A broadband fiber ring laser technique with stable and tunable signal-frequency operation

A C- plus L-band fiber ring laser with wide wavelength tunability and single-longitudinal-mode oscillation is proposed and demonstrated experimentally. A saturable-absorber-based autotracking filter, consisted of an unpumped erbium-doped fiber (EDF) and an optical reflected mirror (ORM), is employed to provide fine mode restriction and guarantee the single-frequency operation. Output power of > 2.1 dBm, power stability of 31 dB / 0.05 nm have been experimentally demonstrated for this single-frequency fiber laser over an operating range of 1550 to 1608 nm.