Using optimal cavity loss and saturable-absorber passive filter for stable and tunable dual-wavelength erbium fiber laser in single-longitudinal-mode operation

摘要

In this investigation, we propose and demonstrate experimentally tunable and stable dual-wavelength erbium doped fiber (EDF) double-ring laser scheme using different coupling losses inside cavity loop for wavelength and mode spacing tuning. Besides, a shorter unpumped EDF is also used to filter the side-modes for lasing wavelength in singlelongitudinal- mode (SLM) operation. However, the output mode spacing of dual-wavelength could be limited owing to the homogeneous broadening nature of EDF. As a result, the output performance of the proposed fiber laser have also been analyzed and discussed, such as wavelength tuning range, output power, side-mode suppression ratio (SMSR), stabilities of lasing wavelength and power, relative intensity noise (RIN), etc.