M366077 五、新型說明： 【新型所屬之技術領域】 本案係為一種積體化之光學元件之應用，特別有關 於改變週期性分段波導之工作週期及其設計方法。 【先前技術】 近年來由於網際網路的進步，使得通訊頻寬的需求 || 急劇地增加，傳統以電流傳輸訊號的方法已無法承載 高容量訊號，必須要以光波傳輸光訊號以解決頻寬的 需求，這個結果因而促進了光通訊技術及積體光學快 速地發展。 在積體光學元件中，訊號是經由光波在光波導中傳 送，要將光從單一輸入端分配到多個輸出端時，如何 使光能夠均勻分配是非常重要的。一個1χΝ的分光 器用在光通訊網路上，是為了達到訊號均勻分配的目 > 的；對積體光學而言，則是用來將光訊號分配傳輸到 其他元件。而1x2的Y形分光器則是lxN分光器的基 ' 本單位，它常被用來作為光功率分配器、光開關、光 * 合成器等，主要的結構可分成分岔式分支波導與耦合 式分支波導兩大類，而分岔式分支波導又分成兩類， 一為對稱式Y形分支波導，另一為非對稱式Y形分支 波導。 3 M366077 而為了能夠得到較小的元件體積，就必須要有大角 度的分岔或彎曲波導結構，才能夠有效縮短元件的長 度，不過由於彎曲角度越大，相對通過彎曲波導的損 耗也越嚴重，導致分岔或彎曲角度受到限制，所以研 究如何能降低大角度彎曲波導的傳播損耗是相當重要 的。 因此有人提出運用週期性分段波導的技術，在光波 導系統中於傳播方向折射率隨著區塊波導週期而調變 所組成的γ型週期性區塊波導結構，依據週期性分段 波導原理提出使用週期性分段波導架構在γ型波導 上，可有效的降低損失功率，且同時縮短元件長度。 而本案經由適當的改變週期性分段波導的工作週 期（duty-cycle )，用以改變波導傳波方向的折射率， 使得折射率呈現線性降低的效果，即讓入射波由輸入 到週期性分段波導有較好的的模態匹配，以達到元件 縮小之目的。 【新型内容】 本案為在傳統Y型結構上做改變，即為一個輸入端 之功率平均輸出至兩個輸出端。當入射波由輸入端進 入後，接著會進入漸變波導（Taper waveguide)來幫 助模態尺寸轉換，達到功率分離的效果，一般適希望 它必須能夠防止散射，並以單模態在波導内傳播，而 長度盡可能越短越好，這是為了在傳波損耗和耦合效 M366077 率之間達到最佳化；本案即為在此架構上加入一週期 性區塊波導區，藉由控制週期性漸變波導的工作週 期，讓入射波由輸入到週期性分段波導有較好的的模 態匹配，使得其輸出功率提高。 【實施方式】 本新型之節構圖請參照第一圖，其元件之構成為一 傳統γ型結構搭配週期性分段波導所組成，首先由輸 入波導端（fTGj入射光波長信號，接著會經過漸變 波導段（FGV)和内部加入之週期性分段波導區 ，最後輸出至輸出波導段（FG0)，且輸入 波導段和輸出波導段需以單模態傳播，在週期性區塊 波導區可調整其工作週期得到比較理想之耦合效率， 此處定義工作週期即週期性分段波導的間隔（尸）和分 段週期（J)間之比值，數學表示式為尸“，且工作週 期會沿著傳播方向遞增，若以公式表示為 厂m=厂’ m=l，2 · · ·，及即為一開始所設的初始 變化量。 接著配合模擬說明，將可明白其操作原理。其中本 案選擇波導寬度（妒）為5//m，週期數20個之參數 來做模擬，觀察其傳輸率變化。 為了說明改變工作週期所造成的影響，首先模擬當 改變週期性分段波導的起始間隔（乃）時產生的變化， 如第二圖所示，角度為1度和1.5度時，週期性分段 5 M366077 波導的起始間隔越大時可得到比較高的傳輸率，即工 作週期越小越好，模擬角度在2度時，週期性分段波 導的起始間隔變化量從0//m〜0.22//m，當起始間隔 在0.05//m可得到最高的總傳輸率，模態轉換的效率 最好，其中總傳輸率變化量最高可到達10%，所以工 作週期的選擇是相當重要的。 為了能近一步了解它的各種變化，首先模擬角度改 變時，相對於總傳輸率。如第三圖所示，在傳統Y分 支波導結構，當半分支角低於1.25度時，總傳輸率會 呈現明顯的下降，這是因為模態受到不同程度的破 壞，而當半分支角度為1度時，大約會有79%的總傳 輸率會成為基本模態，剩下約30%的總傳輸率會轉換 成高階模態，1%的總傳輸率則會散射。不過在使用週 期性分段波導後，在1度的小角度時，模態比較不會 受到破壞，輸出功率明顯的增加，大概只有3%會轉 換成高階模態，1%的總傳輸率會散射。這是因為週期 性分段波導改變了波導折射率，使得模態能夠匹配， 防止了散射的發生。 而高性能的分支波導歸因於使用了高效能的分離 區，在小角度時，要成為基本模態且功率損失不高於 10%，傳統的Y分支波導結構是辦不到的，本按提出 的方法在Θ〜1.25度時，總傳輸率均可達90%以上， 遠優於傳統Y分支結構，並且傳播模態不會受到破 壞。經由第四A圖和第四B圖的模擬可更清楚呈現此 6 M366077 一特性，第四A圖和第四B圖分別顯示在分支角為 0.75度下，傳統γ型結構和週期性分段波導的場形分 佈；當光場經過漸變波段時，傳統γ型結構的模態轉 換會產生比較劇烈的震盪，如果是週期性分段波導;'結 構，當光場經過中間的分段波導區則會比較平緩，可 得到較理想的模態轉換。而第五A圖和第五B圖分別 顯不傳統Y型結構和週期性分段波導的光場分佈；可 發現當使料祕分段波導時，散射相對比較不明 顯，光束在波導内有比較好的傳播，能讓光侷限在其 中傳遞。 ' 不過當角度在1.25度〜4.5度時，傳統丫型結構的 傳輸率會比週期性分段波導結構好。為了解決這個問 題’探討當性分段波導的總長度做倍率放大時， 總傳輸率所發生的變化。如第六圖，取樣丨度角、2 度角和3度角。在i度角時’不管週期性分段波導總 長度增加或縮小，都不會得到較高傳輸率。不過若是 在2度角時’當長度增加後，總傳輸率最大約可提昇 24/〇，同樣在3度角時，總傳輸更可由原本27%增加 至60%，超過一半的提升。 以此結果，若將週期性分段波導增加2.5倍，重新 模擬角度改變相對於總傳輸率的變化，如第七圖所 不’對照第二圖可得$，在大角度的總傳輸率已有明 顯的提昇。 7 M366077 最後’以此週期性分段波導結構，也可應用在不同 彎曲結構上，如第八圖為直線型彎曲波導結構，第九 圖之圓弧塑彎曲波導結構，或第十圖之s型彎曲波導 結構’是-個非常具有發展性的結構。 【圖式簡單說明】 圖式簡單說明 第一圖為Y型週期性分段波導結構圖。 第二圖為模擬當改變週期性分段波導的起始間隔相對應的總 傳輸率變化。 第二圖為模擬角度改變時，傳統Y型結構和週期性分段波導 結構相對於總傳輸率的變化。 第四A圖為傳統γ型結構的場形分佈。 第四B圖為週期性分段波導的場形分佈。 第五A圖為傳統γ型結構的光場強度分佈。 第五B圖為週期性分段波導的光場強度分佈。 第六圖為模擬當週期性分段波導的總長度做倍率放大時，總 傳輸率所發生的變化。 第七圖為模擬週期性分段波導的總長度放大2.5倍時，對應 總傳輸率所發生的變化。 第八圖為直線型彎曲波導結構 第九圖為圓弧型彎曲波導結構 第十圖為S型彎曲波導結構 8 M366077 【主要元件符號說明】 奶％輸出波導段 FG/輸入波導段 奶A漸變波導段 ρχπ週期性分段波導區 Λ輸入功率 輸出功率 π波導寬度 週期性分段波導的總長度 J週期性分段波導的分段週期 尸7週期性分段波導的起始間隔 6»漸變波導彎曲角度M366077 V. New description: [New technical field] This case is an application of integrated optical components, especially related to changing the duty cycle of periodic segmented waveguides and its design method. [Prior Art] In recent years, due to the progress of the Internet, the demand for communication bandwidth|| has increased sharply. The traditional method of transmitting signals by current cannot carry high-capacity signals, and it is necessary to transmit optical signals by optical waves to solve the bandwidth. The demand, this result thus promotes