Research On Fiber-coupled Semiconductor Laser With KW Level Output Power

Fiber-coupled laser diodes,because of their small size,high electro-optical efficiency,and long lifetime,have been extensively used in solid or fiber laser pumping,material processing,scientific and medicine fields,etc.Due to the unique structures of diode laser,the beam quality is asymmetric in both axes direction,which limit its many direct applications.So the researches on beam shaping and fiber coupling technique for diode lasers,have evolved into a highlight.The paper is aimed to achieve a kW level fiber-coupled laser diodes prototype.By surveying the high power fiber-coupled diode laser on domestic and international,we have researched the existing beam shaping techniques.Based on the diode laser stacks parameters,we have conducted following work:(1)We introduced the semiconductor lasers.Analyzing the development status of fiber-coupled diode laser at home and abroad.Then the optical characteristics,basic principle,structure parameters,and the methods of evaluating beam quality are described.(2)We have designed a kW level fiber-coupled diode laser system based on the parameters of diode laser stack.Power scaling,beam shaping,and fiber coupling techniques for high-power diode laser stacks were used to couple the laser beam into a fiber with a core diameter of 800 ?m and an NA= 0.22,and simulated it by the Zemax sequential patterns.And then we have accomplished the mechanical structure design of prototype.(3)The experiments of k W level fiber-coupled diode laser system have been conducted.Coupled the laser beam of six diode laser stacks into a fiber with a core diameter of 1000 ?m and an NA=0.22,the output power could reached 2020 W.And the prototype could meet the demand of the industrial processes such as laser manufacturing and remanufacturing industry.(4)Based on the existing beam shaping methods,we proposed an innovative one-step cutting-rotating beam shaping technique based on the double total internal reflection to improve the beam quality in both axes direction.The beam shaping device has only one prism stack,which means the adjustment and manufacture will become more easily.We simulated a kW level fiber-coupled diode laser system based on the technique.The simulation results denote the high output power of fiber could achieve.