Thermal effects in Yb-doped double-clad high power fiber lasers

Temperature distribution in Yb-doped double-clad high power fiber lasers (DCFL) was analyzed by the thermal conductive equations, and pump way and pump absorption coefficients which may influence cavity temperature were discussed based on this analytic solution. Results indicate that the temperature variation in radius can be neglected compared to that in axial direction; local temperature will be very high if merely adopted traditional end pump, then symmetrical two-end pump should be used in practice; temperature characteristics improves by reducing pump absorption coefficient, whereas output power decreases together. In conclusion an approach under distributed pump and with nonuniform pump absorption coefficients is proposed to get the best match of temperature distribution and output p