Selectable dual-wavelength erbium-doped fiber laser with stable single-longitudinal-mode utilizing eye-type compound-ring configuration

•Selectable dual-wavelength EDF laser with SLM output by employing eye-type compound-ring is proposed.•Employing the proposed compound-ring filter, the densely spaced longitudinal modes should be suppressed highly.•Mode-spacing of lasing dual-wavelength can be tuned from 1 to 30 nm.

In this paper, a tunable dual-wavelength erbium-doped fiber (EDF) ring laser with stable single-longitudinal-mode (SLM) under a tuning range of 1530.0–1560.0 nm is proposed and demonstrated. Here, the mode spacing of lasing dual-wavelength from 1.0 to 30.0 nm can be selected arbitrarily in any wavelength position. To accomplish the SLM output, the eye-type compound-ring scheme is proposed inside ring cavity for suppressing the multi-longitudinal-mode (MLM) highly. The entire measured output power and optical signal to noise ratio (OSNR) of each dual-wavelength are larger than −13.3 dBm and 60 dB respectively. In addition, the output stability measurement of proposed EDF laser is also performed and analyzed.