the rapid development of optical communication technology and integrated optics. In integrated optical components, the signal is transmitted through the optical waveguide via light waves. When distributing light from a single input to multiple outputs, it is important to distribute the light evenly. A 1-inch splitter is used on the optical communication network for the purpose of evenly distributing the signal. For integrated optics, it is used to distribute the optical signal to other components. The 1x2 Y-shaped beam splitter is the base unit of the lxN optical splitter. It is often used as an optical power splitter, optical switch, optical* synthesizer, etc. The main structure can be divided into component branched waveguides and coupled. There are two types of branch waveguides, and the branching branch waveguides are further divided into two types, one is a symmetric Y-branch waveguide and the other is an asymmetric Y-branch waveguide. 3 M366077 In order to obtain a smaller component volume, a large angle bifurcation or curved waveguide structure is required to effectively shorten the length of the component, but the greater the bending angle, the more serious the loss through the curved waveguide. This leads to a limitation of the bifurcation or bending angle, so it is important to study how to reduce the propagation loss of the large-angle curved waveguide. Therefore, a technique of periodically segmenting a waveguide is proposed, in which the refractive index of the optical waveguide system is modulated by the patch waveguide period in the propagation direction, and the γ-type periodic block waveguide structure is constructed according to the principle of periodic segmented waveguide. It is proposed to use a periodic segmented waveguide architecture on the γ-type waveguide to effectively reduce the loss of power while shortening the component length. In this case, the duty cycle of the periodic segmented waveguide is appropriately changed to change the refractive index of the waveguide wave direction, so that the refractive index exhibits a linear decrease effect, that is, the incident wave is input to the periodic segment. Segment waveguides have better modal matching to achieve component reduction. [New content] This case is a change in the traditional Y-type structure, that is, the power of one input is output to two outputs on average. When the incident wave enters from the input terminal, it then enters the tapered waveguide to help the modal size conversion, achieving the effect of power separation. It is generally desirable that it must be able to prevent scattering and propagate in the waveguide in a single mode. The length should be as short as possible, in order to optimize the transmission loss and the coupling efficiency M366077 rate; in this case, a periodic block waveguide region is added to the structure by controlling the periodic gradient. The duty cycle of the waveguide allows the incident wave to have a good modal match from the input to the periodic segmented waveguide, resulting in an increase in output power. [Embodiment] Please refer to the first figure for the configuration of the novel section. The component is composed of a conventional γ-type structure and a periodic segmented waveguide. First, the input waveguide end (fTGj incident light wavelength signal, and then the gradation The waveguide segment (FGV) and the periodically segmented waveguide region added internally are finally output to the output waveguide segment (FG0), and the input waveguide segment and the output waveguide segment are required to propagate in a single mode, and are