Co-lasing in an electrically tunable erbium-doped fiber laser

We demonstrate simultaneous wavelength operation (co-lasing) of an erbium-doped fiber ring laser with independent tunability of each wavelength over 35 nm between 1528 and 1563 nm. We study two different configurations and also investigate use of aluminum versus germanium codoped gain modules in the ring. We find that the aluminum codoped gain module has superior tunability.