Design And Simulation Of Diode Laser Array By Grating-External Cavity Spectral Beam Combining

Over the past decades,laser technologies have developed tremendously and are playing an increasingly important role in economic development in highly industrialized countries.However,the poor beam quality is still the main bottleneck limiting their further applications.In addition,many applications require high-power lasers,but the maximum output power of the current commercial single-tube diode laser is in the level of mW.Therefore,it is important to study how to improve the beam characteristics of high power diode laser array.In this paper,the technique of grating-external cavity spectral beam combining is used to shape the diode laser array by using ZEMAX.The system consists of a laser diode array,a collimating lens,a transmission len,a grating and an output coupler mirror,and the output beam is overlapped in the far field and the near field by the diffraction effect of the grating.In addition,the beam shaping systen allows the output beam to have the same beam quality as the individual emitting unit,and total power of all individual emitting unit.The structure and main contents of this thesis are as follows:(1)In this paper,the working principle and classification of diode lasers are described,and the main parameters,beam characteristics and beam quality evaluation methods of diode lasers are introduced in detail.(2)The principle of grating-external cavity spectral beam combining is introduced By using the diode laser array with the wavelength of 1060nm as an example,the beam characteristics,the beam quality,the incident angle and the individual emitting units' central wavelength are calculated in detail.(3)In the ZEMAX sequence mode,the first collimation system composed of the fast axis collimator(FAC)and the slow axis collimator(SAC)and the second collimation system composed of the double-focal lens are designed respectively.Simulation results show a good collimation effect.Besides,the transmission lens are designed with two glued lenses to reduce the aberration and make different beams focus on the grating.(4)In the non sequential mode of ZEMAX,the above two kinds of collimation system are simulated in the grating-external cavity spectral beam combining system,and good results are obtained Finally,The efficiency of the spectral beam combining system is 99.6%and 99.7%without considering the actual loss of the resonator and diffraction grating.In addition,the linewidth is 19.86nm,and the beam quality is similar to a single collimated emitting unit.