adjustable in the periodic block waveguide region. The working cycle is better than the coupling efficiency. Here, the duty cycle is defined as the ratio between the interval (the corpse) and the segmentation period (J) of the periodic segmented waveguide. The mathematical expression is the corpse, and the duty cycle will follow The direction of propagation is incremented. If the formula is expressed as the factory m=factor' m=l, 2 · · ·, and it is the initial change amount set at the beginning. Then, with the simulation description, the operation principle will be understood. The waveguide width (妒) is 5//m, and the number of cycles is 20 to simulate and observe the change of transmission rate. To illustrate the effect of changing the duty cycle, first simulate the change cycle. The variation of the initial interval of the segmented waveguide, as shown in the second figure, when the angle is 1 degree and 1.5 degrees, the higher the initial interval of the periodic segment 5 M366077 waveguide can be obtained. The transmission rate, that is, the smaller the duty cycle, the better. When the simulation angle is 2 degrees, the initial interval variation of the periodic segmented waveguide is from 0//m to 0.22//m, and the initial interval is 0.05//m. The highest total transmission rate is obtained, and the efficiency of modal conversion is the best. The total transmission rate variation can reach up to 10%, so the choice of duty cycle is very important. In order to get a closer look at its various changes, first simulate When the angle is changed, relative to the total transmission rate. As shown in the third figure, in the conventional Y-branch waveguide structure, when the half-branch angle is lower than 1.25 degrees, the total transmission rate will show a significant decrease because the modes are different. Degree of destruction, and when the half-branch angle is 1 degree, about 79% of the total transmission rate will become the basic mode, leaving about 30% of the total transmission rate will be converted into higher-order mode, 1% of the total transmission The rate will scatter, but using periodic segmented waveguides At a small angle of 1 degree, the modal comparison will not be destroyed, the output power will increase significantly, and only about 3% will be converted into a higher-order mode, and the total transmission rate of 1% will be scattered. This is because of periodic segmentation. The waveguide changes the refractive index of the waveguide so that the modes can be matched to prevent the occurrence of scattering. The high-performance branch waveguide is attributed to the use of high-efficiency separation regions, which become the basic mode and power loss at small angles. Above 10%, the traditional Y-branch waveguide structure can not be achieved. According to the proposed method, the total transmission rate can reach more than 90% at Θ~1.25 degrees, which is far superior to the traditional Y-branch structure and the propagation mode. The state is not damaged. The 6 M366077 characteristic can be more clearly presented through the simulations of the fourth A and the fourth B, and the fourth A and the fourth B are respectively displayed at a branch angle of 0.75 degrees, the conventional γ type. Structure and periodic segmental waveguide field distribution; when the light field passes through the gradual band, the modal transformation of the traditional γ-type structure will produce more severe oscillations, if it is a periodic segmented waveguide; 'structure, when the light field passes Intermediate segmented waveguide Will be relatively flat, it can be obtained an