Passively Mode-Locked Fiber Ring Laser using Lu2O3 Thin Film Based Saturable Absorber

In this study, a stable and compact mode-locked erbium doped fiber ring laser (EDFRL) operating at 1560.78 nm is proposed based on lutetium oxide (Lu2O3) based saturable absorber (SA) thin film. By incorporating the Lu2O3 based SA film together with a 231.5 m long single-mode fiber (SMF) into an EDFL cavity, mode-locked laser pulses with a repetition rate of 0.7315 MHz and a pulse width of 735 ns were obtained at total forward and backward pumping power of 597.9 mW. The mean output power of the mode-locked pulses were measured as -6.46 dBm at 597.9 mW total pump power. It was observed that the mode-locked EDFRL output pulses have a signal-to-noise ratio (SNR) of 47.73 dB for the 0.7315 MHz fundamental frequency obtained with an RF spectrum analyzer. The performance of the developed mode-locked pulsed EDFRL shows that it can be used for nanosecond pulse generation applications in the 1550 nm region using a Lu2O3 based SA.