Narrow Bandwidth Fiber Laser Based on Carbon Nanotubes and Saturable Dynamic Induced Grating

Narrow bandwidth mode-locked lasers serve as crucial light sources in many application domains such as spectroscopy and molecular excitation. In this Letter, we propose and experimentally demonstrate a novel narrow bandwidth mode-locked fiber laser by innovatively combining carbon nanotubes (CNTs) with saturable dynamic induced gratings (SDIGs) to achieve narrow bandwidth laser output. This mode-locked laser demonstrates outstanding performance, particularly in its capacity to achieve laser output with an extremely narrow spectral bandwidth of approximately 22.4 pm at half-maximum full width and a pulse sequence interval of 105.4 ns at a low pump threshold of 35 mW. Such characteristics endow this laser with significant advantages in a wide range of applications.