to the light transmitted by the optical fibers 11 and 12 and which does not decompose by the light is used instead of the passive gas, the same can be obtained. Effect. For the liquid, for example, pure water can be suitably used. Next, the connection structure of the optical fiber according to the third embodiment of the present invention will be described. Fig. 3 and Fig. 4 are schematic views showing the entire squint shape and the side cross-sectional shape of the optical fiber connection structure of the third embodiment. The optical fiber connection structure is such that the normal connector 40 is housed in the container 60, and the container 60 is provided with an object for circulating the movable gas. The connector 40 is a sleeve tube 41 that is inserted through the front end portions of the two cylindrical ferrules 13, 14 and has a hole through which the optical fibers 11 and 12 held by the ferrules 13 and 14 respectively pass. There are ferrules 1 3, 14 after the end of the outer tubes 43, 44, the pressure between the bottom surface of the outer tubes 43, 44 and the ferrules 13, 14 are formed by a 16 - 1286229 shrink springs 45, 46 . Male screws are formed on the outer periphery of both ends of the sleeve tube 41, and mother screws are formed on the inner circumference of the outer ends of the outer tubes 43, 44, and the two can be screwed. Therefore, the front end portions of the ferrules 13 and 14 are inserted through the sleeve tube 4 1, and after the rear end portion is passed through the outer tubes 43, 44, the outer tubes 43 and 44 are rotated and screwed to the sleeve tube. The front ends of the ferrules 1 3 and 1 4 will become in contact with each other. Therefore, when the tubes 43 and 44 are tightened, the front ends of the ferrules 13 1 4 and the front ends of the optical fibers 1 1 and 1 2 become pressed into each other under the action of the compression springs 45 and 46, and the optical fibers 1 1 1, 2 will be optically connected to each other. The container 60 has a structure in which the upper case 61 and the lower case 62 are divided into two, and the upper case 61 and the lower case 62 are swayably held by the chain 63, by latching The lock metal part 64 is fixed in an inter-body state. Then, the upper casing 61 and the lower casing 62 are provided with a gas supply port 65 and a gas discharge port 66. Further, on the left and right side walls of the upper casing and the lower casing 62, semi-circular openings are formed in this portion, and cylindrical optical fiber receiving portions 67, 68 are provided in this portion. The optical fiber receiving members 67, 68 are formed, for example, of an elastic member such as a fluorine rubber, and are maintained between the optical fibers 11 and 12 which pass through the hollow portion, and between the bodies 6 1 and 62 which are subjected to the closed state. The gas is sealed. The gas supply port 65 and the gas discharge port 66 are connected to the gas circulation port 70. In the figure of the gas circulation pipe 70, a degassing tank 71 for storing the blunt gas and a gas delivery pump 72 are provided. In the present embodiment, the above-described gas circulation piping 70, degassing tank 71, and gas delivery pump constitute a fluid circulation device. The insertion of the outer part of the outer surface of the outer part of the outer surface of the outer surface of the outer surface of the outer surface of the outer surface of the outer surface of the outer surface of the outer surface of the outer surface of the optical fiber 1 and the second and second and second and second connection. The portion of the connector 4 is maintained on the bottom surface of the lower casing 62, and the upper casing 61 is closed by the upper portion thereof, and the two casings 6 1 and 62 are maintained by the locking metal fitting 64. The gas is sealed and integrated. The portion of the connector 40 that connects the distal ends of the optical fibers 1 1 and i 2 in this manner is housed in the container 60. Further, the end faces of the two casings 61 and 62 which are in contact with each other are sealed so as to form a gas-tight state between the two casings 61 and 62 by applying a coating made of an elastic material such as fluorine rubber. good. When the portion of the connector 40 is housed in the container 60, the gas delivery pump 72 is driven, whereby the passive gas stored in the reservoir 71 is circulated through the container 60. As the passive gas, a gas suitable for use in the first embodiment can be used. Then, if the core front ends of the optical fibers 1 1 and 12 are completely untouched, the uncontacted portions may be in contact with the passive gas. Therefore, the laser light transmitted from the organic matter or the like which causes the dust collecting effect described above and the optical fibers 1 1 and 12 does not cause a photochemical reaction, and the dust collecting effect generated at the front ends of the optical fibers 1 1 and 1 2 can be suppressed. In the case of the present embodiment, the laser light having a wavelength of 550 to 50,000 nm is transmitted through the optical fibers 11 and 12, and since the laser