TW499565B - High stability intensity-based optical fiber sensors - Google Patents
High stability intensity-based optical fiber sensors Download PDFInfo
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499565 五、發明說明(1) 發明背景 光纖感測裔具備的諸多^ ^ ^ ^ ^ ^ ^ 快、體積小、重量輕、耐:=敏度南、反應速度 正常工作,同時利用光敏::…使其能在危險環境中 + π # ^ ,sp。s Z纖傳輸訊號達到遠端遙測之目的。 由於光纖感測态具有不辱φ其 Μ:田仏to A 4人 又電磁场干擾和多點量測…等特 性’:此相當。7適合於多點式物理與生化參數的量測。 ^ , . ^ ^^ tter和H〇cker發表光纖應變感測器 m ΐt:用於光纖智慧型結構便成為世界研究 、展趨勢。近年來,由於光纖光栅開發成功,丨不僅具有 一般光纖感測器的優點,更在多點量測(Multiplexing) 2有極大優勢埋入型光纖光栅感測器、光纖光柵多參數 量測感測器等皆是世界研究發展的趨勢。 在強度型光纖感測器的發展上,由於極易受到光源與 環境的影響,因此,可靠度較為使用者質疑。近幾年發展 的相關強度型θ光纖感測器有下列幾種形式。美國專利 5,11 8,9 31號提出以不同光纖光柵所反射相對的微彎曲( Microbending)所引起光強變化作為感測目標,但未提出 以一對光纖光柵達到補償的功能。美國專利4, 7 92, 689號 雖提出參考訊號與感測訊號之間的補償方式,並以特殊染 料(Dye)染色劑偵測生化反應,但由於光譜分光裝置是設 計在接收端上,因此仍無法達到類似光纖光柵多點量測的 簡易功能。美國專利5, 646, 400號提出45。錐形(Tapped) 光纖光栅之光纖漸瞬波場與披覆在光纖光柵上的腐蝕敏感 化合物(Corrosion Sensitive Compound)反應,而達到499565 V. Description of the invention (1) Many backgrounds of fiber optic sensors ^ ^ ^ ^ ^ ^ ^ Fast, small size, light weight, resistant: = sensitivity south, response speed works normally, while using photosensitivity :: ... It can be used in a dangerous environment + π # ^, sp. s Z fiber transmission signals achieve the purpose of remote telemetry. Because the optical fiber sensing state has no shame, its M: Tian Yi to A 4 people, and electromagnetic field interference and multi-point measurement ... etc. characteristics: This is equivalent. 7Suitable for multi-point measurement of physical and biochemical parameters. ^,. ^ ^^ tter and Hocker publish fiber-optic strain sensors m ΐt: For the intelligent structure of optical fiber, it has become a world research and exhibition trend. In recent years, due to the successful development of fiber gratings, not only has the advantages of ordinary fiber sensors, but also has great advantages in multipoint measurement 2 Multiplexed fiber grating sensors, fiber grating multi-parameter measurement sensors Devices and so on are the trends of world research and development. In the development of intensity-type optical fiber sensors, reliability is more questionable by users because it is extremely susceptible to the influence of light sources and the environment. Related intensity type θ fiber sensors developed in recent years have the following forms. U.S. Patent No. 5,11,8,9,31 proposes to use the light intensity change caused by the relative microbending reflected by different fiber gratings as the sensing target, but does not propose a pair of fiber gratings to achieve the compensation function. U.S. Patent No. 4, 7 92, 689 proposes a compensation method between the reference signal and the sensing signal, and uses a special dye (Dye) dye to detect the biochemical reaction, but because the spectroscopic device is designed on the receiving end, so Still can not achieve simple functions like fiber grating multi-point measurement. U.S. Patent 5,646,400 proposes 45. The tapered fiber grating's gradual-instantaneous wave field reacts with the Corrosion Sensitive Compound coated on the fiber grating.
