In this work, an experimental stability comparison between two different switchable Erbium- doped fiber lasers (EDFL) is carried out. Both topologies use fiber Bragg grating reflectors in order to select the emission wavelengths and two 2x4 optical switches. By adjusting the switches combinations, the lasers can be switched among the sixteen different wavelength lasing configurations. An output power instability analysis with time for both topologies was performed. The experimental results confirm that the topology based on a serial configuration offers a better stability and higher optical signal to noise ratios (OSNR) than the one based on a parallel configuration.