Multi-Wavelength Passively Q-Switched Fiber Laser Based on Erbium-Doped Fiber Saturable Absorber and Analysis of Gain Saturable Absorption Characteristics

In this paper, we report a multi-wavelength passively Q-switched fiber laser based on reconfigurable Lyot ring filter (RLRF) and Erbium-doped fiber (EDF) saturable absorber (SA). The gain saturable absorption characteristics of the EDF are analyzed in the experiments. When EDF is used as SA, EDF exhibits different nonlinear characteristics at different pump powers. Through the observation of the experimental data, we discuss the relationship between the multi-wavelength and passively Qswitching, in view of the position of the wavelength excitations and the presence or absence of the corresponding pulse sequence. The RLRF in the structure uses a 2 m long polarization maintaining fiber (PMF), and the wavelength interval between 1.5 and 3.0 nm can be effectively switched by adjusting the polarization controller (PC). The laser elaborated can flexibly switch from a single to seven wavelengths, with a corresponding pulse repetition rates of 24.11 – 59.38 kHz, a minimum Qswitched pulse width of 1.16 μs, a maximum average output power of 46.98 μW, and a maximum single pulse energy of 9.64 nJ.