Efficient coupling from semiconductor lasers into single-mode fibers with tapered hemispherical ends

Abstract

An efficient coupling from semiconductor lasers in the 1.3-microm range into single-mode fibers with tapered hemispherical ends (TH fiber) is described. Coupling efficiency of more than 35% is attainable with TH fiber coupling. Optimum radius of the end hemisphere is ~20 microm and is obtained with good reproducibility by drawing the fiber in an arc discharge. It was found that changes in laser characteristics due to reflected light are far less for TH fiber coupling than for flat-end coupling. Stable coupling modules using TH fiber coupling were fabricated for system use.