| With the development of science and technology,tunable diode lasers have been getting great attention.Comparing with other tunable laser technology,tunable diode Lasers have a lot of advantages,such as compact structure,large tuning range,narrow linewidth and so on.Tunable diode lasers have been used in manv scientific fields.There are many applications in spectrum analysis,laser distance measuring,and atmospheric pollution detection.External Cavity Tunable Diode Laser based on MEMS electrostatic rotary actuator is a very popular research in Tunable Diode Lasers,because it has compact structure,small size and wide angle of tuning,and single longitudinal mode laser output.For this type of laser,the most important part is the design of MEMS rotary actuator that drives the mirror or grating moving according to the specific demands of this laser.There are still some problems in the current MEMS rotary actuators,such as the limitation of the rotation angle,high voltage,and mode hopping.Therefore,based on the existing research.we do some research related on MEMS electrostatic rotary actuators for External Cavity Tunable Diode Laser and the research results are presented in this thesis.The research contents of this thesis are summarized as follows:(1)Based on the detailed analysis of the principle of MEMS single rotary comb drive,we builds a MEMS single rotary comb drive model using COMSOL Multiphysics,simulates the structure of MEMS single rotary comb drive and analyzes its rotation characteristics in this thesis.On this basis.a series of MEMS single rotary comb drive models with different tooth gap,tooth width,beam length and tooth curvature are built.These parameters are simulated and analyzed one by one.and the influence of' these parameters on structural rotation is discussed,which provides the optimal rotary comb drive parameters and optimization for MEMS comb actuator rotating around a virtual pivot point applied to External Cavity Tunable Diode Laser.(2)We proposes a MEMS symmetric actuator with bulge comb drive applied to External Cavity Tunable Diode Laser in this thesis.Firstly,MEMS single rotary bulge comb drive is analyzed,and MEMS single rotary bulge comb drive model is built and simulated.The simulation results show that bulge comb drive effectively reduces the driving voltage.On this basis,the parameters of the bulge comb drive are further modeled,simulated and analyzed,and the influence of these parameters on the rotation is discussed.Secondly,an improved MEMS symmetric actuator applied to External Cavity Tunable Diode Laser is proposed,and its principle is analyzed.The actuator provides a large rotation angle around a virtual pivot point under a narrow structure.At the same time,considering the advantages of bulge comb drive,a MEMS symmetric actuator with bulge comb drive is proposed.The proposed structure is modeled,simulated and analyzed,and the parameters and structure are continuously optimized.Finally,the MEMS symmetric actuator with bulge comb drive with displacement of 2500?m between the virtual pivot point and the farthest arc truss,voltage of 52 V and rotation of 2.5° is obtained.(3)We proposes a MEMS sector actuator with bulge comb drive for External Cavity Tunable Diode Laser in this thesis.Firstly,the principle of MEMS sector actuator rotating around a external virtual pivot point is analyzed in detail,which can provide a large rotation angle.Meanwhile,combined with the characteristics of bulge comb drive,a MEMS sector actuator with bulge comb drive is proposed.Then the proposed structure is modeled,simulated and analyzed,and the parameters and structure are continuously optimized.Finally,the MEMS sector actuator with bulge comb drive with displacement of 3200 ?m between the virtual pivot point and the farthest arc truss,voltage of 140 V and rotation of 3° is obtained.(4)We proposes a MEMS symmetric actuator with zipper comb drive applied to External Cavity Tunable Diode Laser in this thesis.Firstly,MEMS single rotary zipper comb drive is analyzed,and the model of MEMS single rotary zipper comb drive is built and simulated.The simulation results show that zipper comb drive can effectively increase the rotation angle when the structure size is fixed.On this basis,the parameters of zipper comb drive are further modeled,simulated and analyzed,and the influence of these parameters on the rotation is discussed.Based on the analysis of the principle of MEMS symmetric actuator,a MEMS symmetric actuator with zipper comb drive is proposed.The proposed actuator is modeled,simulated and analyzed,and the parameters and structure are continuously optimized.Finally,the MEMS symmetric actuator with zipper comb drive with displacement of 2500?m between the virtual pivot point and the farthest arc truss,voltage of 262 V and rotation of 3.7° is obtained.(5)This thesis proposes a MEMS sector actuator with zipper comb drive for External Cavity Tunable Diode Laser.Based on the analysis of zipper comb drive parameters and the principle of MEMS sector actuator rotating around a virtual pivot point,a MEMS sector actuator with zipper comb drive is proposed,which is modeled,simulated and analyzed.The simulation results show that zipper comb drive has less optimization effect on MEMS sector actuator.The innovation of this thesis is mainly as follows:(1)In order to reduce high driving voltage of MEMS actuators,we apply bulge comb drive to MEMS symmetric actuator rotating around a virtual pivot point for the first time,and working tooth gap is reduced to 1 ?m.Thus,MEMS symmetric actuator with bulge comb drive is designed and applied to External Cavity Tunable Diode Laser with mode-hop free tuning and narrow linewidth.The proposed actuator can rotate 2.5° around the virtual pivot point on both sides by applying voltage of 52 V.Compared to existing MEMS actuators rotating around a virtual pivot point,which require voltage of several hundred volts,the proposed MEMS symmetric actuator with bulge comb drive greatly reduces driving voltage and structure width.(2)In order to reduce high driving voltage of the MEMS actuators and avoid the influence of actuator for External Cavity Tunable Diode Laser,we apply bulge comb to MEMS sector actuator rotating around a virtual pivot point for the first time,so that the actuator can rotate around a external virtual pivot point and reduces working tooth gap.The MEMS sector actuator with bulge comb drive designed for External Cavity Tunable Diode Laser with mode-hop free tuning and narrow linewidth can rotate 3° around a external virtual pivot point on both sides by applying voltage of 140 V.Compared to existing MEMS actuators that rotate around a virtual pivot point,the proposed MEMS sector actuator with bulge comb drive can avoid the influence of actuator for External Cavity Tunable Diode Laser and effectively reduce driving voltage.(3)In order to obtain a larger rotation angle,we first apply zipper comb drive to MEMS symmetric actuator rotating around a virtual pivot point for the first time by shortening inner tooth length.The MEMS symmetric actuator with zipper comb drive designed for External Cavity Tunable Diode Laser with mode-hop free tuning and narrow linewidth can rotate 3.7° around a virtual pivot point on both sides by applying voltage of 262 V.Compared with the existing MEMS actuators rotating around thevirtual pivot point,which maximum rotation angle is 3°,the proposed MEMS symmetric actuator with zipper comb drive further increases rotation angle to 3.7°. |
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