第5頁 499565 五、發明說明(2) 光強度變化’但無法作補償設計,仍然受到環境擾動的影 響。Spillman,W.B·,jr· andL〇rd,J R· [SpiUman, W.B·, Jr· and Lord, J.R·, ”Self_Referencing Multiplexing Technique for Fiber-Optic Intensity Sensors, IEEE, Journal of Lightwave Technology, LTj, pp· 865 - 869, 1 987 ]所提出量測的方法是採用自我 補償式的技術;以兩個偶合器將一個脈衝光波循環分成多 道光波,一道為參考的光波,其他道為感測的光波。兩道 光波之間接上感測器,感測器會因為外在壓力改變,而使 感測光波產生強度變化,藉著參考光波和感測光波的比 值’可以量測外在環境的變化。 發明要旨 本發明主要是要發展一種結構簡單且可靠度高之光纖 光柵感測器,並可避免外在環境對於量測訊號的影響,因 而加強感測器對於篁測目標的準確度。應用此感測器在機 械或建築結構之上,可以做到即時監測及多點量測,有助 於提高結構物之安全性及了解其結構健康狀況,提早做補 強或預防之措施;亦可設計為生化感測器,只要在感测區 鍍上反應介質,使光強度因待測物與反應介質作用而產生 變化,即可達到偵測目的。 發明之詳細說明 光纖光柵感測器主要具備反應速度快、體積小、重量Page 5 499565 V. Description of the invention (2) Changes in light intensity 'but cannot be used for compensation design and are still affected by environmental disturbances. Spillman, WB ·, jr · and Lórd, JR · [SpiUman, WB ·, Jr · and Lord, JR ·, "Self_Referencing Multiplexing Technique for Fiber-Optic Intensity Sensors, IEEE, Journal of Lightwave Technology, LTj, pp · 865 -869, 1 987] The measurement method proposed is a self-compensating technique; a pulsed light wave is cyclically divided into multiple light waves with two couplers, one of which is a reference light wave, and the other is a sensed light wave. Two A sensor is connected between the light waves and the sensor will change the intensity of the sensed light wave due to the change in external pressure. The change of the external environment can be measured by the ratio of the reference light wave and the sensed light wave. The invention is mainly to develop a fiber grating sensor with a simple structure and high reliability, and can avoid the influence of the external environment on the measurement signal, so as to enhance the accuracy of the sensor for the target being measured. Apply this sensing The device can be used for real-time monitoring and multi-point measurement on the mechanical or building structure, which can help improve the safety of the structure and understand its structural health. Do reinforcement or preventive measures; can also be designed as a biochemical sensor, as long as the reaction zone is plated with a reaction medium, so that the light intensity changes due to the interaction between the test object and the reaction medium, the detection purpose can be achieved. The fiber grating sensor is mainly equipped with fast response, small size and weight
499565 五、發明說明(3) 輕、耐高溫高壓和不 於埋入結構物之腐蝕 用布拉格光栅做成感 成感應機制,而本發 光強度比值的變化量 光強度干擾,大大地 本發明是以光纖 光纖光柵所設計的光 光纖光柵之間。該兩 考訊號’另一個的反 柵的反射 光纖 十多年, 速,但對 法不但耗 上,可在 質;不但 也較傳統 及並聯數 件内部的 免因拆開 需的時間 用於建築 控鋼骨或 光強度之比 感測技術在 主要量測的 於腐蝕量的 時、複雜, 感測區鍵上 可以得到較 方式來得簡 個感測器達 腐姓情況, 機件所造成 及金錢。另 結構中的鋼 鋼筋的腐I虫 文電磁場干擾等特性,因此相當通合 或化學感測。雖過去已經有許多人採 測器,然都是以光柵波長的偏移量當 明係利用一對光纖光柵感測器的反射 作為感應機制,此新穎設計由於不受 提升強度型光纖感測器的應用價值。 漸瞬波場為基礎,並搭配一對布拉袼 纖感測器,其中將感測區放置在兩個 個光纖光栅中的一個的反射光作為參 射光作為感測訊號,利用兩個光纖光 值’以達到光強度擾動補償的效果。 發展量測物體物理量變化已經發 ?理量包括應力、溫度、壓力和流一 1測則較為不足;傳統的腐餘量測方 而且也比較不準確。在本發明的應用 一層金屬膜以做為腐蝕感測的感應介 為準確的腐蝕預測,而且在使用方面 旦最重要的一點是它可以串聯 夕:里測功能,並可即時檢測出機 而不必將機件拆下檢測,不但可以避 =可,期的損壞,也可以省下拆裝所 g二f人型光纖腐#感測器更可以使 預力混凝土中的麵筋,隨時監 狀况,以便及時作補強,避免因腐蝕499565 V. Description of the invention (3) Light, high temperature, high pressure and corrosion resistance of embedded structures. The Bragg grating is used to make the induction mechanism, and the change in the luminous intensity ratio changes the light intensity interference. Optical fiber gratings are designed between optical fiber gratings. The two test signals' the other anti-grating reflective fiber are more than ten years, fast, but the method is not only costly and can be used in quality; it is not only compared with the traditional and parallel internal several pieces of time required for disassembly for construction Controlled steel or light intensity ratio sensing technology is mainly used to measure the amount of corrosion when the measurement is complicated. The keys on the sensing area can be used to obtain a simple sensor to achieve the name of the rotten name. . In addition, the steel in the structure has the characteristics of electromagnetic field interference and other characteristics, so it is quite common or chemical sensing. Although many people have used sensors in the past, the offset of the grating wavelength is used as the sensing mechanism of the reflection of a pair of fiber grating sensors. This novel design is not affected by the enhanced fiber optic sensor. Application value. Based on the asymptotic wave field and paired with a pair of braided fiber sensors, the reflected light of one of the two fiber gratings placed in the sensing area is used as the reference light as the sensing signal, and two fiber lights are used Value 'to achieve the effect of light intensity disturbance compensation. The development of