Effect of soaking temperature on concentrations of rare-earth ions in optical fiber core in solution doping process

Abstract

ABSTRACT Effect of soaking temperature on concentration of rare-earth ions in the optical fiber core during solution doping processwas investigated. The dopant concentration of Er 3+ and Ho 3+ in the preforms and the fibers measured by the electron probemicroanalysis (EPMA) and the optical spectrum analyzer (OSA) was found to increase with decreasing the soakingtemperature. The increase in the concentration of the Er 3+ and the Ho 3+ was attributed to the precipitation of the dopants dueto the decrease in the solubility by decreasing the temperature.Keywords: Erbium, Solution doping, Optical fiber, Soaking temperature, Solubility, Capillary force 1. INTRODUCTION Optical fibers doped with rare-earth ions have been extensively studied for the application of optical amplifiers and opticalfiber lasers. 1-2 Since dopant ions in the core of the fibers are active species, several doping processes are developed toincorporate the dopants in large concentration without formation of clusters. Solution doping method is one of the populardoping methods and it has been widely used in doping rare-earth ions into the optical glass fibers.