在本研究中，我們利用光跡模擬研究羅倫圓光柵的分光晶片。為了使繞射光線易與影像感測器耦合，我們在基板上加入一個將45度的反射面，使光束由垂直方向轉為水平方向。在光跡模擬中，於各波長主光軸上設置了一系列的偵測面，藉由偵測面之斑點圖的分析，得到各別波長的聚焦縱深。
此系統波長範圍由380nm到980nm，波長解析度可達1.4nm。波長準確度可達每像素0.05nm (pixel size 1.75μm)及0.1nm (pixel size 4.2μm)。影像感測器對分光晶片的組裝容忍度，可由全波段的聚焦縱深得到，約為1mm。羅倫圓光柵系統嵌入高反射率的平行波導，以防止光通量流失。模擬結果顯示，在100%的繞射效率及完美反射平面波導的條件下，可達到70%的光通量。波長範圍由380nm到980nm的影像區域為5mm×1.5mm，剛好落在CMOS感測器的範圍內。
本系統將分光晶片微縮至1.5cm×3.3cm×0.12cm，且在380nm到980nm範圍內可維持接收端的高光學訊號品質。本論文設計的晶片，可經由先進的光蝕刻技術達到量產，長聚焦縱深的設計可使分光晶片與CMOS感測器達到快速組裝的目的。

In this study, we realized a wavelength dispersion chip base on the design of Rowland circle grating geometry through a ray tracing simulation. A slanted slop is added on the wafer to redirect the diffraction beam to the upward direction for the easy coupling with an image sensor, which is used to acquire the spectrum. In the ray tracing, a series of detectors are positioned along the diffracted primary beam axis for the designed wavelength. The spot diagram of each detector is analyzed to obtain the beam waist. By analyzing the beam waist distribution along the primary optical axis, we are able to calculate the Depth of Focus (DoF) for each wavelength.
The designed wavelength range of this system is from 380nm to 980nm with a spectral resolution of 1.4nm. The wavelength accuracy reaches 0.05nm per pixel for a pixel size of 1.75μm and 0.1nm per pixel for a pixel size of 4.2μm. The DoF for the entire wavelength range is about 1mm. This also indicated a tolerance of 1mm for the assembly of the image sensor to the chip.
The Rowland circle grating system is embedded inside a slab waveguide with high reflectivity surface to preserve the photon flux. The simulation result showed that 70% of the incoming photon flux is collected by the image sensor based on a 100% diffraction efficiency and a perfect reflector slab waveguide. The image area for the 380nm to 980nm wavelength range is 5mm×1.5mm, which is about the dimensions of a CMOS image sensor.
The chip size is reduced to 1.5cm×3.3cm×0.12cm while maintaining a wide spectral range (380nm-980nm) with a reasonably good spectral resolution (1.4nm). With the use of a CMOS image sensor, the spectral accuracy is better than 0.1nm. The chip can be mass produced by modern advanced lithographic process and the design is also optimized for easy integration with the image sensor.

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