IFOG Based on Rhombic Optical Path Difference Bias Configuration for High-Frequency Angular Vibration Measurement

We propose a novel white light interferometric fiber-optic gyroscope (IFOG) based on rhombic optical path differential bias configuration to measure high-frequency angular vibration which meets the high demand in the aerospace industry. To raise the demodulation frequency, a high-performance semiconductor laser with fast wavelength switching capability and a three-wavelength quadrature demodulation technique are utilized to realize high-frequency angular vibration measurements with high accuracy. Experimental results indicate that linear output (
$\text{R}^{{2}} =0.999$
) can be achieved in detecting rotation rate with a scale factor of 0.076 rad/(°/s). Especially, 3 kHz sinusoidal vibration signals can be successfully demodulated by our proposed technique. This frequency is much higher than 100–300 Hz of the demodulation bandwidths that the IFOGs with other configurations have, provided the same 2000 m fiber coil is used. By increasing the wavelength tuning frequency of the laser and the detection frequency of the photodetector circuit, our method has the potential to measure high-frequency angular vibrations.