Miniature Fabry-Perot Interferometer

本项目将利用法布里-珀罗涉术开发一种新型的角度传感器。这种方法特别吸引人，因为法布里-珀罗涉仪的角灵敏度与标准具的宽度成正比。因此，可以通过扩大标准具来使其更加敏感。例如，一个10毫米宽的标准具，在0.63微米的波长下，入射角度每改变50微弧度，就会产生一个完整的条纹。这种角度灵敏度可以用来测量引起旋转的次要现象，如振动和加速度。传统的法布里-珀罗标准具是经过抛光的玻璃板，其平坦度和平行度保持在高度的公差范围内。这一过程既昂贵又耗时。该项目将使用另一种方法来制造法布里-珀罗标准具，并使用波导微制造技术。这种方法具有明显的经济优势，因为当批量生产时，所得到的微型传感器将比传统的传感器便宜。本项目旨在确定微加工技术在生产性能与玻璃微标准具相当的半导体微标准具方面的有效性。光刻技术将被用来定义波导结构上的标准具。新的配置将允许波导内部的传播角度连续变化，因此它可以用作角度传感器。

This project will use Fabry-Perot interferometry to develop a novel angular sensor. This approach is particularly attractive because the angular sensitivity of a Fabry-Perot interferometer is proportional to the width of the etalon. Hence, it can be made more sensitive by widening the etalon. A 10 mm wide etalon, for example, yields a whole fringe for every 50 micro-radians of change in the angle of incidence at a wavelength of 0.63 micron. This angular sensitivity can be used to measure secondary phenomena that induce rotation such as vibration and acceleration. Conventional Fabry-Perot etalons are polished slabs of glass whose flatness and parallelism are maintained to a high degree of tolerance. This process is costly and time consuming. This project will use an alternative way of fabricating Fabry-Perot etalons with the use of waveguide microfabrication technology. There are distinct economic advantages to this approach because the resultant micro-sensor will be cheaper than the conventional one when mass-produced. This project aims at determining the effectiveness of the microfabrication techniques at producing semiconductor micro-etalons whose performance is comparable to that of the glass ones. Lithographic techniques will be used to define the etalons on the waveguide structure. The new configuration will allow the angle of propagation inside the waveguide to vary continuously so that it can be used as an angular sensor.