Broadband dispersion-compensating fiber for high-bit-rate transmission network use

The optimum refractive-index profile and drawing temperature were investigated so as to maximize the figure of merit for multicladding broadband dispersion-compensating fibers. Based on the results of the investigation, the authors have fabricated a highly bend-resistant fiber with a 92.6-ps/(nm dB) figure of merit using the modified chemical-vapor deposition method for dispersion compensation in the 1.5-1.6-µm wavelength region. The manufactured dispersion compensator does not suffer bend loss at 1.55 µm for curvatures of radia of 6.3 and 3.3 cm, and it has a 1.1-dB/km bend loss at a curvature of radius of 1.6 cm. Codoping the germanium silicate core with fluorine diminishes the optical loss down to 0.70 dB/km at a 1.55-µm wavelength.