Effect of residual stress relaxation in boron-doped double cladding fibers by CO 2 laser

In this paper, the effect of residual stress relaxation in double cladding fiber (DCF) was studied experimentally. The DCF consists of a depressed inner cladding which is doped with boron (B). We used a pulsed carbon dioxide (CO 2 ) laser to scan the DCF in order to relax the residual stress in the fiber. The result shows that the resonant wavelength of the DCF shifts towards shorter wavelengths with increasing the cycles of scan.