Jacques Warnier

The performance of depressed-cladding single-mode fibers with different b/a ratios

Depressed-cladding single-mode fibers with a first cladding-to-core ratio (b/a) ranging from seven to one and relative refractive-index differences of the core from 0.25 to 0.35% and of the cladding from 0 to -0.2% are investigated experimentally with respect to the LP/sub 11/ mode cutoff properties, the mode-field diameter, the dispersion, and the bending attenuation. Numerical calculations based on actual profile parameters of the bend loss and the mode-field diameter agree well with experiment. It is demonstrated that low attenuation and bend losses independent of b/a can be obtained if the cutoff wavelength is kept constant by adjusting the core radius, the core index or the index of the first cladding. >

PCVD at high deposition rates

Optical preforms and fibers (both single mode and multimode) were prepared by PCVD at deposition rates up to 3.0 g/min. Excellently smooth index profiles and optical losses as low as those previously reported at 0.5 g/min have been obtained.

Hybrid technology for large SM fiber performs

A hybrid technology for the preparation of standard and dispersion-modified single-mode (SM) fibers is discussed. Only the most important central region of the fibers is prepared by plasma chemical vapor deposition (PCVD) techniques. The optical cladding is as a high-purity jacket tube using the normal rod-in-tube obtained from low-cost shaping and sintering technologies. Due to in situ plasma etching, no disturbance is caused by the interfaces. Low attenuation is achieved with less than 5% of the fiber volume consisting of PCVD core region. The hybrid technology allows economic mass production of preforms containing more than 300 km of fiber. >