玖、發明說明（1 ) 【發明所屬之技術領域】 本發明是有關於一種增益平坦濾波器，特別是指一種 適用於串接摻铒光纖放大器使光訊號增益平坦化之增益平 坦濾波器。 5【先前技術】 以光纖為骨幹所發展之全光網路（AON)系統，可提供 資料高速、非常大容量的傳輸需求，其中，摻铒光纖放大 器（EDFA)是在全光網路系統中最重要的單元組件之一，但 是由於铒原子能階的影響，摻铒光纖放大器的輸出光譜會 10 出現兩個共振峰的不平坦現象，並且在放大光信號之後也 將會造成放大之光信號功率不同而影響通訊系統接收端對 於光信號與雜訊的辨別，甚至於產生誤判等現象，因此為 確保光纖通訊系統在一寬廣頻帶間的多頻道訊號之光功率 保持一定，將摻铒光纖放大器之輸出增益平坦化實為光纖 15 通訊發展的一項重要課題。 長週期光纖光栅（LPG Long Period Fiber Gratings) 首先是由Ashish M.Vengsarkar等人於1995年提出，並在 1996年分別提出其在帶拒濾波器、溫度感測與摻餌光纖 放大器增益平坦方面的研究，為近年來發展最快速的光被 20 動元件之一；由於長週期光纖光柵可將光纖纖核（core)中 的基本模態（fundamental mode)輕合至正向傳播的纖殼模 態（cladding mode)，這些模態在沿光纖軸向傳播時，將因 纖殼與折射率較小的介質（如空氣）接面或是光纖之彎曲產 生散射或被吸收而快速衰減，造成長週期光纖光柵穿透光 7 1221537 玖、發明說明C2) 譜中的數個損失峰(共振波長)出現（如第一圖所示），因 此只要能夠適當的調變這些損失峰即可遽除推解光纖中增 益不平坦的部分，實現增益平坦化的目標。 5 10 一般以改變長週期光纖光栅之週期來調變其穿透光 譜中損失峰之位置與強度時，將有調變大小不易控制的問 題產生，因此，如何準確改變長週期光纖光栅的週期，以 調變輸出光譜中損失峰的位置與強度，而實現將掺斜光纖 放大器增益平坦化的技術適用於光通訊工業中，是當前業 界與學界共同努力的目標。 【發明内容】 因此，本發明之首要目的，即在提供一種具有長週期 光纖光柵之增益平坦濾波器，使通過之光訊號依設定增益 平坦化。 此外，本發明之另一目的，即在提供製造具有長週期 15 光纖光柵之增益平坦濾波器的製造方法，以精確且大量寫 製長週期光纖光栅之週期，達成商業化量產的目標。 於是，本發明之一種具有長週期光纖光柵之增益平坦 濾、波器’熔接於一具有一第一直徑之纖殼的第一光纖，與 一具有一第二直徑之纖殼的第二光纖之間，該第一光纖相 20 反於熔接該增益平坦濾波器之另一端是與一可輸出一光訊 號之輸出源相串接，且該第二光纖相反於溶接該增益平土曰 濾波器之另一端是與一光訊號放大器相串接，該增益平坦 濾波器包含一具有相反之一輸入端與一輸出端之光纖光栅 ，該輸入端與該第一光纖熔接，該輸出端與該第二光纖相 8 玖、發明說明（3.: ) 熔接。 其特徵在於該光纖光栅之—光撕週期遠大於光之波長 ’包含至少-具有—預定濾波直徑之纖殼的濾波光纖，該 每-濾波直徑均相異於該第―、二直徑，使㈣波光纖之 一纖殼模態被調變，而使該輸出源輸出之—光訊號通過該 光纖光栅後可被瀘、除該光訊號之—預定波長範圍的一不平 坦部，使光訊號平坦化。 10 15 20 再者，本發明之一種具有長週期光纖光柵之增益平坦 渡波器的製造方法，是製造一熔接於一具有一第一直徑之 纖成的第-光纖’與—具有二直徑之纖殼的第二光纖 之間的增益平坦濾波器，該第一光纖相反於熔接該增益平 坦濾波器之另一端是與一可輸出一光訊號之輸出源相串接 ，且該第二光纖相反於熔接該增益平坦濾波器之另一端是 與一光訊號放大器相串接，該製造方法是先將一光纖寫製 成一具有一光柵週期之光纖光栅，且該光纖光柵具有相反 之一輸入端與一輸出端，該輸入端可與該第一光纖熔接， 該輸出、可與該苐二光纖相溶接；再縮減該光纖光柵之至 少一預疋長度部分的纖殼厚度，使形成至少一具有一預定 濾波直徑之纖殼的遽波光纖，且該滤波直徑相異於該第一 、二直徑，使每一濾波光纖之纖殼模態改變，而使該輸出 源輸出之一光訊號通過該光纖光栅後可被濾除該光訊號之 一預定波長範圍的一不平坦部，使光訊號平坦化。 【實施方式】 本發明之七述以及其他技術内谷、特點與功效，在以 9 1221537 玖、發明說明（4 ) . . - 下配合參考圖式之數較佳實施例的詳細說明中，將可清楚 * 的明白。 長週期光纖光栅的特性之一是容易受外界環境的變化 所衫響’如/皿度、應力、折射率、光纖本身的彎曲形變或 5疋本身結構參數的改變等等；當外界環境或本身結構參數 · 變化時，纖核與纖殼模態感應不同的變量，使其傳播常數 產生不同變里，原相位匹配條件因此將改變，造成穿透光 二 譜的變化。因此，利用外界環境的變化或是本身結構參數 鲁二 的改變將可有效調變長週期光纖光柵穿透光譜之特性。 1〇 對纖核模態而言，⑷（光栅纖核有效折射率） 疋由光纖的結構參數來決定的，例如：纖核半徑，纖核與 纖殼材料的折射率等等。因為纖核模態的光場主要限定於 纖核中的區域，且會在纖殼中快速衰減掉，所以如果纖殼 的半徑比纖核的半徑要大上許多時，纖殼的半徑對⑷ 不曰有明顯的作用，此外’對纖殼模態而言，光場的分布 不只在纖核與纖殼的區域，也少量存在於纖殼外部周圍， ⑩ 纖殼半徑的變化將會改變場的分布與纖核模態的有效折射 _ 率’而隨者的改變’相位匹配條件將使耦合位移 · 至其它的波長。 20 因此，本發明之技術思想，即是利用上述當纖殼半徑 減小時，共振波長將向較長波長的方向位移；而對較大的 光栅週期移動的趨勢將更大，且偏移的量將隨纖殼模態的 階數而定，階數愈高則位移量愈大；而穿透光譜中的損失 峰強度將會因為纖核與纖殼兩模態場的重積分增加而增加 10 1221537 玖、發明說明（5 ) ' ,二:::: ’以此，即可有效使通過之光訊號增益平坦化发明. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a gain flattening filter, and particularly to a gain flattening filter suitable for connecting an erbium-doped fiber amplifier in series to flatten the gain of an optical signal. 5 [Previous technology] An all-optical network (AON) system developed with optical fibers as the backbone can provide high-speed and very large-capacity data transmission requirements. Among them, erbium-doped fiber amplifiers (EDFA) are used in all-optical network systems. One of the most important unit components, but due to the influence of the erbium atomic energy level, the output spectrum of the erbium-doped fiber amplifier will have two uneven peaks, and the amplified optical signal power will also cause the amplified optical signal power. Differences affect the discrimination of optical signals and noise at the receiving end of the communication system, and even misjudgment. Therefore, in order to ensure that the optical power of a multi-channel signal in an optical fiber communication system is kept constant, erbium-doped fiber amplifiers will be used. Output gain flattening is indeed an important issue for the development of fiber optic 15 communications. Long period fiber gratings (LPG Long Period Fiber Gratings) were first proposed by Ashish M. Vengsarkar et al. In 1995, and in 1996 they were separately proposed in terms of band rejection filters, temperature sensing and gain flattened fiber amplifier gain. Research is one of the fastest-growing optical passive components in recent years; the long-period fiber grating can lighten the fundamental mode in the fiber core to the forward-propagating fiber-shell mode (Cladding mode). When these modes propagate along the axial direction of the optical fiber, they will be rapidly attenuated due to scattering or absorption caused by the interface between the fiber shell and a medium with a relatively low refractive index (such as air) or bending of the optical fiber, resulting in a long period. Fiber gratings penetrate light 7 1221537 玖, invention description C2) Several loss peaks (resonance wavelengths) appear in the spectrum (as shown in the first figure), so as long as the loss peaks can be properly adjusted, the deduction can be eliminated. The uneven gain portion of the fiber achieves the goal of gain flattening. 5 10 Generally, when changing the period and intensity of the loss peak in the transmission spectrum by changing the period of the long-period fiber grating, there is a problem that the modulation size is not easy to control. Therefore, how to accurately change the period of the long-period fiber grating to Adjusting the position and intensity of the loss peak in the output spectrum, and realizing the technique of flattening the gain of the slope-doped fiber amplifier to the optical communication industry is the goal of the current industry and academia. [Summary of the Invention] Therefore, the primary object of the present invention is to provide a gain flattening filter with a long period fiber grating to flatten the passing optical signal according to a set gain. In addition, another object of the present invention is to provide a manufacturing method of a gain flat filter with a long period of 15 fiber gratings, so as to accurately and mass write the period of a long period fiber grating to achieve the goal of commercialized mass production. Therefore, a gain flat filter and a wave filter with a long period fiber grating of the present invention are fused to a first optical fiber having a fiber housing with a first diameter and a second optical fiber having a fiber housing with a second diameter. In the meantime, the other end of the first optical fiber phase 20 is fused to the gain flat filter in series with an output source capable of outputting an optical signal, and the second optical fiber is opposite to the one connected to the gain flat filter. The other end is connected in series with an optical signal amplifier. The gain-flattening filter includes a fiber grating having an opposite input end and an output end, the input end is fused to the first optical fiber, and the output end is connected to the second Fiber phase 8 发明, description of the invention (3. :) Fusion splicing. It is characterized in that the fiber grating has a light-shearing period that is much longer than the wavelength of light. The filter fiber includes at least a fiber housing with a predetermined filter diameter, and each filter diameter is different from the first and second diameters. The mode of a fiber shell of a wave fiber is modulated, so that the output signal—the optical signal can pass through the fiber grating—and can be divided, except for the optical signal—an uneven portion of a predetermined wavelength range, so that the optical signal is flat. Into. 10 15 20 Furthermore, a method for manufacturing a gain flattened waver with a long-period fiber grating of the present invention is to manufacture a second fiber with a first diameter and a second fiber with a first diameter. The gain flattening filter between the second optical fiber of the shell, the other end of the first optical fiber is opposite to the fusion flattening filter, and the other end is connected in series with an output source capable of outputting an optical signal, and the second optical fiber is opposite to The other end of the fusion-flattening filter is connected in series with an optical signal amplifier. The manufacturing method is to first write an optical fiber into a fiber grating with a grating period, and the fiber grating has an opposite input end and An output end, the input end can be fused with the first optical fiber, and the output can be fused with the second optical fiber; and the thickness of the fiber shell of at least a pre-length of the fiber grating is reduced, so that at least one Chirped wave fiber with a predetermined filter diameter of the fiber shell, and the filter diameter is different from the first and second diameters, so that the fiber shell mode of each filter fiber is changed, and one of the output sources is output After the signal through the optical fiber grating can be filtered out without a flat portion of a predetermined wavelength range of the optical signal, the optical signal is flattened. [Embodiment] The seventh description of the present invention and other technical inner valleys, features, and effects are described in detail in the detailed description of the preferred embodiment with reference to the number 9 1221537 玖, invention description (4).