| Laser ignition is a high technology which puts the laser as a kind of “precision” ignition source and detonates or lights initiating explosive device through a transmission medium by using the high energy feature of laser. Adding optical switch to the transmission light path of the laser ignition system and using it as laser safety and arming device is conductive to the miniaturization of the system and the realization of multi-mode addressing ignition, it can also improves the security of the system.In this paper, a 1×2 MEMS optical switch based on electrostatic comb drive is presented according to the application requirements of laser ignition system. First, the light switching principle is analyzed. Then the operating principle of electrostatic comb drive and its lateral stability are discussed. The structure simulation and optimization are carried out by using ANSYS and CoventorWare and parameters of structure are picked up basing on that.Basing on the analysis of micromachining and fiber coupling technologies for the optical switch, the technological process is designed, of which the lithography, anodic bonding, high aspect ratio ICP etching and other key technologies are fully researched. A manual fiber coupling system is built, including a special base for 1×2 fiber coupling and the coupling of the optical switch chip are realized by using it.The design drive circuit for optical switch is done then, after which prototypes are successfully produced. According to performance and environmental adaptability requirements of the laser ignition system, the insertion loss, isolation, switching time and other performance index of these prototypes are texted, then the high-low temperature test, shock and vibration test, life test are conducted.The actuated displacement reaches 110 m, the insertion loss is less than 1.5dB, switching time is less than 1ms and the isolation is more than 50 dB, which meet the application requirements of laser ignition system. |
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