Fabrication of OH-free multimode fiber by vapor phase axial deposition

An ultimately OH-free multimode optical fiber was fabricated by vapor phase axial deposition (VAD). Dehydration conditions were investigated using a newly designed electric furnace. To exclude the OH ion contamination during a fiber-drawing process, simultaneous deposition of core and cladding was carried out. The loss mechanism for the fabricated OH-free fiber was analyzed. Transmission loss for this fiber approached the theoretically estimated value. The low-loss window, with less than 0.5 dB/km attenuation, ranged from 1.2 to 1.7 μm. Realization of the OH-free VAD fiber promises a very useful application in wavelength division multiplexing optical transmission systems, and widens the choice of wavelengths for optical sources.