STABLE SINGLE-MODE COMPOUND-RING ERBIUM-DOPED FIBER LASER

In this paper we report the fabrication of a robust, tunable single-lo ngitudinal-mode compound-ring Er3+-doped Aber laser. The laser is fund amentally structured on an all-fiber compound-ring resonator in which a dual-coupler fiber ring is inserted into the main cavity. When combi ned in tandem with a mode-restricting intracavity tunable bandpass fil ter, the compound-ring resonator ensures single-longitudinal-mode lase r oscillation. The laser can provide up to 20 mW output power over muc h of its 1525 to 1570 nm wavelength tuning range, The short-term linew idth of the laser output measured is less than 5 kHz. The laser freque ncy is actively stabilized for a long time by exploiting the inherent filter nature of the compound-ring resonator. The reduction of an asso ciated frequency modulation is also discussed in detail.