New theoretical model of ytterbium-doped double-clad fiber for laser application

We present a new analytical model which allows to model a double clad fiber amplifier or a laser. Comparison with experimental results using a sided pumping scheme with a double clad ytterbium -doped fibre laser is performed. We present a new analytical model which allows to model an amplifier or a laser using a DCF. The multimode pump is modeled by a equivalent source term launched in the single core of the DCF. It leads to an analytical model comparable to a single mode fiber model. We use it to calculate the evolution of the amplified spontaneous emission (ASE) along the fiber, and find out the optimum fiber length for laser operation.