分析了基于法布里珀罗腔的微光机电系统可调谐滤波器中,空气腔厚度与峰值波长间的关系。微光机电系统中,空气腔的厚度一般在一个波长附近,因此腔的干涉级数较小,两边反射镜的反射相位对峰值波长的影响比较大。从反射相位出发,推导出了基于这种结构的可调谐滤波器中空气腔厚度和谐振波长之间的线性关系,并通过数值计算进行了验证。分析了影响滤波器调谐灵敏度的因素,构成介质反射镜的薄膜材料的高低折射值以及薄膜堆的层数都能改变线性系数的值。最后估算了一定波长范围内这种线性关系的误差。

The relation between the air gap thickness and the peak wavelength in micro-optical electromechanical system (MOEMS) optical tunable filter based on Fabry-Perot etalon is discussed. In the devices based on MOEMS, length of the air cavity is about one wavelength, so the phase shift on reflection of the dielectric reflector plays a crucial role in the low interference order. From the phase shift, the linear relation between the air gap thickness and the peak wavelength is presented and then proved by numerical computation. The refractive index of thin films and the number of stacks constructing the reflector that influence the tunable sensitivity are analyzed. At the end, error in a specified wavelength range is estimated.