Temperature distribution along DFB fibre lasers

We have investigated the effects of self heating of distributed feedback (DFB) fibre lasers on the performance of these lasers. Self heating, caused by non-radiative decay from the pump level to the upper laser level, increased the DFB laser temperature. The temperature decayed exponentially along the laser as the pump power was absorbed. The temperature profile depended on the absorption coefficient of the pump power and the lasing conditions. The non-uniform temperature profile chirped the grating which in turn detuned the laser cavity. The laser performance depended largely on the thermal properties of the material surrounding the laser. We believe that the temperature distribution levels out when the heat conductivity is increased along the laser, e.g. by placing the laser on an aluminium block