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• Chinese Optics Letters
• Vol. 20, Issue 9, 091601 (2022)
Yinggang Chen1、2, Zhiquan Lin3, Yafei Wang1, Meng Wang1, Lei Zhang1, Yan Jiao1、2, Hehe Dong1, Shikai Wang1、*, Chunlei Yu1、2、3、**, and Lili Hu1、2、3、***
Author Affiliations
• 1Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
• 2University of Chinese Academy of Sciences, Beijing 100039, China
• 3Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
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Yinggang Chen, Zhiquan Lin, Yafei Wang, Meng Wang, Lei Zhang, Yan Jiao, Hehe Dong, Shikai Wang, Chunlei Yu, Lili Hu. Nd3+-doped silica glass and fiber prepared by modified sol-gel method[J]. Chinese Optics Letters, 2022, 20(9): 091601 Copy Citation Text show less

Abstract

Large-size $Al3+/Nd3+$ co-doped silica glass with 5000 ppm $Nd3+$ and 50,000 ppm $Al3+$ doping concentrations was prepared by the modified sol-gel method combined with high-temperature melting and molding technology. Electron probe micro-analyzer tests indicated that high doping homogeneity was achieved with this sample preparation method. The spectral properties of the $Nd3+$ ions were evaluated. $Nd3+$-doped silica fiber (NDF) with a core-to-clad ratio of 20/125 μm was drawn from the preform with the $Al3+/Nd3+$ co-doped silica glass as the core. In the laser oscillation experiment, a maximum output power of 14.6 W at 1.06 μm with a slope efficiency of 39.6% was obtained from the NDF pumped by a commercial 808 nm laser diode. To the best of our knowledge, this is the highest laser power reported for an NDF operated at 1060 nm and prepared by a non-chemical vapor deposition method. In the master oscillator power amplifier experiment, a maximum power of 16.6 W corresponding to a slope efficiency of 30.5% at 1061 nm was also demonstrated. The laser performance of the NDF exhibited the great advantages and potential of the modified sol-gel method in fabricating $Nd3+$-doped silica glass for a new type of NDFs like large mode area fibers and fibers with large diameter ratio of core/cladding.

1. Introduction

$Nd3+$-doped silica fiber (NDF) has good thermo-mechanical properties of silica glass and a perfect energy level structure of $Nd3+$ ions, which is widely used in communication, biomedical, military, material processing, high-power laser, and other fields[1,2]. The $F43/2→I411/2$ transition of $Nd3+$ can generate a $∼1060 nm$ laser with extremely low laser threshold and long fluorescence lifetime, which benefits the laser output and energy storage. $Nd3+$-doped glass, crystal, and ceramics are well developed for this band[35]. Moreover, the application of $Nd3+$ in several other bands has also been widely considered by researchers. The $F43/2→I49/2$ transition of NDF can generate a $∼900 nm$ laser, which can be directly used in atmospheric detection, lidar, and $Yb3+$ ion pumping[6]. The deep blue lasers produced by its frequency doubling can be used in underwater communication, precision optics, atom cooling, and other fields[7,8]. The $F43/2→I413/2$ transition of NDF can generate lasers in the E-band of wavelengths (1350–1450 nm), which plays an important role in the fields of remote sensing, surgery, optical fiber communication, information storage, and so on[9,10]. These new applications require NDFs with a larger core-to-clad ratio and higher doping concentrations.

Copy Citation Text
Yinggang Chen, Zhiquan Lin, Yafei Wang, Meng Wang, Lei Zhang, Yan Jiao, Hehe Dong, Shikai Wang, Chunlei Yu, Lili Hu. Nd3+-doped silica glass and fiber prepared by modified sol-gel method[J]. Chinese Optics Letters, 2022, 20(9): 091601