measuring physical changes in measuring objects has been developed. The physical quantities including stress, temperature, pressure, and flow are not sufficient; the traditional method of measuring residual quantities is also inaccurate. In the present invention, a layer of metal film is used as the sensing medium of the corrosion sensing for accurate corrosion prediction, and the most important point in use is that it can be connected in series and can be detected immediately without having to detect the machine. Detach and inspect the parts, not only can avoid the damage, but also save the disassembly and installation of the human-type optical fiber rot # sensor can make the gluten in the prestressed concrete, monitor the situation at any time, In order to make reinforcement in time to avoid corrosion
「々JO:) 五、發明說明(4) ' --- 破壞而造成傷害。除了腐蝕感測外,其他的生化感測亦可 利用本發明強度型光纖感測器的特殊設計達到在多點量測 及埋入主體而不受環境干擾的目的。 (一)強度型光纖光柵感測器之製作 本發明的強度型光纖感測器主要是以布拉格光纖光栅 f射特定波長的特性為基礎,包含一段具有蕊心與包圍該 蕊心的被覆層(Cladding)l〇5的光纖,該段光纖在其長軸 方向包含兩間隔開的布拉格光柵區1〇1、1〇2與介於該兩布 拉格光柵區之間的感測區1 q 3,如圖一所示,其中: 該兩布拉格光柵區101、102分別在其蕊心處被形成有 兩個不同反射波長的布拉格光柵;及 该感測區1 〇 3具有一外圍被覆層被移除一部分的縮小 被覆層及附著於該縮小被覆層外表面的反應介質層。 另外為了避免布拉格光柵區1 〇丨、1 〇 2及感測區丨〇 3直 接受到外在擾動影響,在其等外部裝上一多孔隙套筒 1 0 4 ’這多孔隙套筒可讓待測對象滲入,同時亦可防止側 面外力對光纖光柵產生雙折射(Birefringence)變化, 進而影響訊號處理。 本發明光纖光柵感測器的製作係首先以準分子雷射與 相位光罩在載氫(hydrogen loading)含鍺光纖上製作布拉 格光纖光柵(f iber Bragg grati ng,FBG)。利用不同週期 的相位光罩可以製作出不同中心波長的一對光纖光柵。使 用缓衝氧化物蝕刻(Buffered Oxide Etch (B0E))將兩個 光纖光栅之間的光纖被覆層除去,大約留下5 # m厚的被覆"々JO :) V. Description of the invention (4) '--- Damage caused by damage. In addition to corrosion sensing, other biochemical sensing can also use the special design of the strength type optical fiber sensor of the present invention to achieve multiple points The purpose of measuring and embedding the main body without being disturbed by the environment. (1) Fabrication of the intensity type fiber grating sensor The intensity type fiber sensor of the present invention is mainly based on the characteristics of a fiber Bragg grating f emitting a specific wavelength, The fiber comprises a core having a core and a cladding 105 surrounding the core. The section of the fiber includes two spaced apart Bragg grating regions 101, 102 in a long axis direction, and a space between the two. The sensing region 1 q 3 between the Bragg grating regions is shown in FIG. 1, wherein: the two Bragg grating regions 101 and 102 are respectively formed with two Bragg gratings with different reflection wavelengths at their cores; and the sensing region The measurement area 1 〇3 has a reduced coating layer with a part of the peripheral coating layer removed and a reaction medium layer attached to the outer surface of the reduced coating layer. In addition, in order to avoid the Bragg grating areas 1 〇, 1 〇2, and the sensing area 丨〇3 Directly received Under the influence of disturbance, a multi-porous sleeve 1 0 4 'is installed on the outside to allow the object to be infiltrated, and at the same time, it can prevent the external external force from causing birefringence changes to the fiber grating, which in turn affects Signal processing. The production system of the fiber Bragg grating sensor of the present invention first uses an excimer laser and a phase mask to produce a Bragg fiber grating (FBG) on a hydrogen-loaded germanium-containing fiber. Periodic phase masks can be used to make a pair of fiber gratings with different center wavelengths. Buffered Oxide Etch (B0E) is used to remove the fiber coating between the two fiber gratings, leaving about 5 # m Thick cover
第8頁 499565 五、發明說明(5) 層,再將蝕刻後之光纖以鍍膜或溶劑-凝膠(s〇1—Gel)的方 法附著上一層配合待測對象的反應介質層,即可完成強度 型光纖光栅感測器的製作。本發明可以作出具有串聯或並 聯的新型光纖光柵強度型感測器,可大大地改善一般強度 型感測器較無法串聯或並聯的缺點。適用於本發明的光接 收器可採用高靈敏(Avalanche Photodetector (APD))光 接收器以增加光強度變化的靈敏度。 (一)強度型光纖光柵感測器理論分析 就布拉袼光纖光柵的反射光強度而言,是非常容易受 到外界擾動、光源供應器和光譜儀的變動而產生光譜的光 強度變化,因而造成感測訊號的誤差和不準確。因應未來 光纖光柵感測器將會用於機械、橋樑與建築物的檢測,勢 必將感測器埋入結構體中;為了降低儀器和外界擾動所造 成量測的誤差,可將兩個反射光中心波長不同的布拉格光 纖光栅串接在一起,中間的區間隔著批覆有反應介質的感 測區1 0 3。圖一中前段的光纖光柵1 〇 1反射光強度不受反應 介質層變化的影響,後段光纖光柵1 02反射光強度受反應 介質層變化的影響。經過這種特別的設計,可將光纖光栅 1 01反射光作為光纖光栅1 〇 2反射光的補償;也就是說經過 光纖光栅反射光1 〇 1補償後,可消除光源供應器、光譜儀 和外界擾動所造成的影響。 為了進行多點量測功能,可將多値強度型光纖光柵感 測器串接起來。為了簡化說明,這裡以兩個光纖光柵感測 器1 0和11串接舉例說明,如圖二(a)所示。