Simultaneous oscillation of wavelength-tunable, singlemode lasers using an Er-doped fibre amplifier

A compound fibre-ring cavity with just one Er-doped fibre amplifier yields wavelength-multiplexed laser lights, each of which is wavelength-tunable and singlemoded with a spectral linewidth <1 MHz. The allowable cavity-loss fluctuation for maintaining simultaneous lasing is ∼1 dB