MEMS-Based Tunable Optical Filter

Tunable optical filter is an important component in modern optical communication systems and the field of sensors. It has become an inevitable trend to research and develop the small size, low cost, fast response, wide tuning range and polarization insensitive tunable optical filter. This paper presents a new structure of the tunable optical filter (TOF) about Micro-Electro-Mechanical-Systems (MEMS)-based technology. The device has simple structure, easy preparation, excellent optical performance and wavelength tunable continuously within the entire C-band. It will be have a good practical value.In this paper, it makes use of the dispersion characteristics of diffraction grating and angle adjustment features of MEMS mirror to achieve the function of wavelength selection. It effectively improves the performance of tunable optical filter when optical signal twice through the grating. The main contents of this paper include six parts: introduction, basic principles, device design, ZEMAX software simulation, laboratory testing and analysis, summary and prospect.In the first chapter, it describes the concept of optical filters firstly, introduces the working principle and characteristics of structure of several common optical filters, analyzes the principle and structure of MEMS technology and its applications in optical communication, advances MEMS-based tunable optical filter. In the second chapter, it from the filtering principle of grating, leads to the filtering principle of the MEMS tunable optical filter, analyzes the performance of the grating have influence on tuning range, spectral and other related parameters of filter, describes the transfer theory of Gaussian beam. In the third chapter, it from the relationship among the grating incident angle, MEMS turning angle and the spot size to detail design parameters of the specific structure of each component, calculates theory bandwidth and the analog bandwidth of computer software in this MEMS tunable optical filter. In the fourth chapter, it details simulation process, design procedures and the established entity model of the optical design software ZEMAX, and analyzes the final simulation results. In the fifth chapter, it carries out experiments by building the optical platform, does a detailed testing and analysis about insertion loss, wavelength dependent loss, polarization dependent loss and bandwidth of MEMS tunable optical filter, and comes to a conclusion to compare with the calculated value. In the sixth chapter, it summarizes the full text and makes the prospects.