Numerical analysis of Yb/sup 3+/-sensitised, Er/sup 3+/-doped, fibre-ring laser

The performance of a Yb/sup 3+/-sensitised Er/sup 3+/-doped, continuous-wave, fibre-ring laser is analysed using a comprehensive numerical model. The model is based on iterative solution propagation-rate equations and takes account realistic refractive-index profile and Er/sup 3+//Yb/sup 3+/-doping distribution function, uniform upconversion from the /sup 4/I/sub 13/2/ erbium level and propagation of amplified spontaneous emission in the pump wavelength range. The dependence of output power on active fibre length, input pump power and output coupling ratio has been investigated. The analysis has shown that the laser can be tuned in the range 1525 nm - 1610 nm. The calculated ring-laser characteristics have been found in quantitative agreement with the experimentally obtained data.