Influence of misalignment of matching elements on the efficiency of coupling of radiation from a semiconductor injection laser into optical fibers

A theoretical analysis is made of the influence of the misalignment between the axes of a semiconductor laser beam and of multimode or single-mode fibers on the efficiency of coupling of radiation into the fibers. Two cases are considered: a direct contact between a laser and a fiber, and an indirect contact with a matching element in the form of a fiber segment with a square-law variation of the refractive index.