Tunable double-clad ytterbium-doped fiber laser based on a double-pass Mach–Zehnder interferometer

We have demonstrated an adjustable double-clad Yb3+-doped fiber laser using a double-pass Mach–Zehnder interferometer. The laser is adjustable over a range of 40 nm from 1064 nm to 1104 nm. By adjusting the state of the polarization controller, which is placed in the double-pass Mach–Zehnder interferometer, we obtained central lasing wavelengths that can be accurately tuned with controllable spacing between different tunable wavelengths. The laser has a side mode suppression ratio of 42 dB, the 3 dB spectral width is less than 0.2 nm, and the slope efficiencies at 1068 nm, 1082 nm and 1098 nm are 23%, 32% and 26%, respectively. In addition, we have experimentally observed tunable multi-wavelengths lasing output.

▶ Filtering characteristics of double-pass Mach–Zehnder interferometer were analyzed. ▶ Single-wavelength tunable range covered 40 nm from 1064 nm to 1104 nm. ▶ Tunable multi-wavelengths lasing output was also observed. ▶ Main factors limiting the output power were analyzed.