Polarization-maintaining and radiation resistant optical fiber with germanosilicate elliptical core

Abstract

This paper aims to consider fabrication of single-mode polarization-maintaining (PM) optical fibers with elliptical core, doped with 20 mol. % GeO2 and to study their optical properties and radiation resistance. The optical fiber preform was fabricated by chemical vapor deposition method. The low-oxygen central piece of the core in the preform was removed by high-temperature chemical gas-phase etching. The single-mode optical fibers 125 µm in diameter, with 65 µm thick polymer protection coating were drawn. The results of measurements of the optical properties at a wavelength of 1.3–1.55 μm confirmed that the highly-doped GeO2 optical fiber waveguides have a low optical loss and high radiation resistance owing to gas phase etching. Polarization-maintaining factor (h-parameter) of ≈ 8∙10-6 m−1 was achieved. As to the radiation resistance, our single-mode PM optical fiber with elliptical core appears to be quite competitive to the known PANDA PM optical fibers with a core made of pure silica glass.