The theory of homogeneously broadened four level fiber lasers, which use fiber loops as distributed reflective elements, is examined. Such cavities can be made entirely from rare earth doped fiber. The amplifying characteristics of doped fiber loops are examined. The threshold pump power and the loop reflectivity necessary to optimize the lasing output power from an oscillator formed from two loops in series are predicted.
© 1989 Optical Society of America
Paul Urquhart, "Fiber lasers with loop reflectors," Appl. Opt. 28, 3759-3767 (1989)