該感測器1〇,Page 8 499565 V. Description of the invention (5) layer, and then attach the etched optical fiber by coating or solvent-gel (s〇1-Gel) method to a layer of reaction medium that matches the object to be measured, and it can be completed. Fabrication of Intensity Fiber Grating Sensors. The invention can make a new type fiber grating intensity type sensor with series or parallel connection, which can greatly improve the disadvantage that general intensity type sensors cannot be connected in series or in parallel. The optical receiver suitable for the present invention can use a high-sensitivity (Avalanche Photodetector (APD)) optical receiver to increase the sensitivity of light intensity changes. (1) Theoretical analysis of the intensity type fiber grating sensor. As far as the reflected light intensity of the Bradford fiber grating is concerned, it is very susceptible to external disturbances, changes in the light source supplier and the spectrometer, resulting in changes in the light intensity of the spectrum. Errors and inaccuracies in the measured signals. As the future fiber grating sensor will be used for the detection of machinery, bridges and buildings, the sensor will be buried in the structure. In order to reduce the measurement error caused by the instrument and external disturbances, two reflected lights can be used. Bragg fiber gratings with different center wavelengths are connected in series, and the middle area is separated by a sensing area covered with a reaction medium 103. In Fig. 1, the intensity of the reflected light of the optical fiber grating 101 at the front stage is not affected by the change of the reaction medium layer, and the intensity of the reflected light of the fiber optic grating 100 at the rear stage is affected by the change of the reaction medium layer. After this special design, the fiber grating 1 01 reflected light can be used as compensation for fiber grating 1 〇2 reflected light; that is, after the fiber grating reflected light 1 〇1 compensation, the light source supplier, spectrometer and external disturbance can be eliminated. The impact. For multi-point measurement, multiple chirped fiber grating sensors can be connected in series. In order to simplify the description, two fiber grating sensors 10 and 11 are connected in series as an example, as shown in Figure 2 (a). The sensor 10,
第9頁 499565 五、發明說明(6) 是採用相位光罩(QPS Tech., Λριη = 1〇6〇,Grating Size = 10mm x 5mm, Zero order = 0.71%, +1 order = 39· 63%,-1 order = 38· 26%),經過準分子雷射加工之 後’製作出兩個相同布拉格光纖光柵,其中一個光纖光柵 施予一個預應力’使其中心波長產生飄移,因而製作出兩 個不同中心波長的光柵光纖1 〇 1、丨〇 2。該感測器丨丨則是採 用相位光罩(QPS Tech·, Apm = 1 070,Grating Size = 10mm x .5mm, Zero order = 0.51%, +1 order = 39· 48%, -1 order = 38· 88%),經過和該感測器j 〇相同的步 式(2)表示 驟所製作而成的(包含光柵光纖1 11、1丨2及感測區丨丨3 )。 如圖二(b)感測器光譜圖所示,其產生的反射光光譜表現 在光譜分析儀分別可用式(i ) 第一對可表示為: B1 λ Β1Page 9 499565 V. Description of the invention (6) is a phase mask (QPS Tech., Λριη = 106), Grating Size = 10mm x 5mm, Zero order = 0.71%, +1 order = 39 · 63%, -1 order = 38 · 26%), after excimer laser processing, 'made two identical fiber Bragg gratings, one of which was prestressed' to shift the center wavelength, thus producing two different Grating fiber 101 with a center wavelength. The sensor uses a phase mask (QPS Tech ·, Apm = 1 070, Grating Size = 10mm x .5mm, Zero order = 0.51%, +1 order = 39 · 48%, -1 order = 38 · 88%), made by the same step (2) as the sensor j 〇 (including the grating fiber 1 1 1, 1 丨 2 and the sensing area 丨 丨 3). As shown in the spectrum of the sensor in Figure 2 (b), the reflected light spectrum produced by the sensor can be expressed in the spectrum analyzer using formula (i). The first pair can be expressed as: B1 λ Β1
RbI (入 Β1 ) · SRbI (into Β1) S
Ai (1)Ai (1)
第二對可表示為:?B2(ti,AB2)=RB2( λΒ2) · S · vs · A〗 Pm2( tl,t2,λΜ2) = ΚΜ2 V 入 M2 ) · AM2 ( t2 ) A2mi (S · Vc )· V • A,2 · A2, (2)The second pair can be expressed as: B2 (ti, AB2) = RB2 (λB2) · S · vs · A〗 Pm2 (tl, t2, λM2) = KM2 V into M2) · AM2 (t2) A2mi (S · Vc ) · V • A, 2 · A2, (2)
其中PBi和PMi分別表示未受反應介質層影響的布拉格光纖 光撕和受反應介質層影響的光纖光柵反射光譜;和入1 表示兩個不同的布拉格波長;和Κ )分Where PBi and PMi represent Bragg fibers that are not affected by the reaction medium layer, respectively, and fiber grating reflection spectra that are not affected by the reaction medium layer; and 1 represents two different Bragg wavelengths; and κ)
第10頁 499565 五、發明說明(7) 別表不兩個布拉袼光纖光柵的反射比;t表 應介質層的厚度;i — 1 ’、感測區域反 柵感測器;另外,在#續八挤〆,ς矣-上运度i先纖光 银.v表干先5晋刀析上S表不光源所得的光 =a s 源密度的變動係數;、(、)表示含有反應介 吳層的^測器衰減係數;\分別表示在通路上外力擾動所 造成的哀減係數。 根據式(1)和式(2),可以得到兩個感測器感測信號 參考信號的比值。Page 10 499565 V. Description of the invention (7) Do not indicate the reflectance of two Bragg fiber gratings; t is the thickness of the dielectric layer; i — 1 ', the sensing area anti-grid sensor; In addition, the # Continuing eight squeezes, 矣 矣-the first degree i first fiber silver. V surface dry first 5 Jin knife analysis of the light obtained by the S surface light source = as the coefficient of variation of the source density; Detector attenuation coefficient of the layer; \ represents the decrement coefficient caused by the external force disturbance on the path. According to equations (1) and (2), the ratio of the reference signals of the two sensors can be obtained.
