A7 B7_· · 五、發明説明（1 ) 發明領域 本發明係有關於一種光學波長選擇裝置，且特別有關於 一種裝置用以多工/解多工在光學網路中的光學傳輪波道， 例如一增加/衰落多工器。 發明背景 在此項技術中已知有很多在網路中增加現存光纖容量的 不同方法。一種方法是使用波長劃分多工（WDM)以改善使 用於光學網路中的光纖可用頻寬的範困。然而，此項技術 需要提供裝置，可以將加於光學網路中不同的所謂光學載 波波長的傳輸波道予以多工及解多工。 某一特別有關於所謂匯流排網路或環形網路的多工型態 是增加/衰落多工，也就是一種方法，其中安排在上述載波 波長上的一或多個所謂資訊波道是自一資訊流中減少或增 加。 發明簡述 已知一光學傳輸系统的容量可以多種不同方式增加，例 如’在波長多工中，傳輸波道是經多工及經解多工於不同 的載波波長上以獲得一資訊流。 經濟部中央橾準局貞工消费合作社印製 (锖先閏讀背面之注填寫本霣) 一已知技術所遭遇的問題的例子是和增加/衰落波道及傳 輪波道有關的高功率損耗。 另一問題是要維持一可接受的波道_音位準。 本發明輔次一光學裝置來著手解決這些問題，該裝置包 括至少一ΜΜΙ結構，至少一布拉格柵及至少二個所謂通路 導波管用以連接至外部光學裝置或光纖。 本纸張尺度適用中國國家揉準（CNS ) Α4规格（210X297公釐） A7 B7 五、發明説明（2) 上述MMI結構（多重模式干擾）有能力使該MMI結構的諸 輸入之一處的光強度分佈映射至該MMI結構的所有輸出 上。MMI結構因此可以用來分光。本發明的情形中，MMI 導波管的長度係選擇來獲得1 :1的映射，換言之，在最佳 的情況下，來自 提供於該MMI導波管上的第一通路導波 管的輸入光係聚焦於佈置於相對於該第一通路導波管之相 對側上的第二通路導波管》—MMI結構背後更基礎的理論 係描述於專利説明書DE 2506272及在L.B.中Soldano及E.C.M. Pennings 所寫的"Optical Mu.lti-Mode Interference Devices Based on Self-Imaging : Principles and Application"，光波技 術期刊1995年第13(4)卷第615-627頁。 布拉格柵是用來過濾光線。此濾波過程涉及允許特定波 長的光通過該柵而反射其他波長的光線。布拉格栅可説是 構成某些形式的波長選擇鏡。可以幾種不同方式獲得特定 波長的反射。然而，典型地有幾種方法藉著週期地改變導 波管中的所謂材料係數而使反射發生》 此進步的裝置.亦可包括一所謂的相位控制元件。該相位 控制元件影響導波管中所謂的光波長。可以藉著施加一外 部信號至導波管而產生。 經濟部中央搮準扃貝工消費合作社印装 (請先w讀背面之注填寫本i ) 獲得相位控制的方法是將該導波管遭受一可改變導波管 有效折射率的電場。 相位控制亦可藉著使導波管遭受熱改變而獲得。 永久改變導波管折射率的一種方法是將導波管曝露於紫 外光中。這通常被稱爲導波管是被紫外光窝入（UV- 本纸張尺度適用中國國家標準（CNS ) A4规格（2丨0X297公釐） A7 B7 五、發明説明（3)A7 B7_ · V. Description of the Invention (1) Field of the Invention The present invention relates to an optical wavelength selection device, and more particularly, to a device for multiplexing / demultiplexing an optical transmission channel in an optical network. An example is an increase / decrease multiplexer. BACKGROUND OF THE INVENTION There are many different methods known in the art for increasing the capacity of existing fibers in a network. One method is to use wavelength division multiplexing (WDM) to improve the range of available bandwidth for optical fibers used in optical networks. However, this technology needs to provide a device that can multiplex and demultiplex the transmission channels of different so-called optical carrier wavelengths added to the optical network. A particular type of multiplexing on the so-called bus network or ring network is increase / fading multiplexing, which is a method in which one or more of the so-called information channels arranged on the above-mentioned carrier wavelength are self-contained. Decrease or increase in information flow. SUMMARY OF THE INVENTION It is known that the capacity of an optical transmission system can be increased in a number of different ways. For example, 'in wavelength multiplexing, a transmission channel is multiplexed and demultiplexed at different carrier wavelengths to obtain an information stream. Printed by the Central Labor Department of the Ministry of Economic Affairs, Jeonggong Consumer Cooperative (read the note on the reverse side first and fill in this). An example of a problem encountered with known technologies is the high power associated with increasing / decreasing channels and transmission channels. loss. Another problem is to maintain an acceptable channel_tone level. The present invention assists in solving these problems with an optical device. The device includes at least one MMI structure, at least one Bragg grid, and at least two so-called channel waveguides for connecting to external optical devices or optical fibers. This paper size applies to China National Standards (CNS) A4 (210X297 