由於光的先天特性，以光子為介質來傳送訊號可以使傳送速度與頻寬
大幅提昇，利用此優異性質，可以使得模組與模組/晶片與晶片間訊號的
傳遞以更有效率的方式進行。因此，積體光學被視為是下個世代的眾多新
興技術之一，並且在現實生活中的許多應用像是電信、資料處理、消費性
電子等等也扮演了重要角色。光的傳播過程中，在光波導交叉與彎曲的地
方會有繞射與折射的現象發生。不像傳統的電子積體電路，光子積體電路
尚未有一個較良好的訊號修復機制與能力，這也使得光波導繞線成為設計
光子積體電路的瓶頸之一。
關於這個問題，現有研究的解決方法為利用固有的排序演算法為基礎
去做繞線，以此來確保交叉數為最小值，並且加入了一些限制，希望達到
減少轉彎次數的目的，然而，此方法並沒有很有效地降低轉彎次數，因為
這種單純的排序機制並加入一些限制的方法較沒彈性，可能反而導致大角
度的轉彎數變多。因此，針對此種光波導繞線問題我們開發了一個整數線
性規劃的模型，同時考慮交叉個數與轉彎角度所帶來的損失，以及盡量減
少所需面積。並且藉由一個切割技巧，將原本的問題切成更小的問題來減
低時間複雜度。實驗結果顯示，我們提出來的這個方法能夠非常有效率地
降低訊號損失以及面積使用量。

Due to the superior nature of light, data transfer from module-to-module/chip-
to-chip in photonic integrated circuit (PIC) could be accomplished in a more
efficient way. Therefore, integrated optics is regarded as one of the most emerg-
ing technologies in next generation and plays an important role in several real-
world applications such as telecommunication, information processing, ......,
etc. During light propagation, diffraction and refraction may occur because of
the impact of waveguide crossing and bending, respectively. Unlike electronic
integrated circuits (EIC), PIC lacks the inherent signal restoration capabilities
of static-CMOS. Therefore signal loss is unavoidable and is considered as the
bottleneck of waveguide routing in PIC. Existing works utilized the inherent
sorting-based techniques with some revision to maintain the crossing minimal.
Also several constraints are imposed in expection of reducing the number of
bending. However, the sorting-based technique with some constraints imposed
cannot effectively reduce the signal loss. As a result of the inflexibility of this
routing mechanism, the number of sharp bendings may rather increase, which
results to more attenuation of transmitted signal accordingly. We develop an
Integer Linear programming (ILP) model for waveguide routing algorithm to
simultaneously minimize the impact of waveguide crossing, bending, and the
number of routing tracks. Moreover, a crossing-driven partitioning approach
is adopted to further reduce the time complexity of ILP model. Experimental
results show that our proposed approach is very effective on improving both
the signal loss and area utilization.

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