Passively Q-switched Erbium-doped fiber laser with brass-based saturable absorber

Abstract

The operating wavelength in the 1.5 µm region is made accessible through an Erbium-doped fiber as a gain medium. The minimum optical loss of this region has proven beneficial in the application of pulsed fiber lasers. However, the ideal material to act as passive modulator for the system is yet to be found. Therefore, this research proposed the generation of pulsed fiber laser using metal based passive saturable absorber by utilizing brass-based 3D printer filament. A free-standing film was fabricated using chitin as host polymer for ease of integration in the laser ring cavity. The Erbium-doped fiber laser with brass-chitin based polymer composite film generated Q-switched pulses within the input pump power of 135.7 mW to 172.3 mW. The repetition rate was increased from 55.80 kHz to 68.03 kHz. Meanwhile the pulse width was reduced from 3.06 µs to 2.24 µs, with corresponding maximum instantaneous pulse energy and peak power of 2.10 nJ and 882.71 µW, respectively. The signal-to-noise ratio was measured at 67 dB, indicating a highly stable pulse generation.