Short-Wavelength, in-Band-Pumped Single- Frequency DBR Tm<sup>3+</sup>-Doped Germanate Fiber Laser at 1.7 <i>μ</i>m
Cen Xu, Xianchao Guan, Changsheng Yang, Changhe Wang, Tianyi Tan, Wei Lin, Qilai Zhao, Yafei Wang, Chengzi Huang, Xiaodan Teng, Yuxin Sun, Kaijun Zhou, Zhouming Feng, Zhongmin Yang, Shanhui Xu
Abstract
Based on several centimeters long heavily Tm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> -doped germanate fibers (TGFs) and in-band-pumped technique, a short-wavelength distribute Bragg reflector (DBR) single-frequency fiber laser (SFFL) emitting at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.7~\mu \text{m}$ </tex-math></inline-formula> is investigated experimentally. A stable single-longitudinal-mode laser output with a signal-to-noise ratio of greater than 60 dB and an operation wavelength of 1727 nm is realized. The maximum output power of 12.4 mW and the slope efficiency of 4.81% for the absorbed pump power are obtained from a 1.8-cm-long TGF pumped by a 1610 nm fiber laser. The measured relative intensity-noise of the SFFL reaches to around −130 dB/Hz at frequencies of over 10 MHz and the laser linewidth is 8.6 kHz. To the best of our knowledge, this is the first demonstration of the DBR Tm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> -doped SFFL with an operation wavelength in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.7~\mu \text{m}$ </tex-math></inline-formula> region. It is suitable for optical coherence tomography, methane gas detection and optical medical technology.