mm) A7 B7 V. Description of the invention (2) The above MMI structure (multi-mode interference) has the ability to make light at one of the inputs of the MMI structure The intensity distribution is mapped to all outputs of the MMI structure. The MMI structure can therefore be used to split the light. In the case of the present invention, the length of the MMI waveguide is selected to obtain a 1: 1 mapping, in other words, in the best case, the input light from the first channel waveguide provided on the MMI waveguide "Focus on the second channel waveguide arranged on the opposite side of the first channel waveguide"-a more basic theory behind the MMI structure is described in the patent specification DE 2506272 and Soldano and ECM Pennings in LB "Optical Mu. Lti-Mode Interference Devices Based on Self-Imaging: Principles and Application", Lightwave Technology Journal 1995, Vol. 13 (4), pp. 615-627. The Bragg grid is used to filter light. This filtering process involves allowing light of a specific wavelength to pass through the grid while reflecting light of other wavelengths. The Bragg grating can be said to constitute some form of wavelength selective mirror. Reflections at specific wavelengths can be obtained in several different ways. However, there are typically several ways to make reflections occur by periodically changing the so-called material coefficients in a waveguide. This progressive device can also include a so-called phase control element. This phase control element affects the so-called light wavelength in the waveguide. It can be generated by applying an external signal to the waveguide. Printed by the Central Ministry of Economic Affairs, the Zhuhai Gonggong Consumer Cooperative (please read the note on the back and fill in this i). The method for obtaining phase control is to subject the waveguide to an electric field that can change the effective refractive index of the waveguide. Phase control can also be obtained by subjecting the waveguide to thermal changes. One way to permanently change the refractive index of a waveguide is to expose the waveguide to ultraviolet light. This is commonly referred to as a waveguide that is nested by ultraviolet light (UV- This paper size applies the Chinese National Standard (CNS) A4 specification (2 丨 0X297 mm) A7 B7 V. Description of the invention (3)
Written)。此技術最常用來獲得週期性的折射率變動，即 所謂的紫外光寫入。此技術亦可用作調整或校正之用β 上述過濾方法及在導波管中執行相位控制的方法只藉由 例子給予，且並不排除和本發明有關的未提及方法的應 用0 本發明包括一 ΜΜΙ結構，其中配置有一布拉格柵β該布 拉格栅最好配置在該ΜΜΙ結構的中心》通路導波管是提供 於該ΜΜΙ結構上。這些位在ΜΜΙ結構的通路導波管的位置 是決定光學裝置的功能》本發明一方面藉由多個不同的 ΜΜΙ結構實施例，另一方面藉由多個通路導波管結合布拉 格柵而解決上述問題。 \y/ 本發明的目的因此係提供一光學裝置，具有較小的功率 損耗，較少波道串音及和已知技術相較在不同的傳輸波道 間具有較小的功率變動β 本發明提供的一項優點在於該裝置較已知裝置更簡潔 ct)。 另一優點在於該進步的光學裝置可以相當便宜地製造。 本發明現在將參考較佳實施例及伴随的圖式加以詳述。 圖式簡述 經濟部中央梂準局貝工消费合作社印装 (請先S讀背面之注$^填寫本霣) 圖1例舉一根據本發明之光學波長選擇裝置的實施例β 圖2例舉一進步的光學波長選擇裝置的另一實施例。 囷3例舉一進步的光學波長選擇裝置的進一步實施例β 圖4例舉一進步的光學波長選擇裝置的更進一步實施例β 困5例舉一進步的光學波長選擇裝置的另一實施例。 本纸張尺度適用中國國家標芈（CNS >八4规格（2ΐ〇χ297公釐） 經濟部中央樣準局貝工消费合作社印製 修正 補充 A7 B7 第86110092號專利申請案 中文説明書修正頁(87年9月） 五、發明説明（ 圖6例舉一進步的光學波長選擇裝置的更另一實施例。 元件代表符號 1 通路導波管 2 通路導波管 3 通路導波管 4 通路導波管 1 0通路導波管1之中心線 20通路導波管2之中心線 30通路導波管3之中心線 40通路導波管4之中心線 50布拉格柵 6 0増加之折射率區域 較佳實施例的簡述 圖1例舉一進步的光學波長選擇裝置的實施例，該光學波 長選擇裝置包括一布拉格柵5〇及一 MMI導波管。該布拉格 柵5 0可配置在該μ Μ I導波管中，使得其中心線與該Μ ΜI 導波管的中心線一致。由圖1很明確地，該布拉格栅亦可配 置在距離該ΜΜΙ導波管短側L/2 + Lphc的距離處，其中 Lphc指出距離該ΜΜΙ導波管中心的位移。Lphc可正可 負。該布拉格柵偏移於該Μ ΜI導波管的中心，以便補償該 與模式有關的相位偏移，該相位偏移可能威脅到裝置的功 能。該布拉格柵具有一給定寬度標號爲LBg 3該ΜΜΙ導波 管具有一給定長度在圖1中標號爲L。 