Grating-Coupled Silicon-on-Sapphire Polarization Rotator Operating at Mid-Infrared Wavelengths
Grating-Coupled Silicon-on-Sapphire Polarization Rotator Operating at Mid-Infrared Wavelengths
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DOI：
10.1109/lpt.2019.2896560
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发表时间：
2019-03
影响因子：
2.6
通讯作者：
A. Rostamian;Joel Guo;S. Chakravarty;Hai Yan;Chi-Jui Chung;E. Heidari;Ray T. Chen
中科院分区：
文献类型：
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作者：
A. Rostamian;Joel Guo;S. Chakravarty;Hai Yan;Chi-Jui Chung;E. Heidari;Ray T. Chen
我们提供了一个实验演示的中红外偏振旋转器的硅上蓝宝石平台上的中红外波长为4.55 μ m $，使量子级联激光器（QCL）和探测器的集成与开槽光子晶体波导（PCW）气体传感器的片上光学光谱应用。偏振旋转器对于将优先横向磁（TM）偏振光从QCL转换为横向电（TE）偏振以与优先TE引导开槽PCW传感器接口至关重要。偏振旋转器由绝热锥形模式转换器、移相器和多模干涉仪组成，所述多模干涉仪有效地将能量从输入的基本TM 00偏振转换为一阶TE 10偏振，然后将一阶TE 10偏振转换为基本TE 00模式。偏振选择性亚波长光栅耦合器被设计和制造为有效地将所设计的波长处的TE或TM偏振耦合进和耦合出偏振旋转器器件，以用于有效的器件表征。模拟了TM 00-TE 10转换效率为100%。移相器中的制造公差导致两个输出臂之间的测量输出TE 00偏振光的实验性80：20分光比。
We provide an experimental demonstration of mid-infrared polarization rotators built on a silicon-on-sapphire platform at the mid-infrared wavelength of $4.55~\mu \text{m}$ to enable integration of quantum cascade lasers (QCLs) and detectors with slotted photonic crystal waveguide (PCW) gas sensors for on-chip optical spectroscopy applications. The polarization rotators are essential to convert the preferentially transverse magnetic (TM) polarized light from a QCL to transverse electric (TE) polarization to interface with the preferential TE-guiding slotted PCW sensors. The polarization rotator consists of an adiabatic-tapered mode converter followed by a phase shifter and a multimode interferometer that effectively transfers energy from an input fundamental TM00 polarization to a first-order TE10 polarization that is then converted to the fundamental TE00 mode. Polarization-selective sub-wavelength grating couplers are designed and fabricated to effectively couple TE or TM polarizations at the designed wavelengths into and out of the polarization rotator device for efficient device characterization. TM00–TE10 conversion efficiency of 100% is simulated. Fabrication tolerances in the phase shifter result in an experimental 80:20 splitting ratio of the measured output TE00-polarized light between two output arms.