- Be clear * understandable. One of the characteristics of long-period fiber gratings is that they are susceptible to changes in the external environment, such as / degree, stress, refractive index, bending deformation of the fiber itself, or changes in the structural parameters of the fiber, etc .; when the external environment or itself When the structural parameters change, the core and fiber modals induce different variables, which cause their propagation constants to change differently. The original phase matching conditions will therefore change, causing a change in the transmitted light second spectrum. Therefore, the use of changes in the external environment or changes in its own structural parameters can effectively tune the characteristics of the transmission spectrum of long-period fiber gratings. 10 For the core mode, ⑷ (the effective index of the grating core) 疋 is determined by the structural parameters of the fiber, such as the core radius, the refractive index of the core and the shell material, and so on. Because the core modal light field is mainly confined to the area in the core and will rapidly decay in the fiber shell, if the radius of the fiber shell is much larger than the radius of the fiber core, the radius of the fiber shell confronts Not only does it have a significant effect, but also for the fiber shell mode, the distribution of the light field is not only in the area of the fiber core and the fiber shell, but also exists in a small amount around the outside of the fiber shell. 的 Changes in the fiber shell radius will change the field The distribution of the fiber and the effective refractive index of the core mode, and changing the phase matching conditions will shift the coupling to other wavelengths. 20 Therefore, the technical idea of the present invention is to use the above-mentioned when the fiber shell radius is reduced, the resonance wavelength will be shifted to a longer wavelength direction; and the trend of larger grating period movement will be greater, and the amount of shift Will depend on the order of the fiber shell mode, the higher the order, the greater the displacement; and the intensity of the loss peak in the transmission spectrum will increase by 10 due to the increase of the reintegration of the two modal fields of the fiber core and the fiber shell. 1221537 发明, description of the invention (5) ', 2: ::::' This can effectively flatten the gain of the light signal passing through
參閱第二圖，本發明一種具有長週期光纖光柵之增益 平坦濾波器1，是熔接於二光纖300、300,之間，本例是 使用市售FiberCore PS1500，纖核直徑9// m，纖殼直徑 125/zm，其中之一光纖300相反於熔接該增益平坦濾波 器1之一端是與一可輸出一光訊號之輸出源100相串接， 另一光纖300,相反於熔接該增益平坦濾波器1之一端是與 一摻铒光纖放大器（EDFA) 200相串接。 該增益平坦濾、波器1包含一具有相反之一輸入端Π1 與一輸出端112之光纖光栅11，該輸入端ill、輸入端 112分別與上述光纖300、300,相熔接。Referring to the second figure, a gain flat filter 1 with a long period fiber grating according to the present invention is fused between two optical fibers 300 and 300. In this example, a commercially available FiberCore PS1500 is used, and the core diameter is 9 // m. The shell diameter is 125 / zm. One of the optical fibers 300 is opposite to fusing the gain flat filter. One end is connected in series with an output source 100 that can output an optical signal. The other fiber 300 is opposite to fusing the gain flat filter. One end of the device 1 is connected in series with an erbium-doped fiber amplifier (EDFA) 200. The gain flat filter and wave filter 1 includes a fiber grating 11 having an opposite input end Π1 and an output end 112, and the input end ill and the input end 112 are fused with the optical fibers 300 and 300, respectively.
該光纖光柵11是以市售FiberCorePS1500,纖核直 徑9# m，纖殼直徑125/zm之光纖寫製，使其具有一遠 大於光之波長的光柵週期（本例是373 //m)，而可有效調 15 變光訊號穿透光譜之特性。該光纖光柵11包含一具有一 預定濾波直徑之纖殼的濾波光纖113，該濾波光纖113是 以餘刻方式縮減其纖殼厚度，而使濾波直徑小於該等光纖 300、300’之直徑，在本例中是以長度4公分且濾波直徑 縮減至116 μ m之濾波光纖113，而使該濾波光纖113之 20 纖殼模態被調變，使其穿透光譜如第三圖所示，而使該輸 出源100輸出之光訊號通過該光纖光栅u後，可被濾除 如第四圖所示，摻铒光纖放大器2〇〇在l52〇nm〜l59〇nm 之波長範圍下’出現於波長約1530nm的一突起峰，使光 訊號在1530nm處被增益平坦化。 11 1221537The fiber grating 11 is written using a commercially available FiberCorePS1500 fiber with a core diameter of 9 # m and a fiber shell diameter of 125 / zm, so that it has a grating period much longer than the wavelength of light (in this example, 373 // m), And it can effectively adjust the characteristics of the optical signal transmission spectrum. The fiber grating 11 includes a filter fiber 113 having a fiber case with a predetermined filter diameter. The filter fiber 113 reduces the thickness of the fiber case in a manner such that the filter diameter is smaller than the diameter of the fibers 300, 300 '. In this example, a filter fiber 113 with a length of 4 cm and a filter diameter reduced to 116 μm is used to modulate the 20 fiber shell mode of the filter fiber 113 so that its transmission spectrum is shown in the third figure, and After passing the optical signal output by the output source 100 through the fiber grating u, it can be filtered out. As shown in the fourth figure, the erbium-doped fiber amplifier 200 appears at a wavelength in a wavelength range of 1520 nm to 1590 nm. A raised peak at about 1530nm flattens the optical signal at 1530nm. 11 1221537
