Optical gain of single mode short Er/Yb doped fiber

Optical gain and output power as a function of pump power has been calculated for short Er/Yb doped single mode fibers for various fiber parameters. The calculation shows that long fiber lengths provide both higher small signal gain and higher output power. Gain of 14 dB has been observed in a 30 mm long fiber at 400 mW of input pump power. The observed small signal gain is found to be linearly proportional to the length of the fiber with a slope of 0.44 dB/mm at 400 mW of pump power.