Design On High-brightness Coupling Semiconductor Lasers With 50?m Small Core Fiber

With the development of technique in laser beam cutting,the requirement in fiber coupling technique of semiconductor lasers is increasingly meticulous,researchers pay high attention to high-brightness leaser output.To obtain high brightness semiconductor lasers with fiber coupling output,take 6 single-emitter laser diodes with ? = 940 nm,cavity length3.5 mm,emitter size of 1 ?m × 30 ?m,fast axis divergence angle of 30o,slow axis divergence angle of 10o and laser power of 6 W,are assembled,based on equal optical path design.The optical system consist of laser alignment,laser beam combining and laser focusing.Designing optical system in ZEMAX,make simulation on high brightness semiconductor lasers with d = 50 ?m and NA = 0.12 multimode fiber output has been achieved according to fiber rule.The diameter of laser spot can be 38.5 ?m,the laser power of fiber output can be 35.5 W,the efficiency of laser coupling can be 98.6%,the laser brightness of fiber output can be 44.3 MW/(cm2·sr).Lastly,based on the defects of divergence angle,unequal optical path,step height,angle deviation and positional deviation,draw the conclusion through analysis of lasers far filed distribution,that coupling efficiency were decreased largely when the increasing of angle deviation or positional deviation.