Rl ( tj )=--— ( ti , λΜ1 ) RmI (入 Ml ) · AM1 ( )Rl (tj) = ---- (ti, λΜ1) RmI (into Ml) AM1 ()
Pbi( λΒ1)Pbi (λΒ1)
RbI (久 B1RbI (long B1
Pm2 ( t , t2,λ M2 ) Rm2 (入 M2 ) · Am2 ( t 2 ) ( )---—------------- Ρβ2( ^B2) Rb2(入 B2) (3) 從式(3)可以很容易地發現這兩個比值,已經消除光 源和外力擾動的衰減係數。也就是說,這兩個比值的量並 不受光源和外力擾動的影響。所以在式(3 )中和量測參數 有關的只剩反應介質層的感測衰減係數。換句話說,不受 反應介質層影響的布拉格光纖光柵1 〇 1、Π 1和受反應介質 層影響的布拉格光纖光柵1 〇 2、1 1 2產生的反射光之比值, 將可建立起待測物質狀態和反應介質層的關係。 圖三顯示一用於說明本發明可運用於串聯感測,且不 499565 五、發明說明(8) 受外界擾動影響的基本架構圖。該架構由白光光源201和 光纖20 2〜205,一個2x2光纖耦合器2 06,5金度型光纖光柵 感測器1 0和1 1以及一台光譜分析儀3 0所組成。光譜分析儀 在此只是用於證明本設計的可行性,但若要避免訊號失真 的問題,可利用調變頻譜濾波器(如Optical Fiber Tunable Fabry-Perot Filters)取代光譜分析儀以提高訊 號擷取速度。在光纖202〜205處施予四個不同的外力,量 測外力對感測訊號的的影響。將四個位置的光譜訊號,製 作成圖四(a)〜(d)。圖四(d)是光纖2 0 5位置光纖受外力擾 動之光譜圖,因在光纖2 05產生外力擾動,所以僅僅對於 感測器11產生干擾,造成感測器11光譜產生衰減;感測器 11内的不受反應介質屬影響的布拉格光纖光柵1 11其反射 光強度從最高1· 825 nw至1· 049 nw,感測器11内的受反應 介質屬影響的布拉格光纖光柵112其反射光強度從最高 1· 378 nw至0· 80 3 nw,但兩反射光強度的比值的變動範圍 卻只從1 · 3 2 4至1 · 2 9 9,表示雖然反射光強度會受到外力擾 動的影響,但對於反射光強度的比值影響很小,同樣地在 光纖20 2〜204產生外力擾動,因外力擾動將對感測器1〇和 感測^§ 11同時造成擾動’如圖四(a )〜(c )所示。所以感測 器1 0和11内的不受反應介質層影響的布拉格光纖光柵 101、111和受反應介質層的布拉格光纖光柵102、Π2都會 產生衰減,但其比值變化相當的小,其誤差在2 %左右。將 四個位置2 0 2〜2 0 5所產生布拉格光纖光栅反射光比值製作 成圖四(e),從圖四(e)可以發現四個位置2 〇2〜2〇5的反射Pm2 (t, t2, λ M2) Rm2 (into M2) · Am2 (t 2) () ---------------- Pβ2 (^ B2) Rb2 (into B2) ( 3) From equation (3), it can be easily found that these two ratios have eliminated the attenuation coefficient of the light source and external force disturbance. In other words, the magnitude of these two ratios is not affected by the light source and external force. Therefore, in equation (3), the sensing attenuation coefficient of only the remaining reaction medium layer related to the measurement parameter. In other words, the ratio of the reflected light generated by the Bragg fiber grating 1 01, Π 1 not affected by the reaction medium layer and the Bragg fiber grating 1 0 2, 1 1 2 affected by the reaction medium layer, can establish the measurement The relationship between the state of matter and the reaction medium layer. Figure 3 shows a basic architecture diagram illustrating that the present invention can be applied to tandem sensing without 499565. 5. Description of the invention (8) Affected by external disturbances. The architecture is composed of a white light source 201 and optical fibers 20 2 to 205, a 2x2 fiber coupler 2 06, 5 gold-degree fiber grating sensors 10 and 11 and a spectrum analyzer 30. The spectrum analyzer is only used to prove the feasibility of this design, but to avoid the problem of signal distortion, you can use a modulation spectrum filter (such as Optical Fiber Tunable Fabry-Perot Filters) instead of the spectrum analyzer to improve signal acquisition. speed. Four different external forces are applied to the optical fibers 202 to 205 to measure the effect of the external force on the sensing signal. The spectral signals at the four positions are made into Figures 4 (a) ~ (d). Figure 4 (d) is the optical spectrum of the optical fiber at the position of the optical fiber at position 05. Because the external force is generated at the optical fiber at 05, it only interferes with the sensor 11 and causes the spectrum of the sensor 11 to be attenuated. The Bragg fiber grating 1 in 11 which is not affected by the reaction medium belongs to 11. The reflected light intensity is from 1.825 nw to 1.049 nw at the highest. The reflection of the Bragg fiber grating 112 in the sensor 11 which is affected by the reaction medium belongs to 112. The intensity ranges from the highest 1.378 nw to 0 · 80 3 nw, but the range of the ratio of the two reflected light intensities ranges from only 1 · 3 2 4 to 1 · 2 9 9, indicating that although the reflected light intensity will be affected by external force disturbances However, it has little effect on the ratio of the reflected light intensity. Similarly, an external force disturbance