Wavelength tunable Yb3+-doped double-clad photonic crystal fiber laser

Wavelength tunable high power lasers are desired for many applications, such as spectroscopy, sensing and nonlinear optics, etc. A tunable Yb3+-doped photonic crystal fiber laser based on a blazed grating in Littrow configuration is demonstrated. The active fiber used in the experiment is a double-clad Yb3+-doped PCF which contains an Yb3+-doped core of 23 mu m in diameter and a holy inner clad of 420 M in diameter. The laser resonator is composed of a dichroic reflective mirror and a blazed grating which is set in Littrow configuration. To reduce reflection the fiber end near to the grating is polished into an angle of 8 degree. Wavelength tunable output with a range form 1035.425 nm to 11 11.770nm is realized. The output power of the laser at different wavelengths is flatten within 0.8 dB. At the available maximum pump power of 12.11 W, the maximum output power of 3.45 W is obtained at 1064.085 rim, which corresponds to a slope efficiency of 35.9%. Degree of polarization of the output at different pump level are all more than 0.87.