Expanding The Dynamic Range Of An Open Loop Ifog

We propose and implement a new modulation and demodulation scheme which allows an open loop Interferometric Fiber Optic Gyroscope (IFOG) to expand its dynamic range, extending the maximum Sagnac phase measurement from the typical pi/6 rad to values limited only by the increase of signal to noise ratio when interference approaches the coherence length of the light source. Here we achieve a Sagnac phase measumerent of 116.8 rad keeping the measurement error below 0.1 rad for the whole range. Theoretically, there is no reason the error could not go as low as the typical error of a closed loop IFOG.