“…Minimum optical losses of about 10 dB/km at 1064 nm have been measured when such fibers were spliced to single-mode fibers at both fiber ends [25]. Several structures of Bragg fibers with claddings of three pairs of Bragg layers, a silica core or air cores of different diameters and two types of Bragg claddings have been designed and fabricated [27][28][29][30]. Using continuous-wave and pulsed laser sources operating at 975 [30], 1064 [27][28][29], or 1550 nm [29,30] optical losses, transmittances, bend losses of the fibers have been determined.…”