We report a study of an all-fiber Tm-doped fiber laser with tunable single wavelength emission and dual-wavelength generation operating in different laser wavelength ranges depending on the Tm-doped fiber (TDF) length. The wavelength selection and tuning for single wavelength laser operation and the adjustment of cavity losses for dual wavelength laser operation is obtained by temperature variations of the high birefringence fiber loop in a fiber optical loop mirror. Stable dual wavelength operation is achieved at the single wavelength tuning limits when cavity losses are balanced to generate two simultaneous laser lines with equal powers. A linear cavity fiber laser setup with TDF lengths of 2, 4, 8 and 12 m is used to obtain tunable single wavelength operation in a range of ~40 nm for each TDF length. A total tuning range of ~110 nm with the four different TDF lengths is achieved. At dual-wavelength laser operation the wavelength separation was ~48 nm. The maximal power efficiency of ~34.9% with a maximum output power of 274 mW was obtained with the use of TDF length of 4 m.

No abstract

Dual-wavelength laser emission of a ring cavity Tm-doped fiber laser with a separate wavelength selection of the simultaneously generated laser lines is experimentally demonstrated. A dual-wavelength laser operation is obtained by using two homemade multimode interference (MMI) filters with transmission peaks at the wavelengths of 1814.23 and 1872.15 nm, which are placed in a Mach Zehnder interferometer configuration for independent selection of the dual-wavelength generated laser lines. The selection of the shorter laser wavelength is achieved by submerging the MMI filter in different ethylene glycol/ water mixtures, reaching a wavelength selection in the broad range of ~24 nm. The stability results of the simultaneously generated laser lines are also shown. The use of the proposed MMI filters as reliable spectral filters for dual-wavelength generation in all-fiber Tm-doped fiber laser systems is experimentally demonstrated.

No abstract

No abstract