Purification of Er3+-doped fluorotellurite glass with low hydroxyl content

Abstract

Fluorotellurite glass is regarded as an ideal host material for infrared fiber lasers due to its relatively low phonon energy and high rare-earth doping capacity. However, its emission efficiency is limited by strong absorption of hydroxyl impurities (OH⁻) in the glass, which typically originate from the raw materials and their surrounding environment. In this study, we thoroughly investigated the impact of raw materials and corundum crucible under various conditions. A series of Er³⁺-doped fluorotellurite glasses was prepared using a high-temperature and low-pressure pre-drying technique, achieving a minimum OH⁻ absorption coefficient of 0.009 cm⁻¹, representing a 99.7 % reduction compared to the undried sample. Moreover, the integral area of peaks at 1550 nm and 2710 nm of the well-dried sample increased by 947 % and 1023 %, respectively, compared to the undried sample. These results demonstrate that fluorotellurite glass with low OH⁻ content holds promising potential for development in infrared fiber lasers.