Back reflection and pump instability effects on a fiber laser system

A tunable ring configured erbium doped fiber laser (EDFL) system was developed and its dependency on signal back-reflection and pump instability is presented. The signal back-reflection was simulated by launching another signal tuned at exactly (+0.01 nm accuracy) the same wavelength into the output port of the EDFL system. The power of the simulating source was increased up to 3 mW launched power, while the ring laser output was observed for the peak power, peak power fluctuation, signal side mode suppression ratio, linewidth and lasing threshold. Real time monitoring of the laser output, pump output and wavelength fluctuations were observed on an optical spectrum analyzer (OSA). The pump source was a laser diode with a center frequency at a wavelength of 978 nm.