The Research On Laser Power Synthesis Technology Based On Semiconductor Laser

With the widespread application of laser technology in material processing,national defense security and other fields,the increase of laser output power and beam quality has attracted more and more attention of researchers.The single emitter diode lasers have the advantages of good beam quality and high reliability,but they are limited by the fact that the output power is difficult to increase.Therefore,the thesis studies the laser power synthesis technology based on multiple single emitter diode,mainly includes the following contents:Firstly,the thesis introduces the electrical and optical properties of semiconductor lasers,then discusses the measurement methods of several important laser parameters,such as laser spot size and divergence angle,and summarize the evaluation methods of beam quality.It is concluded that BPP is most suitable for beam quality evaluation in laser power synthesis field.Secondly,the thesis uses the ray trace function of ZEMAX software to simulate the output characteristics of the laser beam in a non-sequential mode,and uses the different types of lens to collimation design in the direction of the fast and slow axis respectively.By analyzing the divergence angle and beam quality,the most suitable lens for fast axis collimation is an aspherical lens,and the lens best suited for slow axis collimation is a planoconvex lens.Aiming at the problem of collimation error in the fast and slow axis directions,the influence of the six-degree-of-freedom alignment error of the fast-axis collimator and the slow-axis collimator on the beam collimation effect is simulated in the software,and the simulation results are quantitatively given.Thirdly,the thesis analyzes and discusses the coupling conditions to be satisfied when the laser is coupled into the fiber.The influence of different fiber diameters on the coupling efficiency and the output power density is discussed under the condition that the spot shape is mismatched with the core shape of the fiber end face.Focusing on the problem of the offset of the combined beam after the expanded beam focusing system at the focal point position,the effect of the divergence angle,the wavelength and the optical path on the coupling position and the spot size of the back focus are quantitatively analyzed.Finally,through the combination of optical design and space design,the spatial arrangement of single emitter diode lasers in the direction of the fast and slow axes is calculated and analyzed.After the analysis of the optical paths of the collimation system,beam combining system,beam expanding system,and coupling system,a 6-channel 5-Watt laser power synthesizing module is designed,and a laser with an output power of 25.6 watt at the end of the fiber is simulated.Then a 12-channel 10-watt laser power synthesizing module is designed based on the polarization combining technology,and an optical fiber output of 100.1 watt laser is simulated,and a 24-channel 10-watt laser power synthesizing module is designed based on the wavelength combining technology to achieve a fiber output of 190.1 watt laser.