所謂通路導波管1，2，3，4可提供於該Μ ΜI導波管的短 本紙張尺度逍用中國國家揉準（CNS } A4规格（210X297公釐） • * Ψ ---:------------IT---------- {請先《讀背面之注意事項再填寫本頁) 經濟部中央揉準局負工消费合作社印製 第86110092號專利申請案 ' 中文説明書修正頁(87年9月） ^ ·五、發明説明（) 側上。圖1的實施例包括四個通路導波管，也就是每個短側 上二個通路導波管《通路導波管的數目隨實施例而改變， 端視該光學波長選擇裝置的用而定。該等通路導波管的中 心線10，20，30及40已顯示於圖中β 導波管的長 側到該通路導波管1的中心線！ 〇的距離在圖i中標爲a ^由 該ΜMI導波管的相同長侧到該通路導波管2的中心線2〇的 距離在圖1中標爲b。類似地，由該μ ΜI導波管的長側到其 餘通路導波管3及4的距離分別標爲c及d。距離a* cm可相 等且距離b和d亦可相等。距離a，b，c及d將視MMI導波 管的有效寬度We，影像的數目及有關河^1導波管的型態 而定。不同Μ ΜI導波管背後隱藏的深厚理論是描述於波爾 7a 本紙張尺度適用中國國家搮準（CNS ) A4規格（2丨OX297公釐） • * > ---^-------------1T------.---- (請先閱讀背面之注$項再填寫本頁) 經濟部中夬揉準局工消费合作社印製 A7 B7 五、發明説明（5 ) A貝思（Pierre A. Besse)等人的文章中，標題是多重模式 干擾耦合僉的光學頻寬及製造誤差’光波技術期刊1994年 第 12(4)卷第 1004-1 009 頁。 該MMI導波管的有效寬度We端視波長λ，在該MMI導波 管中的折射率躍階，該ΜΜΙ導波管的實體宽度及光線的偏 極化而定。 該ΜΜΙ導波管的長度端視該導波管的有效寬度We及要求 功率而定。 在圖1的實施例中，該等通路導波管和該MMI導波管的 ,接頭處較其自由端爲寬。此結構正常被稱爲逐漸變細結 -1 .- ' 構。此結構的效果是和直線通路導波管相較，可以改變光 場。這樣導致與該等通路導波管的誤差修正有關的較大誤 差。此外，此效果於較低階模式中存在於較大的範困，這 樣是有益的，因爲布拉格柵會針對反射波道給予一和模式 有關的移相。 該圖解的光學波長選擇裝置亦可包括一相位控制元件》 此相位控制元件可以任一不同的方式配置β多種可想得到 的配置相位控制元件的方式已於本發明的標題簡述中给予 且爲熟習此項技藝之人士所已知，因此將不會在本發明中 詳述。 ®2例舉進步的光學波長選擇装置的另一實施例。如同早 先敘述的實施例，圖2的實施例包括一布拉格柵50及一 ΜΜΙ導波管。該布拉格柵的寬度被標爲LBg。ΜΜΙ導波管 的長度標爲L，就如同前述的實施例一般》此實施例和該 ** 8 - 本紙張尺度速用中國國家揉準（CNS > A4规格（210X297公釐） II丨丨Ί—iII (請先蹋讀背面之注$访填寫本寊) 订 姝 Α7 Β7 經濟部中央標準局負工消费合作社印製 五、發明説明（6 ) 第一個實施例的差別在MMMI導波管的型式。類似於導波 管1，2, 3及4,此導波管是逐漸變細β導波管的長 側於ΜΜΙ導波管的徑向方向在環繞布拉格栅的兩側有一段 短距離是互相平行的，且在ΜΜΙ導波管的徑向方向上和鏡 像中心線垂直。·直接相鄰於布拉格柵的ΜΜΙ導波管的寬度 標爲W2。ΜΜΙ導波管的短侧寬度標爲wi，其中 W1<W2 ο 由圈2很蘋然的是，ΜΜΙ導波管可包括一具有長度L3的 最後部。在另一實施例中，長度L3可等於〇。在MMI導波 管的寬度W1及W2間的結構是逐漸變細。該逐漸變細結構 可以是線性’抛物線或其他形狀。在此圖解例中，該逐漸 變細結構的目的在 通路導波管1，· 2，3及4是配置在ΜΜΙ導波管的短辦上。 在圖2的實施例中，兩個這樣的通路導波管是配置在每個短 側上。各別通路導波管1，2，3及4的中心線1 〇，2 0 , 3 0 及40已顯示於圖中，如同前個實施例所例舉的。從短側的 一端到通路導波管1的中心線10的距離標爲a ^從該短側相 同一端到通路導波管2的中心線20的距離標爲b。類似地， 其餘導波管距另一短側的距離標爲c及d。距離a和c可相 等，且距離b和d亦可相等。參考前個實施例所提的，布拉 格栅可配置在M^ll導波管的._中心或稍微偏離該中心。布拉 格栅偏離導波管中心的眞正理由相同於參考前個實施例所 提的’換言之，爲了補償任何與模式有關的相位偏移。 19 - 本纸張尺度適用中國國家樑準（CNS )八4规格（21〇X297公釐） —I.---：---ί t婧先；8讀背面之注$\ ..球寫本賓) 訂 線 脅 經濟部中央揉準局貝工消費合作社印裝 Α7 Β7 五、發明説明（7 )· 圈3例舉進步的光學波長選擇裝置的另一實施例。此實施 例和圈2實施例間的唯一差異在於所謂的光學路徑長和多個 通路導波管有關》在圈3的實施例中，藉著將導波管配置在 MMI導波管向外突出部上，通路導波管2及3的光學路徑長 已獲得延伸這些向外突出部的寬度在圖3各別標爲e及f»距 離e及f可相等或不相等，端視要求的結果而定。當然，有 可能將任一通路導波管，一或多個該導波管配置於該MMI 導波管上之某種型式之裝置上，該MMI導波管會改變光學 路徑長。改變给定通道導波管的路徑長的目的是補償與模 式有關的移相。如果我們假設MMI導波管的長度L對應到 一所謂的交叉模式（cross-mode)，則藉著增加MMI導波 管的長度至2L，有可能獲得一所謂的條紋模式（bar -mode) 如該各詞所能推知的，交叉模式意指一種模式，其中至少 一來自MMI導波管一側的波長波道是透過該MMI導波管傳 輸，以便能聚集於該MMI導波管另一側上的通路導波管 上’該通路導波管係和信號射出的通路導波管呈一橫向偏 移的關係。交叉模式的一個例子是當一波長波道傳輸自通 路導波管10且聚集於通路導波管40上》條紋模式意指一波 長波道傳輸自位在MMI導波管一側上的一通路導波管，且 聚焦於佈置於該Μ ΜI導波管另一側上的一相對應通路導波 管上β條紋模式的一個例子是常一波長波道傳輸自通道導 波管10且聚焦於通路導波管30上。 囷4例舉進步的光學波長選擇裝置的進一步實施例β在此 實施例中，兩個ΜΜΙ導波管係交互配置。該等導波管已藉 -10- 本纸張尺度適用中國國家揉準（CNS ) A4规格（210X297公釐） -----------^— (請先Κ讀背面之注fΪΚ格寫本I) ir 嫌 A7 A7 經濟部中央搮準局貝工消费合作社印装 m * ________B7___ 五、發明説明（8 ) 由一導波管或一光纖相接合《各別MMI導波管的結構基本 上類似於圖2所示的結構，除了在各端點中，其已接合在一 起。由圖4可看出這些端點只包括一通路導波管。再者，各 別短側的部分p，q並不垂直於該通路導波管的中心線β理 由是使ΜΜΙ導波管中不必要的光線在此結構的此部分被折 射’且自該處消失β兩個連續配置的ΜΜΙ導波管的串接 (cascade)具有降低串音（cross-talk)的效果。在此實施 例中包括一在本發明之簡述中提及的相位控制元件種類亦 是切實可行的。任何要求數目的通路導波管可配置在此兩 個MMI導波管上，雖然該等通路導波管最好是一側上兩個 且另一相對側上兩個。由圖中很顯然的是，布拉格栅可偏離 MMI導波管的中心或配置在該導波管的中心上。 圖5例舉進步的光學波長選擇裝置的另一實施例，其中兩 個MMI導波管可直接组合β 由圖5可以看到，此實施例的MMI導波管在一側上單獨 逐漸變細’而該通路導波管係配置在該側上β ΜΜΙ導波管 的各別長側在兩個布拉格栅之間互相平行。一個ΜΜΙ導波 管的中心線和其他ΜΜΙ導波管的中心線呈平行而側向偏移 的關係。爲了減少在ΜΜΙ導波管中不必要光線的反射，ρ 及q部分在各別的ΜΜΙ導波管中成一角度，該等部分粗略 來説是該中心線前述側向平行侔移的剩餘部分。 此實施例亦可包括本發明簡述中提及的該類相位控制元 件。任何要求數目的通路導波管可配置在各別MMI導波管 的自由端中，和此數目有關的實際限制是由該等MMI導波 -11- 本紙張尺度適用中國國家橾準（CNS ) A4規格（210X297公釐） I----Τ-Ι-ΓΙ 裝------訂------線 (请先Μ读背面之注fi»填寫本霣) A7 * " —_____—_B7_ —__ 五、發明説明（9 ) 管的尺寸所決定。 