Optimum position of isolators within erbium-doped fibers

An isolator is used as an amplified spontaneous emission suppressing component within an erbium-doped fiber. The optimum isolator placement is both experimentally and theoretically determined and found to be slightly dependent upon pump power. Improvements of 4 dB in gain and 2 dB in noise figure are measured for the optimum isolator location at 25% of the fiber length when the fiber is pumped with 60 mW of pump power at 1.48 mu m.<
>