| 摘要: | 矽光子學已成為光子積體電路PIC(Photonic Integrated Circuit)的重要技術之一。這種技術被期望可克服長途通信中數據傳輸頻寬瓶頸的解決方法。高速傳輸需求的增加也促進了在光網路中大量使用密集波長分波多工（DWDM）系統。氮化矽耦合共振腔光波導結構是一種具有傳播損耗低、訊息不失真、大頻寬和結構密集且尺寸盡可能微小的技術，可應用於濾波器、色散補償和光儲存器領域。
本論文選擇低損耗材料氮化矽，研究耦合共振光波導頻寬優化第二部分討論 典型的Add-drop環形共振腔與雙環型共振腔透過 OptSim Circuit 與 MATLAB 數值計算模擬。利 用這些模擬方法進行分析 模擬驗證，確保模擬更為精確。為了設計有效濾波器元件並討論在不同尺度下之雙環型共振腔，結果顯示不對稱環型共振腔有較窄的半高頻寬，因游標尺效(Vernier effect)有顯著較大的自由頻譜範圍。
論文第三部分主要討論耦合共振腔光波導設計改善方法，並討論兩種非對稱耦合共振光波導的尺度設計形式。模擬結果顯示，這一種非對稱耦合共振光波導的半高頻寬都比原本的耦合共振光波導提高了超過45%，表明非對稱的耦合共振光波導具有較寬的半高頻寬。此外，我們還深入討論了功率耦合係數與半高頻寬的關係。模擬結果顯示，半高頻寬與功率耦合係數呈現線性相關，這啟發了可以通過改善波導幾何結構或環腔設計來改善耦合共振光波導的半高頻寬。
在進一步的研究中，我們發現耦合共振光波導的功率耦合係數必須保持一定
的比例，以避免產生帶通波紋。此外，當環腔與環腔的功率耦合係數大於波導與環腔的功率耦合係數時，帶通濾波器也會產生大量波紋，從而無法為 有 效濾波器功能。綜上所述，改善耦合共振光波導的耦合係數，同時有助於避免波紋的產生進一步改善半高頻寬效益。
在研究中，我們還發現，光波導的損耗對於耦合共振光波導的設計和分析非常重要。分析結果顯示，光波導的輕微損耗有助於消除波紋，使得耦合共振腔光波導的表現接近於理想情況。此外，損耗與頻寬呈現反比趨勢。因此，在耦合共振光波導的設計和分析中，需要注意光波導的損耗對性能的影響。
本論文研究了耦合共振光波導頻寬優化的方法，探討新的設計方式以改善半高頻寬，進而提升抑制波紋效益。研究中使用Synopsys OptSim Circuit設計軟體，展示了CROW架構布局與模擬測試結果，以展現矽光子積體電路的潛力與可用性。根據研究結果顯示改善半高頻寬，進一步提高矽光子積體電路的性能。
;Silicon photonics has emerged as a pivotal technology within the realm of photonic
integrated circuits (PICs). This groundbreaking technology holds the potential to
overcome existing bandwidth bottlenecks in long distance communication through the
deployment of compact, integrated devices. The escalating demand for high speed data
transmission has precipitated the widespread adoption of dense wavelength division
multiplexing (DWDM) systems across optical networks. Among va rious material
options, silicon nitride stands out in the fabrication of coupled resonator optical
waveguides due to its inherent advantages: low propagation loss, distortion free
transmission, ample bandwidth, and compact form factor. These characteristic s make
silicon nitride waveguides well suited for applications in filter design, optical
modulators, and optical network infrastructure.
In this thesis, the author opts for the low-loss material, silicon nitride, to investigate the optimization of filter bandwidth based on coupled resonator optical waveguides (CROW). Initially, the thesis delves into the typical transmission response of add-drop ring resonators and double-ring resonators, leveraging OptSim Circuit and MATLAB for numerical calculations. Simulation results indicate that the bandwidth of the double-ring resonator can be enhanced, showing up to a 28% improvement compared to that of the conventional single-ring resonator. Subsequently, for the design of efficient filtering elements, the author examines double-ring resonators with varying design parameters. The findings reveal that asymmetric ring resonators possess a narrower half-width bandwidth and a significantly larger free spectral range, attributable to the Vernier effect.
Third,in this par t of the discussion, we further explore the design elements of coupled resonator optical waveguides by examining two designs of asymmetric coupled
resonator waveguides. Simulations reveal that these two asymmetric designs offer bandwidths up to 45 % greater than that of their symmetric counterparts.
Moreover, we delve into the relationship between the power coupling coefficient and the resulting bandwidth. A linear correlation emerges from our simulations,suggesting that enhancing waveguide coupling strength can lead to a significant increase in the bandwidth of the coupled resonator optical waveguides. This finding underlines the potential of optimizing waveguide coupling for the efficient enhancement of bandwidth in such systems
Furthermore, attention must be paid to the ripple effect in bandpass filters. This undesired phenomenon can be substantially reduced through careful optimization of the coupling coefficient. On the other hand, the inherent loss that optical waveguides exhibit is an influential facto r in the design process of coupled resonator waveguides.Precise adjustment of the waveguide loss parameters offers a method to not only mitigate the ripple but also facilitate the creation of an optimal bandpass filter. A notable observation from our stud y is the inverse proportionality between loss and bandwidth.This relationship presents an additional mechanism for achieving performance optimization in the design of coupled resonator waveguides
In summary, our proposed strategies for the optimization of
coupled resonator optical waveguides mark a significant step forward in the field. These methodologies present a powerful toolkit for boosting the bandwidth of bandpass filters based on Coupled Resonator Optical Waveguides (CROW). By refining the coupling coefficient and mitigating inherent waveguide loss through precise adjustments, we can notably enhance bandwidth and suppress the undesirable ripple effect.Our research also underscores the importance of understanding the inverse proportionality between loss and bandwidth, a relationship that adds another dimension to our optimization process.Looking forward, these advancements open up new avenues for improving the efficiency and functionality of optical communication systems, with potential implications for a broad array of applications in telecommunications and beyond |
