Two-wavelength fibre gyroscope with wide dynamic range

An optical fibre gyroscope configuration which utilises dual-wavelength determination of the Sagnac shift is described. It is shown that this provides a means of extending the unambiguous rotation sensing range, and thus the dynamic range, of the gyroscope. Using an all-fibre system and sources at wavelengths of 812 nm and 842 nm, an increase in unambiguous sensing range of approximately 27 times is demonstrated.