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

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 lowpressure 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.