Influence of air filling factor on photonic crystal fiber laser

Based on the principle of traditional fiber laser, rate equations and the power transmission equations of the single mode photonic crystal fiber(PCF) laser are given considering the mode field distribution of PCF, and then the characteristics of the ytterbium-doped single mode PCF laser are numerically analyzed. The results show that the air filling factor of PCF does not remarkably affect the output power, pump threshold power and slope efficiency, but markedly influence the non-linear Raman threshold of PCF laser. The PCF laser outputs signal light mainly or signal and Stokes lights simultaneously while the pump power is below or above the Raman threshold, respectively. Therefore, a concept of dual-wavelength fiber laser through controlling the pump power is presented. At the same time, the dual-wavelength laser oscillation with a relatively wide range of output power could be realized by employing the PCF with different structures.