is generated in the optical fibers 20 2 ~ 204. The external force disturbance will cause disturbance to the sensor 10 and the sensing ^ § 11 at the same time, as shown in Figure 4 (a). ~ (C). Therefore, the Bragg fiber gratings 101 and 111 that are not affected by the reaction medium layer and the Bragg fiber gratings 102 and Π2 that are affected by the reaction medium layer in the sensors 10 and 11 will have attenuation, but the ratio changes are relatively small, and the error is About 2%. The reflected light ratio of the Bragg fiber grating generated at the four positions 2 0 2 to 2 0 5 is made into Fig. 4 (e). From Fig. 4 (e), the reflections at the 4 positions 2 0 2 to 2 05 can be found.
第12頁 499565 五、發明說明(9) 光強度比值都維持在一定值,感測器1 〇的反射光強度比在 1 · 0 6左右,而感測器11則維持在1 · 3 0左右,變動相當的 小。假若不經過補償的設計’在相同的外力干擾將會造成 很大變動,以光纖205位置外力擾動為例,受反應介質層 影響的布拉格光纖光柵1 12反射光能量從最高〖· 3^8 nw至 〇· 803 nw,其反射光強度的變動就高達4〇%,而其反射光 強度比值只有2%左右的變動’因此本強度光纖光柵感測器 的補償設計的方式將外力擾動所造成的干擾降到最低,而 達到本發明架構的目的。在未量測時,感測器丨〇及丨丨的每 對光纖光栅的兩訊號比值已先量化,做為每對感測區的量 測基準。當量測因子開始影響時,其一對光纖光柵的兩訊 號比值會隨著量測因子的變化而變化,而檢測出受感測的 情況,因此’可判斷量測因子所造成的影響。而每對光纖 光橋感測£疋以各反射的光拇頻譜做為區隔,以防各對光 纖光柵感測之間的串音問題。 圖五顯示溫度效應對本發明感測器之影響。將直徑 1 9 /z m的钱刻光纖經無電鍍銅處理後,使反應介質層厚度 增為直徑2 2 // m的感測區域1 0 3,紀錄溫度對反射光強度比 值的影響,從圖中可以發現,當溫度由2 5。(:改變至9 0 °C 時’反射光強度比值改變量為4%左右。其可能原因是蝕刻 光纖直徑相當的細微,在無電鍍銅過程中對蝕刻光纖產生 微彎曲(micro_bend)的影響,而溫度上升產生對蝕刻光纖 產生微拉伸(micro-tension),因而使反射光強度比值產 生4%的上升,可是因感測區金屬層造成反射光強度比值變Page 12 499565 V. Description of the invention (9) The light intensity ratios are all maintained at a certain value, the reflected light intensity ratio of the sensor 10 is about 1 · 0 6 and the sensor 11 is maintained at about 1 · 30 The change is quite small. If the design is not compensated, it will cause great changes under the same external force interference. Take the external force disturbance at the position of fiber 205 as an example. The reflected fiber energy of the Bragg fiber grating 1 12 affected by the reaction medium layer is from the highest 〖· 3 ^ 8 nw Up to 0 · 803 nw, the variation of the reflected light intensity is as high as 40%, and the ratio of the reflected light intensity is only about 2%. Therefore, the compensation design of the intensity fiber grating sensor is caused by external force disturbance. Interference is minimized, and the purpose of the present invention is achieved. When not measured, the ratio of the two signals of each pair of fiber gratings of the sensors 丨 〇 and 丨 丨 has been quantified first as the measurement reference for each pair of sensing areas. When the measurement factor starts to affect, the ratio of the two signals of a pair of fiber gratings will change with the change of the measurement factor, and the situation is detected. Therefore, the effect of the measurement factor can be judged. For each pair of optical fiber bridge sensing, the frequency spectrum of each reflected light is used as a separation to prevent crosstalk between the sensing of each pair of optical fiber gratings. Figure 5 shows the effect of temperature effects on the sensor of the present invention. After the money-cut optical fiber with a diameter of 19 / zm was electroless copper treated, the thickness of the reaction medium layer was increased to a sensing area with a diameter of 2 2 // m 1 0 3, and the effect of temperature on the ratio of reflected light intensity was recorded. It can be found when the temperature is from 2 to 5. (: The change in 'reflected light intensity ratio when changing to 90 ° C is about 4%. The possible reason is that the diameter of the etched fiber is quite small, which has a microbend effect on the etched fiber during the electroless copper plating process. The temperature rise causes micro-tension to the etched optical fiber, so that the reflected light intensity ratio increases by 4%, but the reflected light intensity ratio changes due to the metal layer in the sensing area.
