Liu Yu, Dong Yue, Xu Yin, Zhang Bo, Ni Yi
Appl Opt. 2022 Jan 10;61(2):580-587. doi: 10.1364/AO.446518.
A polarizer is used to eliminate undesired polarization states and maintain an orthogonal one. The polarizer we proposed is designed on a silicon nitride () on insulator platform to achieve low-loss operation at the 850 nm wavelength region. Compared with conventional polarizer structures, chirped subwavelength gratings (SWG) are introduced in the proposed device's main body to extend the wavelength band of the leakage mode, i.e., TM polarization state. Owing to the broadband nature of leakage mode, the operating bandwidth, which is defined as the wavelength region with extinction ratio (ER) higher than 20 dB, is increased dramatically. The simulation results show that the TE polarization state passes through the proposed polarizer with a high =46.24 and a low insertion loss ()=0.13 at 850 nm. A bandwidth broader than 171 nm is achieved with >20 and <1 over the wavelength region from 775 to 946 nm.
偏振器用于消除不想要的偏振态并维持正交偏振态。我们提出的偏振器是在绝缘体上氮化硅（）平台上设计的，以在850纳米波长区域实现低损耗运行。与传统偏振器结构相比，在所提出器件的主体中引入了啁啾亚波长光栅（SWG），以扩展泄漏模式（即TM偏振态）的波长带宽。由于泄漏模式的宽带特性，定义为消光比（ER）高于20分贝的波长区域的工作带宽显著增加。仿真结果表明，在850纳米处，TE偏振态以高=46.24和低插入损耗（）=0.13通过所提出的偏振器。在775至946纳米的波长区域内，实现了大于20且小于1的带宽超过171纳米。
