反射型变周期光栅透镜的性能研究

本文首先对各种集成光学透镜作了介绍,并对它们的优缺点进行了比较。 其次,本文对反射型变周期光栅透镜(RCGL)的原理和设计给予了详细的讨论,而且对RCGL的衍射效率和焦斑性质在理论上进行了较为彻底的研究。理论表明。RCGL的性能因光栅齿形和齿高的不同而不同,其中,以锯齿形齿的RCGL效果最好。无论何种齿形RCGL,如果齿高不理想,可失去聚焦效应。 我们制作了适用于扩Ti:LiN_bO₃波导的RGGL,它是以Si片为衬底,焦距为15mm,光栅面积为1.5mm×1.5mm。 实验结果表明:所制作的RCGL效果良好,衍射效率为14.4%,焦斑宽度(-3dB)为11μm,焦距值与设计符合良好。

A STUDY OF PERFORMANCE OF THE REFLECT-TYPE CHIRPED GRATING LENS

At first, various kinds of lenses used in integrated optics have been introduced and compared-with each other.Secondly, the principle of designing method of the reflect-type chirped grating lens (RCGL) has been discussed. After that, the diffraction efficiency and the character of the focal spot of RCGL have been almost thoroughly studied theoretically. The theory tell that the quality of RCGL relies on the shape of the grating teeth and the height of the teeth.If the height of the teeth is not well controlled, every kind of the RCGL may lose the focusing function.We have made RCGL which suits to Ti: LiN_bO₃ waveguide, the RCGL was fabricated on silicon substrate, the focal length is 15mm, the grating area is 1.5mm×1.5mm.The experiment express that the quality of the RCGL made by us is good the diffrac-tion efficiency is 14.4%, the width of the focal spot (-3dB) is 11μm,the focal length accords with the design very well