Tunable Single-Longitudinal-Mode Thulium–Holmium Co-Doped Fiber Laser with an Ultra-Narrow Linewidth by Utilizing a Triple-Ring Passive Sub-Ring Resonator
Pengfei Wang,
Fengping Yan,
Qi Qin,
Dandan Yang,
Ting Feng,
Peng Liu,
Ting Li,
Chenhao Yu,
Xiangdong Wang,
Hao Guo,
Yuezhi Cai,
Wenjie Ji,
Youchao Jiang
Affiliations
Pengfei Wang
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
Fengping Yan
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
Qi Qin
School of Mechanical and Electrical Engineering, Xingtai University, Xingtai 054001, China
Dandan Yang
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
Ting Feng
Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University at Qinhuangdao, Qinhuangdao 066004, China
Peng Liu
School of Mechanical and Electrical Engineering, Xingtai University, Xingtai 054001, China
Ting Li
School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
Chenhao Yu
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
Xiangdong Wang
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
Hao Guo
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
Yuezhi Cai
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
Wenjie Ji
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
Youchao Jiang
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
A low-cost, wavelength-tunable single-longitudinal-mode (SLM) thulium–holmium co-doped fiber laser (THDFL) in a 2 μm band with a simple structure is described in the present paper. To obtain a stable SLM and narrow laser linewidth, a five-coupler-based three-ring (FCTR) filter is utilized in the ring cavity of the fiber laser. Tunable SLM wavelength output from THDFLs with kHz linewidths can be achieved by designing the FCTR filter with an effective free-spectral range and a 3 dB bandwidth at the main resonant peak. The measurement results show that the laser is in the SLM lasing state, with a highly stabilized optical spectrum, a linewidth of approximately 9.45 kHz, an optical signal-to-noise ratio as high as 73.6 dB, and a relative intensity noise of less than −142.66 dB/Hz. Furthermore, the wavelength can be tuned in the range of 2.6 nm. The proposed fiber laser has a wide range of applications, including coherence optical communication, optical fiber sensing, and dense wavelength-division-multiplexing.