light in this wavelength range is easy to find the dust collecting effect described above, it can be said that The application of the invention is particularly effective. Further, when the deaeration treatment is applied to the inside of the container 60 in which the connector 40 is housed before the blunt gas is circulated, the effect of the dust collection 1-8 1286229 can be more reliably suppressed. Further, in the optical fiber connection structure of the present embodiment, since the two optical fibers 11 and 12 are not fused, the two optical fibers 1 1 and 1 2 can be easily connected without requiring a bulky fusion machine. Then, the ferrules 1 3, 14 can be simply removed from the connector 4 3, 44 by loosening the connector 40, respectively, so that once the two fibers 1 1 and 1 are 2 After connecting, you can also simply reconnect. Further, in the optical fiber connection structure of the present embodiment, only the ferrules 13 and 14 are inserted through the sleeve tube 41 which serves as a guide member, and the optical fibers 11, 12 fixed to the ferrules 13, 14 are automatically gathered at each other. On the same axis, the alignment of the fiber is also easy. In this case, as long as the gas containing at least one of oxygen, a halogen gas, and a halogen compound having a concentration of 1 ppm or more is contained, the effects as described in the first embodiment can be obtained in the same manner. Further, a method in which the liquid "such as pure water" is used instead of the above-mentioned passive gas is also the same as in the first embodiment. Further, the gas supply port 65 and the gas discharge port 66 formed in the upper case 61 and the lower case 62 are respectively closed, or the container 60 can be formed into a closed container by first omitting the case. A liquid such as a blunt gas or pure water is used after being sealed. Next, a fourth embodiment of the present invention will be described with reference to Fig. 5. In the optical fiber connection structure according to the fourth embodiment, the ferrules 13 and 14 which are fixed to the front end portions of the optical fibers 1 and 12, respectively, are inserted through one cylindrical sleeve tube 80, and the optical fiber 11 is In the state in which the core front ends of 1 2 are crimped to each other, the ferrules 1 3 and 14 are fixed to the sleeve tube 80. This fixing is, for example, fixed at a portion indicated by a black dot a in the figure of -19-1286229, for example, by soldering. A slit 80a is formed in a portion near the center of the sleeve tube 80. Then, after the ferrules 13 and 14 are fixed to the sleeve tube 80 as described above, the molten low-melting glass 8 1 flows into the slit 80, and the molten low-melting glass will flow the optical fiber 1 1, 1 2 The air of the connecting portion is pushed out through this portion, gradually cooled and solidified. Further, in the case of the present embodiment, the laser light having a wavelength of 550 to 500 nm is transmitted through the optical fibers 11 and 12, and the low-melting glass 8 1 is for the laser light of the wavelength range. Transparent, and it is an object that is not decomposed by light. As described above, in the present embodiment, the front end portion of the optical fibers 1 1 and 1 2 including the front end of the core is separated from the outside by the low-melting glass 81 which is solidified after being supplied to the front end portion in a molten state. . Therefore, if the core front ends of the optical fibers 11 and 12 are not completely contacted, the uncontacted portions come into contact with the low-melting glass. Therefore, in this configuration, the laser light transmitted from the organic matter or the like which causes the dust collecting effect described above and the optical fibers 11 and 12 does not cause a photochemical reaction, and the dust generated at the front end of the optical fibers 1 1 and 1 2 can be surely suppressed. effect. (Embodiment) Brief Description of the Drawings Fig. 1 is a side sectional view showing the connection structure of an optical fiber according to a first embodiment of the present invention. Fig. 2 is a side sectional view showing the connection structure of an optical fiber according to a second embodiment of the present invention. - 20 - 1286229 Fig. 3 is a perspective view showing the entire structure of the optical fiber connection structure according to the third embodiment of the present invention. Fig. 4 is a side sectional view showing the connection structure of an optical fiber according to a third embodiment of the present invention. Fig. 5 is a side sectional view showing the connection structure of an optical fiber according to a fourth embodiment of the present invention. [Description of symbols] 1 Bu 12 Multimode fiber 13 ^ 14 Ferrules 15, 16 Flange 21, 22 Flange of connector 24 Connector 25 Valve 11, 28 0 Ring 30 Sleeve tube 40 Connector 41 Connection Sleeve tube 43, 44 connector outside tube 60 container 65 gas supply □ 66 gas discharge □ 67, 68 fiber receiving unit 70 / gas circulation piping 7 1 gas storage tank - 2186229 72 gas delivery pump 80 sets Bobbin 8 1 low melting glass-22-