All-Fiber Narrow-Bandwidth Mode-Locked Laser Based on Polarization-Dependent Helical Long-Period Grating
Ying Wan,
Chen Jiang,
Zuxing Zhang,
Yaya Mao,
Jianxin Ren,
Jianxiang Wen,
Yunqi Liu
Affiliations
Ying Wan
The Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, 219 Ningliu Road, Nanjing 210044, China
Chen Jiang
Advanced Photonic Technology Lab, College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China
Zuxing Zhang
Advanced Photonic Technology Lab, College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China
Yaya Mao
The Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, 219 Ningliu Road, Nanjing 210044, China
Jianxin Ren
The Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, 219 Ningliu Road, Nanjing 210044, China
Jianxiang Wen
Key Lab of Specialty Fiber Optics and Optical Access Networks, Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication, School of Communication and Information Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, China
Yunqi Liu
Key Lab of Specialty Fiber Optics and Optical Access Networks, Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication, School of Communication and Information Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, China
As a crucial component of nonlinear polarization rotation (NPR) mode locking, optical fiber gratings offer advantages such as polarization modulation capability, stability, fiber compatibility, and preparation maturity, making them a vital technological foundation for achieving NPR mode locking. Here, a polarization-maintaining fiber helical long-period grating (PMF-HLPG) was designed and fabricated as a polarizer using the CO2-laser direct-write technique to realize the NPR effect. A homemade fiber Bragg grating (FBG) was also introduced into the laser system to enable a narrow-bandwidth lasing output and wavelength tunability. Based on the PMF-HLPG and FBG mentioned above, an all-fiber mode-locked laser with a spectra bandwidth of 0.15 nm was constructed to generate stable short pulses with a fundamental repetition rate of 12.7122 MHz and a pulse duration of 30.08 ps. In particular, its signal-to-noise ratio is up to 84.5 dB, showing the high stability of the laser. Further, the operating wavelength of the laser can be tuned from 1559.65 nm to 1560.29 nm via heating the FBG while maintaining its mode-locked state with stability. The results indicate that the PMF-HLPG could be used as a polarizer to meet the NPR mechanism for ultrashort pulse laser applications in optical communication, optical sensing, and biomedical imaging.
