THEORETICAL ANALYSIS OF A FOUR-LEVEL SINGLE-MODE FIBER LASER.

The relation between the output power and input pump power and then the threshold pump power and slope efficiency of a four-level single mode fiber laser is analysed in terms of the four-level rate equations and the numerical results are in good agreement with the available experimental results by M. Shimizu (1987). Meanwhile, the theoretical model of this paper is simpler and more reasonable than that of Shimizu and is applied to design a single mode fiber laser as well as a single mode fiber amplifier with four-level material. [ABSTRACT FROM AUTHOR]