title: Pump efficiency improvement of a C-band tunable fiber laser using optical circulator and tunable fiber gratings.
abstract: We propose and demonstrate a tunable fiber laser based on an optical circulator (OC) and two tunable fiber Bragg gratings (TFBGs). The OC acts as a pump power router to improve the pumping efficiency, and a 4% increase in overall conversion efficiency has been observed. The combined tuning spectra range of two TFBGs could cover the entire C-band spectrum from 1530 to 1560 nm. Stable laser output power above 10 dBm is obtained using 1.9 m of erbium-doped fiber and TFBGs with 50% reflectivity. With power equalization by using variable optical attenuators, the power variation is less than 0.1 dB in the whole C band with narrow linewidth of 0.05 nm. A signal-to-noise ratio of 60 dB and a continuous tuning resolution of 0.5 nm have been achieved. The TFBG-based tunable fiber laser can be a promising light source for WDM transmission and fiber sensor applications.
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
authors.forename: S-K
authors.initials: SK
authors.lastname: Liaw
authors.forename: W Y
authors.initials: WY
authors.lastname: Jang
authors.forename: C-J
authors.initials: CJ
authors.lastname: Wang
authors.forename: K L
authors.initials: KL
authors.lastname: Hung