Wavelength control of a Tm-doped fiber laser using nonidentical mechanical long-period fiber gratings

Abstract

We present wavelength tuning operation of a Tm-doped silica fiber laser pumped by a laser diode emitting at 1.63 μm. Wavelength tuning is achieved by two nonidentical mechanical long-period fiber gratings (LPFGs) induced in a single-mode fiber using coil springs. The inter-resonance-mode passband, which is formed between the rejection bands due to the core-to-cladding mode coupling, dominates the gain peak in the fiber laser resonator. The oscillation wavelength is controlled between 1865 and 1972 nm by tuning the grating periods of the two LPFGs.