We report on a tunable ytterbium-doped fiber laser bridging the gap from three-level lasing around 980 nm to true four-level lasing at 1066 nm. Wavelength-locking and -tuning was achieved by an external volume-Bragg grating (VBG). Results are compared with a numerical analysis based on a spectrally resolved rate equation analysis.

In this presentation the latest results on volume Bragg grating locked fiber lasers will be reviewed. This novel technique provides one to two orders of magnitude improved spectral brightness, improved temporal stability and at least equally efficient lasing as when ordinary dielectric mirrors are used. Results on tuning and photodarkening resistant fiber lasers are also presented, as well as some results where the lasers are used in nonlinear optics.

In this presentation the latest results on volume Bragg grating locked fiber lasers will be reviewed. This novel technique provides one to two orders of magnitude improved spectral brightness, improved temporal stability and at least equally efficient lasing as when ordinary dielectric mirrors are used. Results on tuning and photodarkening resistant fiber lasers are also presented, as well as some results where the lasers are used in nonlinear optics.

In this work we measure how photodarkening affects the optical efficiency for three different Yb/Al-doped silica fibers operating at 980 nm, one of which is codoped with cerium. A volume Bragg grating is used for linewidth control and added rejection of amplified spontaneous emission. Several hours of degradation-resistant operation is obtained with the Ce-codoped fiber, while for the Yb/Al doped fibers a large drop in efficiency is observed within the first hour of operation. Our results show that Yb/Ce/Al-doped fibers could be excellent candidates for high-power 980 nm fiber laser sources.

Two equal highly reflective volume Bragg gratings (VBGs) were used to lock an Yb-doped fiber laser. By heating one of the VBGs, its center wavelength was shifted and the laser was locked on the overlap between the main peak of one grating and the side-lobe of the other creating a large outcoupling with high spectral selectivity. With this simple arrangement, unidirectional output is achieved with a narrow linewidth (2.5GHz), high efficiency (>70%) and with an output power above 7W.

A linearly polarized fiber laser emitting at 979 nm with an output power of 2 W is presented. By using a photodarkening-resistant Yb/Ce/Al-codoped silica fiber, degradation-free operation is achieved over several hours.

A linearly polarized fiber laser emitting at 979 nm with an output power of 2 W is presented. By using a photodarkening-resistant Yb/Ce/Al-codoped silica fiber, degradation-free operation is achieved over several hours.