Improved SBS suppression in high power fibre lasers using metal coated active fibre

We present a simple, low cost, technique for the rapid heating and fine control of the longitudinal temperature profile of an active optical fibre with metal outer coating. The novel combination of resistive (Joule) heating and a selective coating etching procedure allow near arbitrary thermal profiles to be imparted along the length of the active fibre. The low thermal mass of the active fibre results in very rapid heat-up times. Using this technique, fibre temperatures in excess of 400°C can be reached in seconds and efficiently applied directly to the active fibre.