Generation of blue light in Yb-doped double-clad fiber laser

Compact and efficient blue light source are attractive for numerous and technical applications such as laser-based metrology, data storage, medicine, xerography, and biotechnology. Nonlinear frequency conversion remains an attractive route to achieving blue light sources. In this paper we show that 915nm laser diode pumped Yb-doped double clad fiber lasers (YDCFL) can provide efficient 978nm light. Frequency doubling of the 978nm line of YDCFL can else generate blue (489nm) light. We setup theoretical model of Yb-doped. double clad blue fiber laser. The threshold and Output powers at 978nm and 489nm versus the fiber length, the core diameter, the size and numerical aperture (NA) of the inner cladding, and pumped power are studied through theoretical simulation. The optimum parameters are obtained. In the design of three-level double-clad fiber lasers, we consider two main considerations: high pump brightness and an optimum balance between spectral filtering and modal gain discrimination. A type I phase-matched BBO crystal, is used to generate second harmonic light(489nm).