參閱第五圖，本發明一種具有長週期光纖光栅之增益 平坦濾波器Γ，是與上例相似，其不同處僅在於該增益平 坦濾波器r之光纖光柵2，包含多數分別具有預定濾波直 徑之纖殼的濾波光纖21、22、23 (在本例中以三濾波光 5 纖為例說明），該些濾波光纖21、22、23是分別以蝕刻方 式縮減其纖殼厚度，而使濾波直徑小於該等光纖300、 300’之直徑。該些遽波光纖21、22、23長度均為4cm， 直徑是分別縮減為116、102、100/zm，而使該等濾波光 纖21、22、23之纖殼模態被調變，呈現如第六圖所示之 0 穿透光譜圖，而使輸出源1〇〇輸出之光訊號通過該光纖光 柵2後，可被濾除如第四圖所示之摻铒光纖在 1520nm〜1590nm之波長範圍下，分別出現於波長約 1530nm的一突起峰，及I540nm、1560nm的二損失峰， 使光訊號平坦化，呈現如第七圖所示之穿透光譜圖。 5 上述本發明具有長週期光識光栅之增益平坦濾波器1 分別是以串接單一濾波光纖113、及三纖殼直徑互異 之濾波光纖21、22、23為例說明，當然，由本發明之理 ’依據可知’實際串接滤波光纖之數目、每一濾波光纖之 纖设直徑、長度等等，均需視實際串接之光學訊號放大器 〇 (本例是以摻铒光纖放大器為例）的光學特性，以及所須 專送光訊號時之需要而有所不同，在此不再一 一詳加舉例 說明。 而’製作上述本發明具有長週期光纖光柵之增益平坦 濾波器之製造方法的一第_較佳實施例，是用於製造上述 12 1221537 玫、發明_明（7 ) :二 ； "..........................^ 具有單一濾波光纖113之長週期光纖光栅u的增益平坦 濾波器1。 參閱第八圖，該製造方法3是先進行步驟31以光罩 法寫製長週期光纖光柵11，請同時參閱第九圖，本例以 5 市售FiberCore PS1500 ’纖核直徑9" m，纖殼直徑125/zReferring to the fifth figure, a gain flat filter Γ with a long period fiber grating according to the present invention is similar to the above example, except that the fiber grating 2 with the gain flat filter r includes most of the fiber gratings 2 each having a predetermined filtering diameter. Fiber filter fibers 21, 22, and 23 (in this example, three filter fibers and 5 fibers are used as an example). These filter fibers 21, 22, and 23 are etched to reduce the thickness of the fiber cover to make the filter diameter. Smaller than the diameter of these fibers 300, 300 '. The chirped wave fibers 21, 22, and 23 are 4 cm in length and reduced in diameter to 116, 102, and 100 / zm, respectively, so that the fiber shell modalities of the filter fibers 21, 22, and 23 are modulated, showing as The 0 transmission spectrum shown in the sixth figure, after the optical signal output from the output source 100 passes through the fiber grating 2, can be filtered out the wavelength of 1520nm ~ 1590nm of the erbium-doped fiber shown in the fourth figure In the range, one protrusion peak at a wavelength of about 1530 nm and two loss peaks at I540 nm and 1560 nm appear respectively, so that the optical signal is flattened, and the transmission spectrum shown in the seventh figure is presented. 5 The above-mentioned gain flat filter having a long period optical grating according to the present invention 1 is described by taking a series connection of a single filter fiber 113 and three filter fibers 21, 22, and 23 with mutually different diameters as examples. Of course, the present invention The rationale is based on the number of actual filter fibers connected in series, the fiber diameter and length of each filter fiber, etc., depending on the actual optical signal amplifier connected in series. (This example uses an erbium-doped fiber amplifier as an example) The optical characteristics are different, as well as the needs when the optical signal must be sent exclusively. I will not give detailed examples here. And a first preferred embodiment of the manufacturing method of the above-mentioned manufacturing method of the gain flat filter with a long period fiber grating of the present invention is used to manufacture the above 12 1221537, invention_ming (7): two; " .. ...... ^ Gain flat filter 1 for a long period fiber grating u with a single filter fiber 113. Referring to the eighth figure, the manufacturing method 3 is first performed in step 31 to write a long-period fiber grating 11 in a photomask method. Please refer to the ninth figure at the same time. In this example, FiberCore PS1500 'fiber core diameter 9 " m Shell diameter 125 / z
m之光纖，經1500 psi高壓載氫約一週，並利用 200mJ/cm2之KrF準分子雷射作為曝照光纖的光源，以振 幅光罩週期為375 /zm，長度為4cm，照射25秒，再以 150 C回火24小時，逐出光纖中的重氳及氫，而寫製成光 10 柵週期為375 /z m之長週期光纖光柵11。 接著，再以步驟32縮減該長週期光纖光栅u之部分 的纖殼厚度’在本例中是其浸置於重量百分比濃度為2〇0/〇 的氫氟酸溶液中蝕刻其纖殼，使其形成纖殼直徑U6//m 之攄波光纖113，即完成上述具有長週期光纖光柵η之 15 增益平坦濾波器1的製備。m fiber, subjected to 1500 psi high-pressure hydrogen carrying for about one week, and using 200mJ / cm2 KrF excimer laser as the light source for the fiber exposure, with an amplitude mask period of 375 / zm, a length of 4cm, and irradiation for 25 seconds, and then Tempering at 150 C for 24 hours, the weight of the fiber and hydrogen in the fiber was expelled, and a long-period fiber grating 11 with a grid period of 375 / zm was written. Then, in step 32, the thickness of the fiber shell of the portion of the long-period fiber grating u is reduced. In this example, the fiber shell is immersed in a hydrofluoric acid solution with a concentration of 200% by weight to etch the fiber shell so that It forms a chirped wave fiber 113 with a fiber shell diameter of U6 // m, that is, the above-mentioned preparation of the 15-gain flat filter 1 with a long period fiber grating η is completed.
