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 Yb 3+ -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 Yb 3+ -doped PCF which contains an Yb 3+ -doped core of 23 μm in diameter and a holy inner clad of 420 μm 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 1111.770nm 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 nm, 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.