Low-loss polysilicon subwavelength grating waveguides and narrowband Bragg reflectors in bulk CMOS
Low-loss polysilicon subwavelength grating waveguides and narrowband Bragg reflectors in bulk CMOS
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DOI：
10.1364/oe.381894
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发表时间：
2020-03-16
期刊：
影响因子：
3.8
通讯作者：
Lee, San-Liang
中科院分区：
文献类型：
--
作者：
Hung, Yung-, Jr.;Tang, Cheng-Tse;Lee, San-Liang
多晶硅条形波导的高传输损耗限制了体CMOS光子功能器件的性能。基于零工艺变化的方法，我们成功地降低了多晶硅波导的传播损耗从112 dB/cm到只有38 dB/cm的波导几何形状的第一次单独工程。低传播损耗归因于使用亚波长光栅（SWG）波导设计的体多晶硅的0.09的显著降低的光学重叠因子。这些发现促使我们在体CMOS中展示基于SWG的窄带包层调制布拉格反射器，其提供1.63 nm的半高宽（FWHM），24.5 dB的消光比和27.3 pm/℃的降低的温度灵敏度。通过减小光栅耦合强度，还实现了将半高宽进一步减小到0.848 nm。我们相信，在这项工作中取得的成就验证了一个有前途的设计路径，实际的光子电子应用在散装CMOS。(C)根据OSA开放获取出版协议的条款，2020年美国光学学会
The performance of a photonic functional device in bulk CMOS has been limited by the high propagation loss in polysilicon strip waveguide. Based on the zero-process-change methodology, we successfully reduce the propagation loss of polysilicon waveguide from 112 dB/cm to only 38 dB/cm by solely engineering the waveguide geometry for the first time. Low propagation loss is attributed to a significantly reduced optical overlap factor of 0.09 to bulk polysilicon using subwavelength grating (SWG) waveguide design. These findings prompt us to demonstrate a narrowband SWG-based cladding-modulated Bragg reflector in bulk CMOS, which provides a full-width at half maximum (FWHM) of 1.63 nm, an extinction ratio of 24.5 dB, and a reduced temperature sensitivity of 27.3 pm/degrees C. Further reducing the FWHM to 0.848 nm is also achieved by decreasing the grating coupling strength. We believe the achievements made in this work validate a promising design path towards practical photonic-electronic applications in bulk CMOS. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement