Impact of highly nonlinear fiber and polarization controller on the spectral and power characteristics of ring type CW mode erbium-doped fiber lasers

Abstract This study investigates the performance characteristics of CW mode erbium-doped fiber (EDF) laser setups, emphasizing the impact of specific configurations of EDF, highly nonlinear fiber (HNLF), and a dispersion compensating fiber (DCF), as well as the roles of pumping lasers and polarization controllers (PC) within the laser cavity. The choice between I6 and Er-30 EDF types significantly influences parameters such as optical signal-to-noise ratio (OSNR) and operating wavelength range, with I6 EDF generally offering superior OSNR and a broader wavelength range. Integration of HNLF and DCF enhances spectral characteristics and stability, albeit without a substantial effect on output power. Utilizing a PC as a tuning element generally boosts output power compared to a fixed cavity design, which is particularly noticeable in setups employing the I6 EDF type. Regarding multiwavelength emission capabilities, dual-wavelength emissions were achievable with the Er-30 EDF setup, demonstrating spectral versatility at the expense of reduced OSNR compared to single-wavelength operation.