ideal modality conversion. The fifth A map and the fifth B graph respectively show the light field distribution of the conventional Y-shaped structure and the periodic segmented waveguide; it can be found that when the material is segmented, the scattering is relatively insignificant, and the light beam is in the waveguide. A better spread can limit the transmission of light. However, when the angle is between 1.25 and 4.5 degrees, the transmission rate of the conventional 丫-type structure is better than that of the periodic segmented waveguide structure. In order to solve this problem, the change in the total transmission rate occurs when the total length of the segmented waveguide is amplified. As shown in the sixth figure, the sampling angle, the 2 degree angle, and the 3 degree angle are sampled. At the i-degree angle, no higher transmission rate is obtained regardless of the increase or decrease in the total length of the periodic segmented waveguide. However, if the angle is increased by 2 degrees, the total transmission rate can be increased by about 24/〇, and at the same angle of 3 degrees, the total transmission can be increased from 27% to 60%, which is more than half of the increase. As a result, if the periodic segmented waveguide is increased by 2.5 times, the change of the angle change with respect to the total transmission rate is re-simulated, as shown in the seventh figure, the total transmission rate at the large angle has been obtained. There is a clear improvement. 7 M366077 Finally, this periodic segmented waveguide structure can also be applied to different curved structures, such as the eighth figure is a linear curved waveguide structure, the ninth figure is a circular curved bending waveguide structure, or the tenth figure s The curved waveguide structure 'is a very developmental structure. [Simple diagram of the diagram] Brief description of the diagram The first diagram is a Y-type periodic segmented waveguide structure diagram. The second figure is a simulation of the change in the total transmission rate corresponding to changing the initial interval of the periodic segmented waveguide. The second graph shows the variation of the conventional Y-structure and the periodic segmented waveguide structure with respect to the total transmission rate when the simulation angle is changed. The fourth A picture shows the field shape distribution of the conventional γ-type structure. The fourth B diagram is the field shape distribution of the periodic segmented waveguide. The fifth A picture shows the light field intensity distribution of the conventional γ-type structure. Figure 5B is a light field intensity distribution of a periodic segmented waveguide. The sixth figure is a simulation of the change in the total transmission rate when the total length of the periodic segmented waveguide is amplified by magnification. The seventh figure shows the change in the total transmission rate when the total length of the simulated periodic segmented waveguide is magnified 2.5 times. The eighth picture shows the linear curved waveguide structure. The ninth picture shows the circular curved waveguide structure. The tenth picture shows the S-shaped curved waveguide structure. 8 M366077 [Main component symbol description] Milk% output waveguide segment FG/input waveguide segment milk A gradual waveguide Segment ρχπ periodic segmented waveguide region Λ input power output power π waveguide width periodic segmented waveguide total length J periodic segmented waveguide segmentation period corpse 7 periodic segmented waveguide starting interval 6 » gradual waveguide bending angle