Stable and wavelength- selectable C + L band fiber ring laser with single-longitudinal-mode by utilizing C-band erbium fiber amplifier.

In the investigation, we propose and demonstrate a wavelength-selectable C- plus L-band erbium-doped fiber (EDF) ring laser with single-longitudinal-mode (SLM) output. Here, a C-band erbium-doped fiber amplifier (EDFA) is utilized to serve as gain medium together with proposed multi-cross-ring (MCR) scheme to extend the wavelength tunability to L-band range. Besides, the MCR can also suppress the multi-longitudinal-mode (MLM) significantly. Therefore, the measured output power and optical signal to noise ratio (OSNR) of each lasing wavelength are between -10.1 and -2.7 dBm, and 26.4 and 35.0 dB/0.06 nm, respectively in the wavelength range from 1530.0 to 1584.0 nm. In addition, the output stabilities of power and wavelength in the proposed EDF MCR laser have been also analyzed experimentally.