將該等通路導波管配置在上述向外突出部的另一選擇 是，該等MMI導波管的折射率可連接適當的通路導波管而 改變但卻獲得相同的效果，也就是説，改變導波管中 的光學路徑長目的在於補償和模式有關的相位偏移。此另 一選擇係例舉於圖6。在此實施例中，MMI導波管的折射 率已於矩形區域60增加，該區域直接相鄰於一對通路導波 管而該矩形的縱向中心線相合於各別通路導波管的中心 線。藉著經由例如紫外線寫入而轉變MMI導波管中的現有 材料，可以獲得折射卑的改變。該折射率改變的型式及尺 寸對於獲得此效果有決定性的影響。 此進步的裝置可適合由諸如石英（Si 〇2)，聚合物材料， 一些半導體系或氧化鈮鋰（lithiumniobate) (LiNb03)所製 造，雖然最好是用石英。 可以理解的是本發明並不限於上述及例舉的實施例，且 可在下列申請專利範園内作修改。 (请先Μ讀背面之注$項/填寫本寊) ----装------訂 線 經濟部中央橾準局貝工消費合作社印製 ___-12- 本紙張尺度適用中國國家標準（CNS ) A4规格（210X297公逢）Written). This technique is most commonly used to obtain periodic refractive index changes, so-called ultraviolet writing. This technique can also be used for adjustment or correction β The above-mentioned filtering method and the method of performing phase control in a waveguide are given by way of example only, and do not exclude the application of unmentioned methods related to the present invention. 0 The present invention It includes a MMI structure, which is provided with a Bragg grid β. The Bragg grid is preferably arranged in the center of the MMI structure. A channel waveguide is provided on the MMI structure. The position of these channel waveguides in the MMI structure determines the function of the optical device. The present invention is solved on the one hand by using multiple different MMI structure embodiments and on the other hand by combining multiple channel waveguides with Bragg grids. The above problem. \ y / The purpose of the present invention is therefore to provide an optical device with less power loss, less channel crosstalk and smaller power variations between different transmission channels compared to known technologies. β The present invention One advantage provided is that the device is more compact than known devices (ct). Another advantage is that this advanced optical device can be manufactured relatively inexpensively. The invention will now be described in detail with reference to a preferred embodiment and accompanying drawings. Schematic description of the printing by the Central Laboratories of the Ministry of Economic Affairs, Shellfish Consumer Cooperatives (please read the note at the back of $ ^ to fill out this note) Figure 1 illustrates an embodiment of an optical wavelength selection device according to the present invention β Figure 2 For another example of an improved optical wavelength selection device.囷 3 exemplifies a further embodiment of an improved optical wavelength selection device β FIG. 4 exemplifies a further embodiment of an improved optical wavelength selection device β 5 exemplifies another embodiment of an improved optical wavelength selection device. This paper size applies to the Chinese national standard (CNS > 8-4 size (2 × 297 × 297 mm). Printed and supplemented by the Central Bureau of Standards, Ministry of Economic Affairs, Shellfish Consumer Cooperative, A7, B7, No. 86110092 Patent Application, Chinese Manual, Amendment Page (September 87) V. Description of the invention (Figure 6 illustrates yet another embodiment of a progressive optical wavelength selection device. Element representative symbols 1 channel waveguide 2 channel waveguide 3 channel waveguide 4 channel waveguide Wave tube 1 0 center line of waveguide 1 20 center line of waveguide 2 30 center line of waveguide 3 40 center line of waveguide 4 50 center line of waveguide 4 50 Bragg grating 6 0 Brief Description of the Preferred Embodiment FIG. 1 