當然’上述縮減纖殼厚度之方式，當然不限於以氫氟 酸溶液敍刻進行，以酸、或鹼性溶液或其他化學溶液均為 可行的方法；同時，待商業化量產時機成熟，也可以直接 生產纖殼直徑為116/zm的光纖，再寫製預定週期後，兩 20 端再熔接寫製相同週期之標準光纖（即纖核直徑9/ζχπ， 纖殼直徑125/z m之光纖），製成光纖光栅；由於此些製 程方式均可依據本發明所舉之實際製程所簡易推知，故在 此不再一一舉例。 參閱第十圖，本發明具有長週期光纖光柵之增益平坦 13 1221537 玖、發明說明（S ) 遽波器之製造方法的一第二較佳實施例，是用於製造上述 具有三濾波光纖21、22、23之長週期光纖光柵2的增益 平坦濾波器Γ。 該製造方法4例與該第一較佳實施例相似，是先進行 5 步驟41以光罩法寫製長週期光纖光柵2,請同時參閱第 九圖，本例以市售FiberCore pS1500，纖核直徑9//m， 纖设直住125 // m之光纖，經1500 pSi高壓載氫約一週， 並利用200mJ/Cm2之KrF準分子雷射作為曝照光纖的光 源，以振幅光罩週期為375 # m，長度為4cm，照射預定 10時間，再以150 C回火24小時，逐出光纖中的重氫及氫 ，寫製成該光柵週期為375 /zm之長週期光纖光栅2。 接著，再以步驟42依序縮減該長週期光纖光栅2之 三預定長度部分的纖殼厚度使其分別形成該濾波光纖21 、22、23 ;在本例中是先將其中一端部約數公分長先用防 15腐蝕護具套覆，再以另一端部不接觸溶液地浸置於重量百 分比濃度為20〇/〇的氫氟酸溶液中钱刻其纖殼一預定時間， 使其纖殼直116//m成為一濾波光纖21，接著上提4 公分，繼續餘刻至剩下部分的纖殼直徑至1〇2//m成為另 一濾波光纖22 ;接著再繼續上提4公分，使剩下部分之 20纖殼直徑钱刻至100_成為又一滤波光纖^，使形成具 有三纖殼錄互異之滤波光纖21、22、23的長週期光纖 光柵2，完成本發明具有長週期光纖光拇2之增益平坦遽 波器Γ的製備。 w S然，上述縮減長週期光纖光栅2之三預定長度部分 14 砍、發明_( 9) ，纖殼厚度之方式，當料限於以氫氣酸溶液餘刻方式 仃，以酸、或驗性溶液或其他化學溶液均為可行的 此外，韻刻的方式也不限於上述以一端部浸置於溶液中， 2序上提_出不同纖般厚度的缝光纖，也可以例如製 乍不同長度之護套，套覆後整根浸入溶液中，再依需求餘 刻出不同纖殼厚度之滤波光纖；由於此種钱刻的過::已 為多數業界習常慣用，方法種類均不勝牧舉故在此不 一一舉例。 再 參閱第十一圖，本發明具有長週期光纖光栅之增益平 1〇 坦濾波器之製造方法的一第三較佳實施例，是與上述第二 較佳實施例相似，用來製造具有三濾波光纖21、22、U 之長週期光纖光柵2的增益平坦濾波器Γ。 該製k方法5首先以步驟51將三光纖分別以光罩法 寫製成具有相同之光柵週期，本例同樣地以市售 15 FiberCore PS1500，纖核直徑 9/zm，纖殼直徑 i25/zm 之 光纖’經1500 psi南壓載氫約一週，並利用2〇〇raJ/cm2 之KrF準分子雷射作為曝照光纖的光源，以振幅光罩週期 為375 /z m，長度為4cm，照射預定時間，再以i5〇°c回 火24小時，逐出光纖中的重氫及氫，寫製成光柵週期為 2〇 375//m之長週期光纖光栅。 再以步驟52分別縮減該些長週期光纖光柵之纖殼直 徑，使其形成多數分別具有不同濾波直徑之纖殼的濾波光 纖；在本例中是將三光纖光栅分別蝕刻其纖殼厚度，使其 形成纖殼直徑分別為116/zm、102//in、100//m之三濾 15 5 坎、發明p兌明（1❸） 波光纖21、22、23。 最後以步驟53將該三濾波光纖21、22、23依序熔接 成該長週期光纖光柵2,完成具有長週期光纖光栅2之增 益平坦濾波器1，的製備。 曰 10 當然，本例待商業化量產時機成熟後，也可以直接生 產纖设直輕分別為HMm、l〇2/zm、100/zm的光纖， 刀別寫製預定週期後’再依序料成長週期光纖光拇，以 更符合篁產考量；由於此些製程方式均可依據本發明所舉 之只際製程所簡易推知，故在此不再多加贅述。 15 在此要特別說明的是，本發明可以先針對所有市售的 光纖，分別建立其纖殼直徑與其穿透光譜中損失峰位置之 貝料庫，以供長週期光纖光柵11、2的製備與研究。舉例 來5兄’可將長週期光纖光柵置於2〇%之氫氟酸溶液中蝕 刻纖设直徑，蝕刻時間以1小時為一單位，然後將其取出 、另未經餘刻之光纖置於C.C.D.(color camera digital) 下對比里測其直徑變化並利用光譜分析儀測其穿透光譜， 20Of course, the above-mentioned way to reduce the thickness of the fiber shell is of course not limited to the use of hydrofluoric acid solution. It is feasible to use acid, alkaline solution or other chemical solutions. At the same time, when the commercial production volume is mature, It can directly produce the fiber with a fiber shell diameter of 116 / zm. After the predetermined period is written, the two 20 ends are spliced to write the standard fiber with the same cycle (ie, the fiber with a core diameter of 9 / ζχπ and a fiber shell diameter of 125 / zm). Fiber gratings are made; since these manufacturing methods can be easily inferred based on the actual manufacturing process provided by the present invention, no examples will be given here. Referring to the tenth figure, the gain of the present invention having a long period fiber grating is flat 13 1221537 玖, a second preferred embodiment of the manufacturing method of the (S) chirped waver is used for manufacturing the above-mentioned three-filter fiber 21, Gain flattening filter Γ of the long period fiber grating 2 of 22 and 23. The 4 examples of the manufacturing method are similar to the first preferred embodiment. First, 5 steps 41 are performed to write a long-period fiber grating 2 using a photomask method. Please also refer to the ninth figure. In this example, a commercially available FiberCore pS1500, fiber core is used. A fiber with a diameter of 9 // m and a straight line of 125 // m was passed through a high-pressure hydrogen carrying of 1500 pSi for about a week, and a KrF excimer laser of 200mJ / Cm2 was used as the light source for the fiber exposure. The amplitude mask period was 375 # m, 4 cm in length, irradiated for a predetermined time of 10, and then tempered at 150 C for 24 hours to expel the heavy hydrogen and hydrogen in the fiber, and write a long-period fiber grating 2 with a grating period of 375 / zm. Then, in step 42, the thickness of the fiber shell of the predetermined length portion of the three-period fiber grating 2 is sequentially reduced to form the filter fibers 21, 22, and 23, respectively; in this example, one end is first lengthened by a few centimeters. First cover with 15 anti-corrosion protective gear, and then immerse the other end without contacting the solution in a hydrofluoric acid solution with a weight percentage of 20/0 and engraving its fibrous shell for a predetermined time to make the fibrous shell straight. 