Broadband fiber laser with selective and stable narrow linewidth wavelength over 68 nm selectable bandwidth

In this paper, a stabilized and wavelength-selective erbium-doped fiber (EDF) laser architecture with single-longitudinal-mode, high optical signal to noise ratio (OSNR), stability, wide tunability and narrower linewidth is investigated experimentally. To suppress the dense longitudinal-mode fluctuations and reduce the output linewidth, the proposed four-fiber-ring with Rayleigh backscattering feedback injection and an EDF based saturable absorber is added in the ring cavity. So, the presented EDF laser configuration can provide a 68 nm wide wavelength-selective bandwidth of 1513.0–1581.0 nm by operating the original C-band gain-medium and also achieve a flattened power output with 0.3 dB power fluctuation in the bandwidth of 1529.0–1573.0 nm. Moreover, the related output characteristics of the proposed fiber laser are executed and discussed.