Abstract We demonstrate a novel biaxially tensile-strained Ge/SiGe multiple quantum well (MQW) electroabsorption modulator with low polarization dependence. The device is waveguide integrated and has a length of 900 μm. Suspended microbridge structure is utilized to introduce biaxial tensile strain to the Ge/Si0.19Ge0.81 MQWs. Light is coupled into and out of the waveguide through deeply etched facets at the ends of the waveguide. Both TE and TM polarized electroabsorption contrast ratios are tested by the use of polarization maintaining focusing lensed fiber and a linear polarizer. A polarization irrelevant contrast ratio of 4.3 dB is achieved under 0 V/2 V operation. Both simulations and experiments indicate that the demonstrated device has potential in waveguide integrated utilizations that have high requirements on polarization uniformity.

中文翻译：

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具有低极化依赖性的双轴拉伸应变 Ge/SiGe 多量子阱 (MQW) 电吸收调制器的演示

摘要 我们展示了一种具有低极化依赖性的新型双轴拉伸应变 Ge/SiGe 多量子阱 (MQW) 电吸收调制器。该器件是波导集成的，长度为 900 μm。悬浮微桥结构用于向 Ge/Si0.19Ge0.81 MQW 引入双轴拉伸应变。光通过波导末端的深蚀刻面耦合进出波导。TE 和 TM 偏振电吸收对比度均通过使用保偏聚焦透镜光纤和线性偏振器进行测试。在 0 V/2 V 操作下实现了 4.3 dB 的偏振无关对比度。模拟和实验都表明，所展示的器件在对偏振均匀性有很高要求的波导集成应用中具有潜力。