Study Of Micro Programmable Grating Basing On MEMS Technology

A traditional diffraction grating consists of fixed reflecting (or transmitting) elements separated by a distance comparable to the target wavelength of light. But with the rapid development and wide application of gratings, the traditional ones can no longer meet the need in some fields such as physics, astronomical, biological, chemical etc. Gratings with the tunable structure are expected. Micro programmable grating is developed based on MEMS technology, this grating consists of an array of flat, closely packed micro beams. Each of these beams can be individually positioned vertically in an analog fashion using electrostatic actuation. Besides spectral analysis, Micro programmable grating will be very important in optical telecommunication. In this thesis, the model of a micro programmable grating was designed and some simulations were made. In addition, several key technologies about the micro programmable grating design were explored.Firstly, the diffractive characteristics of micro programmable gratings were studied, which were dependent on the number and vertical positions of micro beams in each diffraction cell.Secondly, the beam that can extend the working range of the micro programmable grating whose stroke is limited by Pull-in instability was designed, and it can travel across the full gap yet. This kind of beam would better the diffractive performance of micro programmable grating.Thirdly, the mechanical characteristics of micro beams were analyzed. In the analysis, analytical and numerical methods were used to perform static analysis, modal analysis, and transient analysis.Finally, the corresponding microfabrication process and layout of some kinds of micro programmable grating were designed, respectively. And these gratings were fabricated successfully in the Lab of NWPU (Northwestern Polytechnical University).