Switchable generation of multi-wavelength continuous wave and square-wave pluses in a bidirectional Erbium-doped fiber laser

Abstract We present a switchable generation of multi-wavelength continuous wave (CW) and square-wave pluses (SWPs) in a bidirectional erbium-doped fiber laser. The variable attenuator (VA) is used to realize switchable generation of CW and mode-locking pulse. In the multi-wavelength loop (MWL), the laser using the Sagnac loop output single-wavelength, dual-wavelength and triple-wavelength CW by finely adjusting the polarization controllers (PC). In the mode-locked loop (MML), the stable SWPs and harmonic mode-lock (HML) SWPs can be obtained by nonlinear polarization rotation (NPR) technique.