Broadly tunable Tm/Ho-codoped fiber lasers based on temperature-sensitive single-mode-multimode-single-mode fiber structures.

We present all-fiber tunable lasers using single-mode-multimode-single-mode (SMS) structures involving a liquid cladding in the multimode section. We make use of large thermooptic coefficients of the refractive-index liquids to tune the laser oscillation wavelength. The oscillation wavelength is changed over a range of 100 nm from 1858 nm to 1958 nm by controlling the temperature of the SMS structures in the Tm/Ho-codoped fiber ring resonators.

Tunable Tm/Ho-codoped fiber lasers based on an extensible liquid core between a pair of fused multimode-single-mode fibers.

We present mechanically tunable Tm/Ho-codoped fiber lasers based on multimode interference in single mode-multimode-single-mode structures. The intermediate multimode fiber (MMF) is separated into two segments with a liquid core in between. The mode field diameter of the single-mode fiber is designed to 13 µm for the MMF having a core diameter of 105 µm. The tunable range is attained to 64 nm by extending the effective length of the MMF. The laser wavelength is tuned over the ranges of 1809-1866 nm and 1866-1930 nm for the initial MMF lengths of 35.3 and 34.5 mm, respectively.