第13頁 499565 五、發明說明(ίο) 化可以達到5 0 %以上,因此溫度效應對於本強度型光纖光 柵感測器所造成的干擾相當小。從實驗中證明反射光強度 並不受溫度的影響。另外,溫度和軸向應力只會造成光纖 ♦ 光柵的中心波長產生飄移,因本感測器是採用反射光能量 比作為量測機制,因此溫度和軸向應力不會造成訊號處理 的影響。 圖六顯示說明本發明光纖感測器的布拉格光纖光柵 和反應介質的反射光強度比值變化。以金屬腐蝕感測器為 例,量測反射光強度變動的範圍。在光纖被覆層去除的程 序中,製作三根被覆層殘留量分別為直徑1 9、2 1和2 8 // m _ 的光纖,將蝕刻後的光纖以無電鍍的方式在反應介質層鑛 ^ 上銅膜,為了增加無電鍍的效果,首先將蝕刻後的光纖放 入由氣化亞錫(SnCl2 ·2Η20)與鹽酸(HC1)以 (1 g - 4 m 1 )/ 1 0 0 m 1比例配製的敏化液浸泡2 0分鐘,再放入由 , 二氣化鈀(PdCl2)和鹽酸以(0· 025g-0· 25ml )/l〇〇ml比例配 , 製的活化液浸泡1 0分鐘,以提供無電鍍銅液在反應開始發 生的催化位置,接著以硫酸銅(CuS04 ·5Η20)以lg/l〇〇ml、 甲醛(HCH0)以 0.5ml/100ml、酒石酸鉀鈉(NaKC4H4 06 ·4Η20) 以2· 5g/100ml和氫氧化納(NaOH)以〇· 9g所配製無電鍍銅溶 液。將餘刻光纖浸泡無電鑛銅溶液,並同時利用光譜儀量禮_ 測每3 0秒反射光的變化,將反應介質的布拉格光纖光柵 1 0 2、1 1 2和不受反應介質的布拉格光纖光栅丨0 1、1丨丨根據 式(3)计异反射光強度比值,製作成圖六。其主要的趨勢 從這個實驗中可以發現,其反射光能量的比值變化範圍可Page 13 499565 V. Description of the invention (ίο) can reach more than 50%, so the temperature effect on the intensity optical fiber grating sensor will cause relatively small interference. It has been experimentally proven that the reflected light intensity is not affected by temperature. In addition, temperature and axial stress will only cause the center wavelength of the optical fiber to drift. Because this sensor uses the reflected light energy ratio as a measurement mechanism, temperature and axial stress will not affect the signal processing. Figure 6 shows the variation of the ratio of the reflected light intensity of the Bragg fiber grating and the reaction medium of the fiber sensor of the present invention. Take a metal corrosion sensor as an example to measure the range of the reflected light intensity variation. In the procedure of removing the optical fiber coating, three optical fibers with diameters of 19, 21, and 2 8 // m _ were produced, and the etched optical fibers were electrolessly plated on the reaction medium layer ore. Copper film, in order to increase the effect of electroless plating, first put the etched optical fiber into a ratio of (1 g-4 m 1) / 1 0 0 m 1 made of gasified stannous (SnCl2 · 2Η20) and hydrochloric acid (HC1) The sensitizing solution was immersed for 20 minutes, and then the activator solution soaked with palladium (PdCl2) and hydrochloric acid at a ratio of (0.025g-0.25ml) / 100ml was immersed for 10 minutes. To provide the electroless copper plating at the catalytic site where the reaction started, followed by copper sulfate (CuS04 · 5Η20) at lg / 100ml, formaldehyde (HCH0) at 0.5ml / 100ml, potassium sodium tartrate (NaKC4H4 06 · 4Η20) An electroless copper solution was prepared at 2.5 g / 100 ml and sodium hydroxide (NaOH) at 0.9 g. The remaining fiber is immersed in an electroless copper solution, and the spectrometer is used to measure the change of the reflected light every 30 seconds. The Bragg fiber grating 1 0 2 and 1 1 2 as the reaction medium and the Bragg fiber grating not affected by the reaction medium are measured.丨 0 1,1 丨 丨 Calculate the ratio of the intensity of the hetero-reflected light according to formula (3) and make it into Figure 6. The main trend It can be found from this experiment that the range of the ratio of the reflected light energy can be changed.
