Cavity configuration study of an EDFL system

In this paper, experimental results are presented comparing the effects of co-propagation and counter-propagation configurations on the erbium-doped fiber laser (EDFL) output. Counter-propagating system refers to the configuration where pump light is traveling along the fiber in a direction opposite to that of the oscillation light, whereas co-propagating has the laser pump light in the same direction as the oscillation. This paper emphasizes on the configuration effects on the system's output power, amplified spontaneous emission (ASE), side mode suppression ratio (SMSR) and tuning range for a tunable system, at several different erbium doped fiber lengths. An observation was also made for both configurations in a fixed-wavelength fiber laser system.