illustrates an embodiment of a progressive optical wavelength selection device. The optical wavelength selection device includes a Bragg grid 50 and an MMI waveguide. The Bragg grid 50 can be arranged in the μM In the I waveguide, its center line is consistent with the center line of the MIMO waveguide. As is clear from Fig. 1, the Bragg grating can also be arranged at a distance L / 2 + Lphc from the short side of the MIMO waveguide. Distance, where Lphc indicates the distance from the MMI guided wave Displacement of tube center. Lphc can be positive or negative. The Bragg grid is offset from the center of the MIMO waveguide in order to compensate for the mode-dependent phase offset that may threaten the function of the device. The Bragg The grid has a given width, labeled LBg 3, and the MMI waveguide has a given length, labeled L in Figure 1. The so-called channel waveguides 1, 2, 3, and 4 can be provided in the M MI waveguide. Short paper size standard for use in China (CNS) A4 size (210X297 mm) • * Ψ ---: ------------ IT ---------- {Please read "Notes on the back of the page before filling in this page." Patent Application No. 86110092 printed by the Central Labor Bureau of the Ministry of Economic Affairs, Consumer Cooperatives, printed 'Chinese Manual Correction Page (September 1987) () Side. The embodiment of FIG. 1 includes four channel waveguides, that is, two channel waveguides on each short side. The number of channel waveguides varies with the embodiment, depending on the optical wavelength selection. Depending on the device, the centerlines 10, 20, 30, and 40 of these waveguides are shown in the figure. The distance from the centerline of the tube 1! Is marked as a in Figure i. The distance from the same long side of the MMI waveguide to the centerline 20 of the channel waveguide 2 is marked as b in Figure 1. Similarly, The distances from the long side of the μMI waveguide to the remaining channel waveguides 3 and 4 are labeled c and d, respectively. The distance a * cm can be equal and the distances b and d can be equal. The distances a, b, c and d will depend on the effective width We of the MMI waveguide, the number of images, and the type of the river ^ 1 waveguide. The deep theory hidden behind the different MIMO waveguides is described in Bol 7a. This paper scale applies China National Standard (CNS) A4 specification (2 丨 OX297 mm) • * > --- ^ ------------- 1T ------.---- ( Please read the note on the back before filling in this page.) Printed by the Ministry of Economic Affairs, Prospective Bureau Industrial Cooperative Consumer Cooperative, printed A7 B7 V. Invention Description (5) Articles by Pierre A. Besse and others, title It is the optical bandwidth and manufacturing error of multi-mode interference coupling chirped light 'Journal of Wave Technology 1994 Vol. 12 (4) pp. 1004-1 009. The effective width We end of the MMI waveguide depends on the wavelength λ, the refractive index step in the MMI waveguide, the physical width of the MMI waveguide, and the polarization of the light. The length end of the MMI waveguide is determined by the effective width We of the waveguide and the required power. In the embodiment of FIG. 1, the joints of the channel waveguides and the MMI waveguides are wider than their free ends. This structure is normally referred to as the tapered structure -1 .