A widely tunable, dual-wavelength fiber laser incorporating two polymer waveguide Bragg gratings

We present a continuously tunable dual-wavelength fiber laser based on polymer waveguide Bragg grating (PWBG) filters. The PWBG filters are used as wavelength selective components in the laser cavity. The 3 dB linewidth of the lasing wavelength is measured to be 0.02–0.04 nm over the whole wavelength tuning range. This range is 18.9 nm, from 1546.6 to 1527.7 nm. A linear response of the peak wavelength to the applied electrical power is achieved. The tuning efficiency of the single wavelength is −0.19 nm mW⁻¹. The wavelength spacing for the dual-wavelength fiber laser is tuned from 1.2 to 18.9 nm. The side-mode suppression ratio achieved is more than 35 dB over the whole tuning range. Stability of the dual-wavelength laser is accomplished by careful adjustment of the polarization states of the dual wavelengths. (letter)