Triple-frequency operation of an Er-doped twincore fiber loop laser

Simultaneous laser operation of three single-frequency modes from an inhomogeneously broadened Er-doped twincore fiber loop laser is reported. Equal output power of 390 μW, separation 0.5 nm, and linewidth <10 kHz were measured for each mode in a travelling wave cavity comprising a single gain medium. In addition up to eight wavelength operation has been observed, demonstrating that twincore EDFA's can provide channel equalization in an eight-channel multiamplifier optical network.