- 'structure. The effect of this structure is that it can change the light field when compared to a linear waveguide. This leads to large errors related to the error correction of these channel waveguides. In addition, this effect exists in the larger range in lower-order modes, which is beneficial because the Bragg grid will give a mode-dependent phase shift for the reflected channel. The illustrated optical wavelength selection device may also include a phase control element. This phase control element may be arranged in any of different ways. Β. Various conceivable ways of configuring the phase control element have been given in the brief description of the present invention and are familiar with this. Those skilled in the art are known and therefore will not be described in detail in the present invention. ®2 exemplifies another embodiment of the advanced optical wavelength selection device. As with the previously described embodiment, the embodiment of Fig. 2 includes a Bragg grid 50 and a MMI waveguide. The width of the Bragg grid is labeled LBg. The length of the MMI waveguide is marked as L, just like the previous example. This example and the ** 8-This paper size is quickly used in China (CNS > A4 size (210X297 mm) II 丨 丨Ί—iII (please read the note on the reverse side first to fill in this book) 姝 A7 Β7 Printed by the Central Consumers Bureau of the Ministry of Economic Affairs and Consumer Cooperatives V. Description of the invention (6) The difference of the first embodiment is in the MMMI guided wave Type of tube. Similar to wave guides 1, 2, 3 and 4, this wave guide is tapered. The long side of the β wave guide is in the radial direction of the MMI wave guide with a section around the sides of the Bragg grating. The short distances are parallel to each other and perpendicular to the mirror center line in the radial direction of the MMI waveguide. The width of the MMI waveguide directly adjacent to the Bragg grating is labeled W2. The short side width of the MMI waveguide Marked as wi, where W1 < W2 ο by circle 2, it is natural that the MMI waveguide may include a last portion having a length L3. In another embodiment, the length L3 may be equal to 0. In the MMI waveguide The structure between the widths W1 and W2 is tapered. The tapered structure can be a linear 'parabola Or other shapes. In this illustrated example, the purpose of the tapered structure is that the channel waveguides 1, 2, 3, and 4 are arranged on the short tube of the MMI waveguide. In the embodiment of FIG. 2, Two such channel waveguides are arranged on each short side. The centerlines of the respective channel waveguides 1, 2, 3 and 4 1 0, 2 0, 3 0 and 40 are shown in the figure, as As exemplified in the previous embodiment, the distance from the short-side end to the center line 10 of the channel waveguide 1 is labeled a ^ The distance from the same end on the short side to the center line 20 of the channel waveguide 2 is labeled b. Similarly, the distances of the remaining waveguides from the other short side are labeled c and d. The distances a and c may be equal, and the distances b and d may be equal. Referring to the previous embodiment, the Bragg grating may be The ._ center of the M ^ ll waveguide is or slightly deviated from the center. The reason why the Bragg grid deviates from the center of the waveguide is the same as that mentioned in the previous embodiment, in other words, in order to compensate for any mode-related phase 19-This paper size is applicable to China National Liang Zhun (CNS) 8-4 specifications (21 × 297 mm) —I .