116 // m becomes a filter fiber 21, and then it is raised by 4 cm, and the remaining part of the fiber shell diameter is 102/2 / m to become another filter fiber 22; then it is further raised by 4 cm, so that The remaining 20 fiber shell diameter is engraved to 100_ to become another filtering optical fiber ^, so that a long-period fiber grating 2 with three fiber-optic fiber filters 21, 22, and 23 is formed, and the present invention has a long period Preparation of gain flattened wave waver Γ of optical fiber thumb 2. However, the above-mentioned method of reducing the predetermined length of the long-period fiber grating 2 tertiary part 14 was invented, (9), the thickness of the fiber shell, and the material is limited to the hydrogen acid solution, the acid, or the test solution. In addition, other chemical solutions are feasible. In addition, the method of rhyme carving is not limited to the above-mentioned one end immersed in the solution, and the second order lifts out the slit fiber with different fiber thickness. The whole fiber is immersed in the solution after being covered, and then the filter fiber with different fiber shell thickness is engraved according to the requirements. Because this kind of money has been engraved :: It is customary in most industries, and the types of methods are inexorable. This is not an example. Referring to FIG. 11 again, a third preferred embodiment of the manufacturing method of the gain flat 10-tan filter with a long period fiber grating of the present invention is similar to the second preferred embodiment described above, and is used for manufacturing The gain flat filter Γ of the long-period fiber grating 2 that filters the optical fibers 21, 22, and U. In the manufacturing method 5, firstly, the three optical fibers are respectively written in a mask method to have the same grating period in step 51. In this example, 15 FiberCore PS1500 with a core diameter of 9 / zm and a fiber shell diameter of i25 / zm are also commercially available. The optical fiber 'passes 1500 psi south of ballast hydrogen for about a week, and uses a KrF excimer laser of 200raJ / cm2 as the light source for the optical fiber. The amplitude mask period is 375 / zm and the length is 4cm. Time, tempering at i50 ° C for 24 hours, expelling the heavy hydrogen and hydrogen in the optical fiber, and writing into a long-period fiber grating with a grating period of 2075 // m. In step 52, the fiber shell diameters of the long-period fiber gratings are reduced to form filter fibers that have fiber shells with different filter diameters. In this example, the three fiber gratings are etched into their fiber shell thicknesses so that The formation of the three fiber filters with diameters of 116 / zm, 102 / in, and 100 // m is 15 5 Km, and the invention discloses p-bright (1❸) wave optical fibers 21, 22, and 23. Finally, the three filtering fibers 21, 22, and 23 are sequentially fused to the long-period fiber grating 2 in step 53 to complete the preparation of the gain flat filter 1 having the long-period fiber grating 2. Day 10 Of course, after the commercial mass production time is ripe, this example can also directly produce optical fibers with HMm, 102 / zm, and 100 / zm, respectively. After the predetermined period is written, the order will be followed. It is expected that the optical fiber of the optical fiber growth cycle is more in line with production considerations. Since these manufacturing methods can be easily inferred based on the only manufacturing process provided by the present invention, it will not be repeated here. 15 It should be particularly noted here that the present invention can first establish a shell material library for the diameter of the fiber shell and the position of the loss peak in its transmission spectrum for all commercially available optical fibers, for the preparation of long-period fiber gratings 11, 2 And research. For example, you can put a long-period fiber grating in a 20% hydrofluoric acid solution to etch the fiber diameter. The etching time is 1 hour, and then take it out. CCD (color camera digital): measure the change in diameter and compare the transmission spectrum with a spectrum analyzer. 20
以建立如第十二圖所示之不同纖殼直徑下的穿透光譜圖之 關係圖’第十三圖蝕刻時間與纖殼直徑變化之關係圖，及 第十四圖所量測到之光纖直徑與長週期光纖光柵穿透光譜 中各損失峰位置之關係圖，而以此些數據、圖表將可精確 實現光纖放大器所需長週期光纖光柵之直徑與損失峰 位置之參考資料庫，並可實際量化生產需之長週期光纖光 此外’上述較佳實施例之說明雖然是將本發明之應用 16 1221537In order to establish the relationship between the transmission spectrum of different fiber shell diameters as shown in Figure 12, the relationship between the etching time and the change in fiber shell diameter in Figure 13 and the optical fiber measured in Figure 14 The relationship between the diameter and the position of each loss peak in the transmission spectrum of the long-period fiber grating. With these data and charts, a reference database of the diameter and position of the peak of the long-period fiber grating required by the fiber amplifier can be accurately realized. Long-period fiber optic light required for actual quantification production In addition, although the description of the above-mentioned preferred embodiment is an application of the present invention 16 1221537
