Temporal Characteristics of a High Power Erbium-Doped Fiber Ring Laser

The temporal characteristics of a fiber ring laser are reported. The laser has a simple configuration, which contains an Erbium-doped fiber amplifier (EDFA), a polarization controller (PC) and a coupler. The EDFA has a high saturation power of 27dBm to provide the gain in the cavity. The PC is used to control the polarization state of light. A 99/1 coupler is used to extract the laser output. There is no filter in the cavity to confine the spectrum of the laser. The simple laser configuration can operate in different temporal modes with different pump power. In the self mode locking state, the repetition rate is equal to the inverse of the round trip time of the cavity. The repetition rate of the laser can be increased by increasing the pump power of the EDFA. This self mode locking phenomena is due to the homogeneous gain medium in the cavity, rather than the nonlinear effect in the cavity. The nonlinear effect can suppress the self mode locking phenomena by inserting a short length highly nonlinear fiber in the laser cavity.