Tuning of an erbium-doped fiber ring laser based on heating a tapered fiber filter

•An erbium-doped fiber ring laser (EDFRL) with wavelength tuning is reported.•The laser has a Mach–Zehnder fiber interferometer (MZFI) based on tapers as an intracavity filter.•The MZFI is immersed in a glycerol solution, which refractive index is modified by controlled temperature changes.•Wavelength tuning of 12 nm was obtained.

An erbium-doped fiber ring laser (EDFRL) with wavelength tuning is reported. The laser has a Mach–Zehnder fiber interferometer (MZFI) based on tapers as an intracavity filter, which spectral interference transmission spectrum is modified by external refractive index changes induced by temperature variations in the 25–110 °C range. The MZFI is immersed in a glycerol solution, which refractive index is modified by controlled temperature changes, which allows the tuning of the laser wavelength determined by the interference fringes. Wavelength tuning of 12 nm was measured. This approach is very simple, portable and inexpensive over traditional methods to tune a fiber laser. In addition, the tuning mechanism do not require a solution replacement to operate.