Katsumi Orimo

High-rate deposition VAD process using a double-flame burner

Flame temperature and stream have been studied using a Mach-Zehnder interferometer to improve the deposition rate in the VAD process without deterioration in the refractive-index profile of the Gl fiber.

Fluorine doping in the consolidation process of VAD soot preform for single-mode fibers

Advantages of depressed cladding single-mode fibers have been recognized for a couple of years, and many studies of these fibers by the MCVD method have been published. However, only a few studies have been reported on the VAD method.1,2 We now report a new simple technique for fabrication of depressed cladding single-mode fibers by the VAD method with low losses such as 0.40 dB/km at 1.30 μm and 0.28 dB/km at 1.55 μm.

Radiation effects on single-mode fibers

Fluorine doping in cladding, useful for minimizing the γ-ray-induced loss in multimode fibers with pure silica core, has been found to cause large γ-ray- induced loss in single-mode fibers. Radiation resistance of fluorine-doped silica seemed to be inferior to that of germanium-doped silica with the same refractive-index difference, |∆+| or |∆−|.