侷限在摻铒光纖放大器、長週期光纖光栅之直徑在n6/z Hi、l〇2#m、100#m，且使光訊號平坦化之波長範圍為 152〇nm〜1590nm之内，但是由第十三、十五圖之實驗結 果可輕易推知，本發明並不限於應用在摻铒光纖放大器， 5 且長週期光纖光栅的直徑範圍，及使光訊號平坦化之波長 範圍並不限於上述，而可應用於一般需要增益平坦光訊號 之光兀件上，並延伸長週期光纖光柵的直徑範圍介於纖核 與包覆纖核之最大纖殼的一外表面之間，且光訊號平坦化 之波長範圍為1200nm〜1600nm之内，甚至，以此實驗基 1〇礎向外延伸，則可以依實際光元件平坦化光波長範圍之需 要而相對應地串接多種不同直徑之長週期光纖光柵，以 達到增盈平坦光訊號之目的，由於此種應用，凡熟習此項 技藝人士皆可輕易推知，且光元件種類眾多、其應用之波 長範圍亦廣，故不再多加--舉例說明。。 15 歸納上述’本發明具有長週期光纖光柵之增益平坦濾 波益及其製造方法，是以光纖纖殼之半徑減小時，共振波 長將向較長波長的方向位移；而對較大的光柵週期移動的 趨勢將更大’且偏移的量將隨纖殼模態的階數而定，階數 t南則位移量愈大；而穿透光譜中的損失峰強度將會因為 2〇 、纖核與纖殼兩模態場的重積分增加而增加為技術思想，並 以钱刻方式精確改變纖殼直徑，使增益平坦濾、波器之光纖 光桃0 3多數分別具有預定濾波直徑之纖殼的濾波光纖， @使該輪出源輸出之光訊號通過該光纖光柵後，可被遽除 預疋波長範圍的突起峰或損失峰，而使光訊號平坦化，而 17 1221537 玖、發明說明（12) 可確實改善一般改變長週期光纖光柵之週期來調變其穿透 光譜中損失峰之位置與強度時，出現調變大小不易控制的 問題，且可在長週期光纖光柵寫製後有效且精確調變損失 峰之位置與強度，損失峰之偏移可達290nm以上（LP02/ 5 直徑36//m)，損失峰強度也可增加5倍以上（LP02/直徑 36#111)，而確實達到本發明之目的。 惟以上所述者，僅為本發明之較佳實施例而已，當不 能以此限定本發明實施之範圍，即大凡依本發明申請專利 範圍及發明說明書内容所作之簡單的等效變化與修飾，皆 10 應仍屬本發明專利涵蓋之範圍内。 【圖式簡單說明】 第一圖是長週期光纖光栅之穿透光譜圖； 第二圖是本發明具有長週期光纖光柵之增益平坦濾波 器之一第一較佳實施例的示意圖，並說明其長週期光纖光 15 栅具有單一濾波光纖； 第三圖是第二圖之長週期濾波光纖之穿透光譜圖，並 說明其在波長約1530nm有一損失峰； 第四圖是摻铒光纖放大器200在1520nm〜1590nm之 波長範圍下之一穿透光譜圖，並說明波長約1530nm出現 20 一突起峰，及1540nm、1560nm出現二損失峰； 第五圖是本發明另一具有長週期光纖光柵之增益平坦 濾波器之一第二較佳實施例的示意圖，並說明其長週期光 纖光柵具有三濾波光纖； 第六圖是第五圖之長週期濾波光纖之穿透光譜圖，並 18 1221537 玖、發讎明（13 ) 說明其在波長約1530nm有一損失峰，及1540nm、 1560nm的二突起峰； 第七圖是串接第五圖所示之增益平坦濾波器後之一穿 透光譜圖，並說明摻餌光纖放大器放大之光訊號被增益平 5 坦之結果； 第八圖是本發明具有長週期光纖光柵之增益平坦濾波 器之製造方法之一第一較佳實施例的流程圖； 第九圖是說明本發明具有長週期光纖光柵之增益平坦 濾波器之製造方法時，寫製長週期光纖光柵之一示意圖； 10 第十圖是本發明具有長週期光纖光柵之增益平坦濾波 器之製造方法之一第二較佳實施例的流程圖； 第十一圖是本發明具有長週期光纖光柵之增益平坦濾 波器之製造方法之一第三較佳實施例的流程圖； 第十二圖是一實驗結果關係圖，說明不同纖殼直徑之 15 濾波光纖的穿透光譜； 第十三圖是一實驗結果關係圖，說明蝕刻濾波光纖時 ，蝕刻時間與纖殼直徑變化之關係；及 第十四圖是一實驗結果關係圖，說明所量測到之光纖 直徑與長週期光纖光柵穿透光譜中各損失峰位置之關係。 19 20 1221537 玖、發朋說明（14 ) 【圖式之主要元件代表符號簡單說明】 100 輸出源 3…* •製造方法 200 摻铒光纖放大器 31… •步驟 300、300’ 光纖 32… •步驟 卜Γ 增益平坦濾波器 4…… •製造方法 11 長週期光纖光栅 41 · · >步驟 111 輸入端 42 · · · •步驟 112 輸出端 5 * ^ * •製造方法 113 濾波光纖 51… •步驟 2 長週期光纖光柵 52… •步驟 21 濾波光纖 53 · * * •步驟 22 濾波光纖 23 渡波光纖 20It is limited to erbium-doped fiber amplifiers, long-period fiber gratings with diameters of n6 / z Hi, 102 # m, and 100 # m, and the wavelength range for flattening optical signals is within the range of 1520nm to 1590nm. The experimental results of Figures 13 and 15 can be easily inferred that the present invention is not limited to the application to erbium-doped fiber amplifiers, and the diameter range of long-period fiber gratings, and the wavelength range for flattening optical signals are not limited to the above, and Can be applied to optical components that generally require a flat optical signal, and extend the diameter of a long-period fiber grating between the core and an outer surface of the largest fiber shell covering the core, and the optical signal is flattened. The wavelength range is from 1200nm to 1600nm, and even if this experimental base is extended outwardly, a variety of long-period fiber gratings with different diameters can be connected in series according to the needs of the actual optical element to flatten the light wavelength range. In order to achieve the purpose of increasing the flat optical signal, due to this application, anyone skilled in this art can easily infer that there are many types of optical components and a wide range of wavelengths, so it is not necessary to add more- Instructions. . 15 In summary, the above-mentioned gain flat filtering benefit of the present invention having a long period fiber grating and its manufacturing method are such that when the radius of the fiber shell decreases, the resonance wavelength will be shifted to a longer wavelength; and the larger grating period will be shifted. The trend will be larger 'and the amount of offset will depend on the order of the fiber shell mode, the greater the order t, the greater the amount of displacement; and the loss peak intensity in the transmission spectrum will be It is a technical idea to increase the reintegration of the two modal fields with the fiber shell, and accurately change the fiber shell diameter in a engraved manner, so that the gain is flat, and the fiber optic fiber of the wave filter is mostly a fiber shell with a predetermined filtering diameter. The filtering optical fiber @ makes the light signal output from the round source pass through the fiber grating, and can be eliminated by the peak or loss peak of the pre-wavelength range, and the optical signal is flattened. 