Monomode triangular index fiber excitation through upside down tapered cylindrical microlens on its end face: study of coupling in the presence of mechanical offsets

The analytical evaluation of the coupling optics, taking care of lateral and angular offsets, has been presented for an upside-down tapered cylindrical microlensed (UDTCM) single-mode circular core triangular index fiber (TIF) excited by laser diode (LD). ABCD matrix appropriate for this system in the transverse plane is being used in order to derive analytical formulae of coupling efficiencies (CE) in presence of the said kinds of mechanical offsets. Distribution of fields of both the LD and TIF are taken to be Gaussian type. This study employs two wavelengths 1.3 µm and 1.5 µm and three TIFs of different V numbers. Using the prescribed formulae, the concerned prediction involves little computation. This paper highlights the tolerance of the coupler with respect to the said types of mechanical offsets. The outcomes concerned with UDTCM will be helpful for optical packages.