---: --- ί t Jing ; 8 notes on the back of the reading $ \ .. ball writes this guest) The line is printed by the Central Government Bureau of the Ministry of Economic Affairs, printed by the Shellfish Consumer Cooperative, A7 Β7 5. Description of the invention (7) · Circle 3 examples of progressive optical wavelength selection devices Another embodiment. The only difference between this embodiment and the embodiment of circle 2 is that the so-called optical path length is related to multiple channel waveguides. In the embodiment of circle 3, the waveguide is arranged to protrude outward by arranging the waveguide in the MMI waveguide. The optical path lengths of the waveguides 2 and 3 have been extended, and the widths of these outwardly protruding parts have been respectively marked as e and f in Figure 3. The distances e and f can be equal or unequal. It depends. Of course, it is possible to arrange any channel waveguide, one or more of the waveguides on a certain type of device on the MMI waveguide, and the MMI waveguide will change the optical path length. The purpose of changing the path length of a given channel waveguide is to compensate for the mode-dependent phase shift. If we assume that the length L of the MMI waveguide corresponds to a so-called cross-mode, then by increasing the length of the MMI waveguide to 2L, it is possible to obtain a so-called bar-mode such as As can be inferred by the terms, the cross mode means a mode in which at least one wavelength channel from one side of the MMI waveguide is transmitted through the MMI waveguide so that it can be gathered on the other side of the MMI waveguide On the channel waveguide on the 'the channel waveguide system and the channel waveguide where the signal exits in a lateral offset relationship. An example of the cross mode is when a wavelength channel is transmitted from the channel waveguide 10 and concentrated on the channel waveguide 40. The stripe mode means that a wavelength channel is transmitted from a channel located on one side of the MMI waveguide. An example of a beta stripe pattern focused on a corresponding channel waveguide disposed on the other side of the MIMO waveguide is a waveguide, and a constant-wavelength channel is transmitted from the channel waveguide 10 and focused on On the waveguide 30. (4) A further embodiment of the advanced optical wavelength selection device is exemplified. [Beta] In this embodiment, two MMI waveguide systems are alternately configured. These waveguides have borrowed -10- This paper size is applicable to China National Standard (CNS) A4 (210X297 mm) ----------- ^ — (Please read the note on the back first fΪΚ 格 写 本 I) ir suspected A7 A7 Printed by the Central Laboratories of the Ministry of Economic Affairs of the Central Government Bureau of Quasi-Beige Consumer Cooperatives m * ________B7___ V. Description of the invention (8) A waveguide or an optical fiber is connected to the structure of each MMI waveguide Basically similar to the structure shown in Figure 2 except that at each end point it has been joined together. It can be seen from FIG. 4 that these endpoints include only one channel waveguide. Moreover, the respective short-side portions p, q are not perpendicular to the center line β of the channel waveguide. The reason is that unnecessary light in the MMI waveguide is refracted at this part of the structure 'and from there The cascade