Feedback effects in erbium-doped fiber amplifier/source for open-loop fiber-optic gyroscope

We have investigated rotation-dependent feedback effects in an erbium-doped fiber source for an open-loop fiberoptic gyroscope with fiber amplifier/source configuration. Average power and optical spectrum of the source output as well as of the amplified signal output were found to vary depending on the rotation rate, resulting in the distortion of the gyroscope output. The distorted gyroscope output could be quantitatively explained by a theoretical model with the assumption that the source power and the gain variation due to feedback depends primarily on the average feedback signal power. It was found that the distortion in gyroscope output due to rotation-dependent feedback can be minimized when the phase difference is modulated with an amplitude of 2.405 rad where the average feedback signal power becomes independent of the rotation rate.