A DESIGN METHOD FOR LOW DISPERSION POLARIZATION-MAINTAINING OPTICAL FIBERS WITH 2 HOLLOW PITS

A design method to realize the large modal birefringence and the low dispersion (within +/- 2 ps/km/nm) over the spectral range 1.30-1.55-mu-m is investigated for the polarization-maintaining optical fibers with the crescent or circular hollow pits. When the low dispersion is satisfied for the HE11(0) mode, one of two orthogonally polarized HE11 modes, it is found that (1) the cresent pits type has a larger modal birefringence than the circular pits type for DELTA-1 < 1.21% (DELTA-1: the relative index difference), and (2) the maximum modal birefringence of the crescent pits type is nearly equal to that of the circular pits type for DELTA-1 > 1.21%.