of two consecutively arranged MMI waveguides in which β has disappeared has the effect of reducing cross-talk. It is also feasible in this embodiment to include a kind of phase control element mentioned in the brief description of the present invention. Any required number of channel waveguides can be configured on these two MMI waveguides, although the channel waveguides are preferably two on one side and two on the opposite side. It is clear from the figure that the Bragg grating can be offset from the center of the MMI waveguide or be arranged on the center of the waveguide. FIG. 5 illustrates another embodiment of the improved optical wavelength selection device, in which two MMI waveguides can be directly combined β. As can be seen from FIG. 5, the MMI waveguide in this embodiment is gradually tapered on one side alone. 'While the passage waveguide system is arranged on this side, the respective long sides of the β MMI waveguide are parallel to each other between the two Bragg grids. The centerline of one MMI waveguide and the centerline of other MMI waveguides are parallel and laterally offset. In order to reduce the reflection of unnecessary light in the MMI waveguide, the ρ and q portions are angled in the respective MMI waveguide, and these portions are roughly the remainder of the aforementioned lateral parallel shift of the centerline. This embodiment may also include a phase control element of the kind mentioned in the brief description of the invention. Any required number of channel waveguides can be configured in the free ends of the respective MMI waveguides. The actual limitation related to this number is imposed by these MMI waveguides. 11- This paper applies to China National Standards (CNS) A4 specifications (210X297 mm) I ---- T-Ι-ΓΙ Packing ------ Order ------ Line (please read the note fi on the back first »fill in this note) A7 * " —_____—_ B7_ —__ 5. Description of the invention (9) Determined by the size of the tube. Another option for arranging the channel waveguides in the outward protrusions is that the refractive index of the MMI waveguides can be changed by connecting the appropriate channel waveguides, but the same effect is obtained, that is, The purpose of changing the optical path length in a waveguide is to compensate for mode-dependent phase offsets. This alternative is exemplified in Figure 6. In this embodiment, the refractive index of the MMI waveguide has increased in a rectangular region 60, which is directly adjacent to a pair of channel waveguides and the longitudinal centerline of the rectangle is coincident with the centerlines of the respective channel waveguides . By transforming existing materials in MMI waveguides by, for example, ultraviolet writing, a change in refractive index can be obtained. The type and size of the refractive index change have a decisive influence on obtaining this effect. This advanced device can be adapted to be made of materials such as quartz (SiO 2), polymer materials, some semiconductor systems, or lithium niobate (LiNb03), although quartz is preferred. It can be understood that the present invention is not limited to the above and exemplified embodiments, and may be modified in the following patent application parks. (Please read the note $ on the back / fill in this card first) ---- Installation ------ Printed by the Central Laboratories of the Ministry of Economy National Standard (CNS) A4 Specification (210X297)