1.5 μm fiber lasers have shown significant potential in space applications while space ionizing radiation significantly increases the loss of the active fiber. Therefore, it has become necessary to enhance the radiation resistance of the active fiber.

Recently, a research team from Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences (CAS) has proposed an optimized doping composition for radiation-resistant Er/Yb co-doped fibers, which demonstrates excellent performance in both laser properties and radiation resistance. The result, entitled “Effect of Ce co-doping on radiation resistance behavior and laser performance of Er/Yb/Ce co-doped high-phosphorous polarization-maintaining silica fiber”, was published in Ceramics International on January 6, 2025.

Currently, Ce co-doping is commonly used to enhance the radiation resistance of Er/Yb co-doped fibers for space applications. However, while high Ce concentrations can improve the radiation resistance of fiber, they also significantly degrade the fiber's laser performance. Therefore, determining the appropriate Ce concentration is essential to balance laser and radiation resistance performance.

The research team systematically studied the optical and radiation-resistant properties of Er/Yb/Al/P/Ce co-doped silica glass cores with varying Ce₂O₃ concentrations. Results showed that a small amount of Ce doping yielded better optical and radiation resistance properties. Although higher Ce concentrations offered slight improvements in radiation resistance, they led to a significant decline in optical performance. Based on these findings, Er/Yb/Ce co-doped fibers with different compositions were fabricated, and their experimental results aligned with those of the glass samples.

In terms of mechanism analysis, the team, by employing RIA and EPR spectroscopy, demonstrated that Ce co-doping could effectively suppress P-related defect formation. L₃-edge XANES further confirmed the dynamic valence state transformation of Ce ions during irradiation.

This study addresses the issue of relatively low laser efficiency in radiation-resistant Er/Yb co-doped fibers. It has developed an Er/Yb co-doped fiber that retains high laser performance without compromising radiation resistance and therefore provided a valuable reference for radiation-resistant fiber lasers in space applications.

Fig. (a) Fluorescence intensity changes of glass samples with different Ce concentrations before and after irradiation;(b) Variation in laser efficiency of different Er/Yb co-doped fibers with radiation dose; (c) L₃-edge XANES spectra of CeF₃ and CeO₂ samples, and (d) XANES spectra of glass samples before and after 100 krad X-ray irradiation.

Article website:

https://www.sciencedirect.com/science/article/pii/S0272884224052027

Contact: SHAO Chongyun

Advanced Laser and Optoelectronic Functional Materials Department,

Shanghai Institute of Optics and Fine Mechanics, CAS

Email: shaochongyun@siom.ac.cn