The design, modeling, micro-fabrication, and characterization of an ultra-broadband Ge-on-Si waveguide polarization rotator are presented. The polarization rotator is based on the mode evolution approach where adiabatic symmetric and anti-symmetric tapers are utilized to convert from the fundamental transverse magnetic to electric mode. The device is shown to be extremely fabrication tolerant and simple to fabricate. The fabricated devices demonstrate a polarization extinction ratio of ≥15 dB over a 2 μm bandwidth (9–11 μm wavelength) with an average insertion loss of <1 dB, which is an order of magnitude improvement compared to previously demonstrated devices. This device will provide polarization flexibility when integrating quantum cascade lasers on-chip for mid-infrared waveguide molecular spectroscopy.

中文翻译：

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超宽带中红外Ge-on-Si波导偏振旋转器

介绍了超宽带Ge-on-Si波导极化旋转器的设计，建模，微制造和表征。极化旋转器基于模式演化方法，其中绝热对称和反对称锥度用于从基本横向磁模式转换为电模式。该装置显示出极高的制造公差并且易于制造。所制造的装置证明≥15分贝在2的偏振消光比μ米带宽（9-11 μm波长）的平均插入损耗<1 dB，与先前展示的设备相比，数量级提高了。当在片中集成量子级联激光器用于中红外波导分子光谱学时，该设备将提供偏振灵活性。