17 1221537 发明, description of the invention ( 12) It can really improve that when the period of the long-period fiber grating is changed to adjust the position and intensity of the loss peak in the transmission spectrum, the problem that the modulation size is difficult to control, and can be improved after the long-period fiber grating is written. The position and intensity of the loss peak can be adjusted efficiently and accurately. The shift of the loss peak can reach more than 290nm (LP02 / 5 diameter 36 // m), and the intensity of the loss peak can also be increased by more than 5 times (LP02 / diameter 36 # 111). The purpose of the present invention is achieved. However, the above are only the preferred embodiments of the present invention. When the scope of implementation of the present invention cannot be limited by this, that is, the simple equivalent changes and modifications made according to the scope of the patent application and the content of the invention specification, Both 10 should still fall within the scope of the invention patent. [Schematic description] The first figure is a transmission spectrum of a long-period fiber grating. The second diagram is a schematic diagram of a first preferred embodiment of a gain flattening filter with a long-period fiber grating of the present invention, and illustrates the same. The 15-grid of the long-period fiber optic fiber has a single filter fiber. The third figure is the transmission spectrum of the long-period filter fiber of the second figure, and it shows a loss peak at a wavelength of about 1530nm. The fourth figure is the erbium-doped fiber amplifier 200 at One transmission spectrum in the wavelength range of 1520nm ~ 1590nm, and shows that a peak of 20 appears at a wavelength of about 1530nm, and two loss peaks appear at 1540nm and 1560nm. The fifth figure is another gain flat fiber grating with a long period of the present invention. A schematic diagram of a second preferred embodiment of a filter and illustrating that its long-period fiber grating has three filtering fibers; the sixth figure is the transmission spectrum of the long-period filtering fiber of the fifth figure, and 18 1221537 玖, 雠Ming (13) shows that it has a loss peak at a wavelength of about 1530 nm, and two protrusion peaks at 1540 nm and 1560 nm; the seventh figure is one of the gain flattening filters connected in series as shown in the fifth figure. Spectral diagram and the results of flattening the optical signal amplified by the bait-doped fiber amplifier. The eighth diagram is the flow of the first preferred embodiment of the method for manufacturing a gain flat filter with a long period fiber grating of the present invention. The ninth figure is a schematic diagram of a long-period fiber grating with a long-period fiber grating when describing the manufacturing method of the gain-flat filter with a long-period fiber grating according to the present invention. Is a flowchart of a second preferred embodiment of a manufacturing method of a filter; FIG. 11 is a flowchart of a third preferred embodiment of a manufacturing method of a gain flat filter with a long period fiber grating of the present invention; The second figure is a relationship diagram of experimental results, illustrating the transmission spectrum of 15 filter fibers with different fiber shell diameters; the thirteenth figure is a relationship diagram of experimental results, illustrating the relationship between the etching time and the change in fiber diameter when the filter fiber is etched; And Figure 14 is a graph of experimental results, illustrating the measured fiber diameter and the position of each loss peak in the long-period fiber grating transmission spectrum. relationship. 19 20 1221537 说明, Fapon description (14) [Simplified description of the main components of the diagram] 100 output source 3 ... * • Manufacturing method 200 Erbium-doped fiber amplifier 31 ... • Step 300, 300 'fiber 32 ... • Step b Γ Gain flat filter 4 ... • Manufacturing method 11 Long period fiber grating 41 · > Step 111 Input 42 · · · • Step 112 Output 5 * ^ * • Manufacturing method 113 Filter fiber 51 ... • Step 2 Long Periodic Fiber Grating 52 ... • Step 21 Filtering Fiber 53 · * * • Step 22 Filtering Fiber 23 Crossing Wave Fiber 20