近年來對於光學感測器與光學掃描器的發展具有高度的重視，其中光學探測與測距技術 (Light Detection and Ranging, LiDAR)更是其中重點研究之一，而其中快速掃描與積體化的LiDAR是未來的研究重點。“LiDAR on Chip”是目前積體化LiDAR的一個重要概念，而光學相位陣列(Optical Phase Array, OPA)便是其中一項能夠實現這個概念的技術，為了能夠具有較大的光束轉向角，則必須得將陣列天線的間距減小。由於波導間距過於緊密容易導致串擾現象(Crosstalk)。因此本論文將會深入的討論矽帶波導與光學天線之間如何降低耦合及相位串擾對於波束成形遠場之影響。
為了改善光學相位陣列間的耦合現象及串擾狀況且有效提升OPA之FOV，本論文藉由開發一個矽基微結構，矽帶光柵波導(Silicon-Ribbon grating waveguide)，加入至32通道之光學相位陣列，促使魚骨頭光柵波導天線間的串擾降低。藉由商業軟體Rsoft使用時域有限差分（Finite-Difference-Time-Domain, FDTD）模擬針對此結構進行深入探討，其中透過矽帶波導的加入使得光柵天線間之間距可以更為緊密達0.6μm來有效地提升OPA在Φ方向的可視場角，本研究之設計相較於傳統天線間距為1.2μm之OPA由原本之可視場角66度明顯地提升至95度，且Side lobe明顯降低約10dB，將雜光有效抑制並集束於main lobe上提升6dB，並透過將天線波導設計成對稱型雙向輸入且能量呈現線性衰減的形式來有效地提升其光柵有效長度藉此讓光斑在天線僅400μm之FWHM達到約0.24度，並透過雙向輸入形成兩光斑藉此在θ方向能夠進行雙點掃描有效地提升θ_z方向可視場角至30度。
本研究利用具矽帶陣列之8通道OPA晶片證明此結構在±30度的掃描內，光柵瓣仍然在40度以外的位置，產生大於70度的水平可視場角，且垂直掃描調製角度達約每奈米0.14度與理論模擬的單位波長的角度調制相符，且再透過基因演算法調製電壓的情況下，修正製成誤差所帶來的相位差，使得水平FWHM與理論相符合達到約11.9度，SMSR達到約10dB以上。

In recent years, the development of optical sensors and optical scanners has been highly emphasized in the light detection and ranging (LiDAR) research areas. The LiDAR with fast scanning rate and high integration is one of the essential technologies the researchers are focusing on. And the phased optical array (OPA) is an integrated approach to realize the concept of integrated LiDAR through "LiDAR on Chip." The pitch of the array antenna must be reduced to have a larger beam steering angle. The tight spacing of the waveguides can easily lead to coupling crosstalk. Therefore, this thesis will discuss reducing the coupling and crosstalk between the silicon wire-based optical phased array in beamforming.
To improve the coupling and crosstalk between optical phase arrays and effectively enhance the field of view (FOV) of OPA, we develop a silicon-ribbon-based grating waveguide to reduce the crosstalk between 32-channel fishbone grating waveguides. The finite-difference-time-domain (FDTD) simulation was utilized to investigate this structure in-depth. The pitch between the grating antennas could be tightened up to 0.6-μm by adding the silicon-ribbon waveguide to improve the OPA FOV in the horizontal Φ-direction effectively. Compared with the conventional antenna with 1.2-μm-spacing, the OPA in this study has significantly increased the FOV from 66 degrees to 95 degrees. The side lobe has been dramatically reduced by 10-dB. 6-dB has effectively suppressed the noise on the main lobe. The full width at half maximum (FWHM) of the antenna is about 0.24 degrees. The dual spot scanning in the vertical theta direction is achieved through the bi-directional input, effectively increasing the FOV up to 30 degrees.
An 8-channel OPA chip with a silicon ribbon array experimentally demonstrates that a horizontal FOV is more than 70 degrees, and the ±30-degree scanning is shown at a 40-degree vertical angle. The vertical modulation angle is about 0.14 degrees per nanometer, which is consistent with the theoretical calculation. The horizontal FWHM is 11.9 degrees, and its side mode suppression ratio is more than 10 dB.

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