A Study of Mach–Zehnder Interferometer Type Optical Modulator Applicable to an Accelerometer
A Study of Mach–Zehnder Interferometer Type Optical Modulator Applicable to an Accelerometer
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适用于加速度计的马赫-曾德尔干涉仪型光调制器的研究
DOI：
10.1143/jjap.50.04dg14
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发表时间：
2011
影响因子：
1.5
通讯作者：
S. Yokoyama
中科院分区：
文献类型：
--
作者：
Masato Suzuki;Tomokazu Takahashi;S. Aoyagi;Y. Amemiya;Masataka Fukuyama;S. Yokoyama
研制了一种基于微电子机械系统(MEMS)技术的新型马赫-曾德尔干涉仪(MZI)型光调制器。在该光调制器中，MZI中的两个分支波导中的一个具有浮动波束结构(气桥型)。此外，支撑验证质量的悬臂梁与浮动光波导相交。当由加速度引起的惯性力施加到验证质量时，浮动波导被扩展并且MZI的输出被调制。因此，这种光调制器将在未来的加速度计中得到应用。为了降低多模干涉(MZI)中浮动波导与悬臂梁相交处的光损耗，将多模干涉(MMI)波导与浮动波导串联，并将悬臂梁与MMI波导交叉连接。通过光学模拟和力学模拟，分别对MMI光波导进行了优化设计，并估算了浮动光波导在外力作用下的偏转。所提出的光调制器是通过对由晶体硅制成的绝缘体上硅(SOI)晶片的顶层进行电感耦合等离子体(ICP)刻蚀来制作的。调制器中的浮动波导是通过去除其底层掩埋的SOI氧化物(BOX)层而形成的。作为评估的结果，我们成功地通过在悬臂上施加力来改变MZI的输出。然而，调制比预期值要小。改进惯性力的调制和检测是下一步的工作。
A novel Mach–Zehnder interferometer (MZI)-type optical modulator based on micro electro mechanical systems (MEMS) technology is developed in this study. In this optical modulator, one of two branched waveguides in the MZI has a floating beam structure (air-bridge type). Additionally, a cantilever supporting a proof mass intersects with the floating optical waveguide. When an inertial force due to acceleration is applied to the proof mass, the floating waveguide is expanded and the output of the MZI is modulated. Therefore, this optical modulator will be applicable to an accelerometer in the future. To decrease optical loss at the intersectional point between the floating waveguide and the cantilever in the MZI, the multi-mode interference (MMI) waveguide is serially connected with the floating waveguide and the cantilever crosses to the MMI waveguide. An optimization of the MMI waveguide and an estimation of deflection of the floating waveguide due to applying force are carried out by using optical and mechanical simulation, respectively. The proposed optical modulator is fabricated by inductively coupled plasma (ICP) etching of the top layer of a silicon-on-insulator (SOI) wafer, which is made of crystal Si. The floating waveguide in the modulator is formed by removal of its underlying buried oxide (BOX) layer of SOI. As a result of evaluation, we have succeeded in changing the output of the MZI by applying a force to the cantilever. However, the modulation is smaller than the expected value. Improvement of the modulation and detection of the inertial force due to the applied acceleration are future tasks.