| dc.description.abstract | 在資訊量爆炸的時代，光通訊已逐漸取代原先的電子訊號傳輸，成為不可或缺的方法，但目前技術尚未發展成熟，任何有關於光傳輸、光訊號調變元件之研究，對於未來之發展將給予莫大的支持及幫助。
其中，定向耦合器除了可以作為開關、頻率及偏振選擇之元件外，也可滿足光波導元件在強度分光上之功能，且如果將其設計製做在電光材料上，又可以透過電壓去調控輸出端之表現，快速且方便。
本研究在鈮酸鋰晶體上，利用模擬退火法設計出非週期性晶疇排列之結構。此結構在定向耦合器之耦合區域中，可藉由施加電壓的不同，改變定向耦合器的輸出表現，且表現有別於以往文獻中週期性交錯電極之定向耦合器。
在設計中，增加了元件之製程容忍度及調制電壓之容忍度，也增加的元件表現的自由度。利用以上的表現組合出電壓斷路器、1×4路由器、光源和邏輯閘(NAND,AND,XOR,XNOR,NOR,OR)，皆是具有實用性之設計，期待在未來可以實作出元件，並不斷地優化設計，讓其成為具有高競爭力之元件。 | zh_TW |
| dc.description.abstract | In the era of information explosion, optical communication is desired to replace electronic transmission because of the increase of the data-carrying capacity nowadays; however, it is not mature enough. And therefore researches, which are related with optical transmission and optical signal modulation devices, such as directional couplers, would give great support in the future.
The function of the optical directional coupler is not only the switch, the selective device of frequency and polarization, but also the amplitude divider. Moreover, the directional coupler, which is based on electro-optic (EO) crystal, can achieve a fast modulator by modulating the applied voltage.
In this study, the electro-optically switched directional couplers in APPLN (aperiodically poled lithium niobate) were designed by the AOS (aperiodic optical superlattice) technique with the aid of the simulated annealing (SA) optimization method. The split ratio based on the design can be manipulated by applying voltage along the crystal z axis and performances, which are compared with the periodical designs in the previous literatures, can be even improved.
The optimized APPLN structures can increase the tolerance for fabrication and working voltage, which allows the possibility of output performances being more flexible. Based on this advantage, we could further apply designs to practical applications, such as voltage circuit breaker, 1 × 4 signal router, integrated light source, and logic gates (NAND, AND, XOR, XNOR, NOR, OR). In the future, we expect to realize the optimized device to be a highly competitive device. | en_US |