第14頁 499565 五、發明說明(11) 以達到5 0〜7 0 %左 光柵1 0 2、1 1 2和 反射光強度比值 收到腐钱的訊息 減變化或呈現不 徑相當細微,在 銅膜鍍層變化所 本發明最重 響’如光源變動 的干擾因素,亦 或並聯的方式達 值,還祈鈞局早 右。換句話說,當反應介貝μ,,—.…一… 不受反應介質的布拉格光纖光柵1 0 1、111 達到5 0%以上的變化量時,將可以斷定接 。同時在圖六反射光強度比值開始呈現衰 規則變化,其主要原因可能是蝕刻光纖 無電鍍過程中產生微彎曲所造成, 造成的影響。 儿非因 要的是可以完全排除外在環 、傳出/傳入光纖的彎、曲斤欠化的影 可設計成埋入型光纖€測·哭寺對感測訊號 到多點的量測功能;因:亚運用串聯 日鑒核並准予專利為队11 ’極具商業價 499565Page 14 499565 V. Description of the invention (11) In order to reach 50 to 70% of the left grating 1 0 2, 1 1 2 and the ratio of the reflected light intensity, the value of the received corrupted money is reduced or changed, or it does not appear quite small. The change of the film coating layer is the strongest of the present invention, such as the interference factors of light source changes, or the value achieved in a parallel manner. In other words, when the reaction medium μ, ........ a Bragg fiber grating 1 0 1, 111 not affected by the reaction medium reaches a change of more than 50%, it can be concluded that. At the same time, the reflected light intensity ratio in Figure 6 begins to show a decaying change. The main reason may be the effect of microbending caused by the electroless plating process of the etched optical fiber. The main reason is that the external loop, the bend of the outgoing / incoming optical fiber, and the underweight effect can be designed as an embedded optical fiber. The measurement of the crying temple to the multi-point measurement Function; because: Asia uses tandem diary to check and grant patent for team 11 'very commercial price 499565
圖一為本發明的強度型光纖感測器的示意圖,复 (以感測器1 0為例): /、τ 1 01不受反應介質層影響的光纖光柵; 1 0 2 ^:反應介質層影響的光纖光柵; 1 03光纖感測區; 1 0 4多孔隙套筒。 圖一(a)為本發明的串聯的強度型光纖感測器立 圖,其中: 思 1 0及11為兩串聯的感測器。 圖一(b)為圖二(a)的感測器1 〇及11反射光譜圖。 圖三為用於測試外界擾動對本發明的串聯強度型光纖 感測器的基本架構圖,其中: 光義感測為,2 〇 1白光光源;傳出/傳入2 〇 2〜2 〇 5 光纖;20 6 2x2光纖耦合器及30光譜分析儀。 圖四為光纖受側向應力時光纖感測器1 〇、1 1的光譜 (a) 20 2俸出/傳入光纖受外力擾動光譜圖 (b) 20 3傳出/傳入光纖受外力擾動光譜圖 (c) 20 4傳出/傳入光纖受外力擾動光譜圖FIG. 1 is a schematic diagram of an intensity type optical fiber sensor according to the present invention. (Take sensor 10 as an example): /, τ 1 01 fiber grating that is not affected by the reaction medium layer; 1 0 2 ^: reaction medium layer Affected fiber gratings; 103 fiber sensing area; 104 porous sleeve. Fig. 1 (a) is a perspective view of a series-strength fiber-optic sensor according to the present invention, where: 10 and 11 are two series-connected sensors. FIG. 1 (b) is a reflection spectrum diagram of the sensors 10 and 11 of FIG. 2 (a). FIG. 3 is a basic structural diagram of a series intensity optical fiber sensor for testing the external disturbance to the present invention, wherein: photo-sensing sensing is a 021 white light source; outgoing / incoming 2 0 ~ 2 0 5 optical fiber; 20 6 2x2 fiber coupler and 30 spectrum analyzer. Figure 4 shows the spectrum of the optical fiber sensors 10 and 11 when the optical fiber is subjected to lateral stress. (A) 20 2 The outgoing / incoming fiber is disturbed by external force. (B) 20 3 The outgoing / incoming fiber is disturbed by external force. Spectrum (c) 20 4 Spectrum of outgoing / incoming fiber disturbed by external force
(d) 205傳出/傳入光纖受外力擾動光譜圖, (e) 為(a)至(d)中光纖感測器1〇、u的反射光強度比值 圖五顯示溫度效應對本發明感測器之影響。 丄示本發明光纖感測器的反應介質i變化對反 光強度比值的影響。(d) Spectrum of 205 outgoing / incoming fiber disturbed by external force, (e) is the ratio of reflected light intensity of fiber sensor 10 and u in (a) to (d). Figure 5 shows the temperature effect on the sensing of the present invention. Effect of the device. The effect of the change in the reaction medium i of the optical fiber sensor of the present invention on the reflection intensity ratio is shown.
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