Optical narrowband filter and its application to fiber lasers

Single-mode fiber laser is a very important light sources for optical sensing and optical communication. The coupled mode function of basing on saturable absorber optical narrow-band filter using numerical analysis was soluted. The factors who effected optical narrow-band filter output response properties, for example the length of Erbium-doped-fiber, the absorption coefficient of Erbium-doped-fiber and the pump wave power was analysed. The length of Erbium-doped-fiber composing saturable absorber inversing with the response bandwidth of filter was verificated experimentally. The optical narrow-band filter to fiber laser was applied, then narrow-band single-longitudinal-mode laser output was got, and the linewidth of laser output is about hundreds of Hertz magnitude. The power of output laser is more than 1 mW and the lasing time of no mode-hopping is more than 2 hours. The power instability of the fiber laser is less than 0.0287%.