Tunable erbium doped fiber laser based on a spherical micro-ball lens as a Fabry–Perot interference filter

Abstract The tunable wavelength emission of an erbium doped fiber laser using a Fabry–Perot interference filter based on a fiber micro-ball lens (MBL) with a spherical shape is experimentally demonstrated. The filter is formed at the tip of a single-mode fiber by controlled electric arc discharge. The filter consists of a fiber MBL with a radius of 152.7 µ m and a flat-convex mirror. A tunable single laser emission range of 1556.85–1569.72 nm is obtained when the mirror moves perpendicular to the fiber. Dual-wavelength laser emission with a separation of ∼12.9 nm corresponding to the free spectral range of interference modulation is obtained within the single laser wavelength tuning limits. The laser line exhibits full width at maximum half of 0.1 nm. The stability of the laser emission is also discussed. The use of a reliable tunable spectral filter for dual-wavelength emission and single tuning is demonstrated in the fiber laser’s design. The proposed spectral filter configuration can be useful in different research areas, such as the coherent development of light sources, optical communications, and optical instrumentation.