Excess noise in fiber gyroscope sources

Excess noise was measured in three potential interferometric fiber gyroscope sources, superluminescent diodes at 0.83 and 1.3 mu m, and a superfluorescent fiber source at 1.06 mu m. All three sources showed limiting signal-to-noise ratios in the 128-132 dB range (1 Hz bandwidth at 100 kHz), in agreement with their measured linewidths. The impact of the excess noise on the fiber gyro random walk coefficient is shown. It is pointed out that the noise source considered is important for interferometric fiber optic gyros because it imposes a limitation that does not arise in optical gyros which use narrowband sources.<<ETX>>