Long-period fiber grating as wavelength selective element in double-clad Yb-doped fiber-ring lasers

Abstract

Selection of operating wavelength of the Yb-doped fiber-ring lasers using long-period fiber gratings (LPFGs) is proposed. In the proposed method, customized LPFG that sustains high powers serves as a broad-band rejection filter. It modifies the net gain profile of the laser, enabling the peak gain to occur at a designed wavelength. Spectral range of oscillation between 1050-1110 nm was experimentally demonstrated. The spectral range can be extended to both shorter and longer wavelengths with proper design of the LPFG and length of the Yb-doped fiber. The gratings were inscribed by CO 2 laser and the grating period down to 175 μm was achieved being, to our best knowledge, the shortest reported LPFG period using this technique. Setup of the fiber laser

Self-induced laser line sweeping in an ytterbium fiber laser with non-resonant Fabry-Perot cavity

“…The SLLS effect was not to the best of our knowledge reported to the date (apart of a fluent mention made recently [23] on the existence of some temporal drift of a laser line in an YFL in similar experimental conditions).…”

“…also exhibit interest and are now under extensive inspection; see e.g. new results published in [22][23][24].…”

Thin-disk laser-pumping of ytterbium-doped fiber laser

“…In this experiment, the lasing wavelength can change over a wide range because of the broad spectral bandwidth of the cavity mirrors. Fiber Bragg gratings (FBG) as well as long-period fiber gratings (LPFG) could be integrated into the FL oscillator to realize narrow bandwidth operation with stable and selectable wavelength [31,32]. FBGs with adjustable center wavelength could be used to achieve a tunable output wavelength [8].…”

100 W ytterbium-doped monolithic fiber laser with fused angle-polished side-pumping configuration

“…With side-pumping, not only longer fiber can be used to ensure relatively uniform distribution of upper-level inversion particles, the thermal problem can be better managed as well. Furthermore, some ring fiber lasers [7,8] can employ side-pumping coupler. For high power fiber lasers, the unique side-pumping method is used which is mastered by SPI Corp. (UK) and IPG Photonics Corp.…”