Theoretical and experimental study of artificially controlled backscattering fiber using femtosecond laser fabrication

An artificially controlled backscattering (ACBS) fiber is theoretically proposed and experimentally verified using a femtosecond (fs) laser micromachining system. The backscattering power of the ACBS fiber per unit length is similarly defined as the one of the single mode fiber (SMF). We have calculated the relative reflecting power per unit length from a fiber with a reflector fabricated on an SMF core at 5576 m by the fs laser beam. The impact of the pulse energy of the fs laser and the reflector position on the performance of the ACBS fiber are then compared via observing the backscattering trace. The results show that the proposed ACBS fiber can enhance the backscattering of the SMF. High backscattering fibers (HBSFs) can be achieved via appropriate selection of fabrication parameters, offering an efficient way to shorten the fiber length and form a random distributed feedback fiber laser.