MISALIGNMENT CONSIDERATIONS IN LASER-DIODE TO SINGLE-MODE FIBER EXCITATION VIA HYPERBOLIC LENS ON THE FIBER TIP

We report what to our knowledge is the first theoretical investigation of the coupling efficiency of a laser diode to a single-mode fibre vi a a hyperbolic lens on the tip of the fibre in the presence of possibl e transverse offset and angular mismatch. By employing a recently form ulated ABCD matrix for refraction of paraxial rays by a hyperbolic int erface, we present analytical expressions of such coupling efficiencie s and evaluate the corresponding losses involving very little computat ions or even a pocket calculator. The results will be useful for the d esign of optimum launch optics to obtain maximum coupling efficiency. (C) 1998 Elsevier Science B.V.