Open AccessClosed-loop resonant fiber optic gyro with an improved digital serrodyne modulation
Author(s) -
Zhonghe Jin,
Xuhui Yu,
Huilian Ma
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.026578
Subject(s) - optics , sagnac effect , linearity , loop (graph theory) , phase modulation , resonator , physics , modulation (music) , open loop controller , frequency modulation , dynamic range , control theory (sociology) , optical fiber , materials science , closed loop , acoustics , phase noise , mathematics , computer science , telecommunications , radio frequency , control (management) , combinatorics , quantum mechanics , control engineering , artificial intelligence , engineering
To widen the linear dynamic range and improve the linearity, a closed-loop resonant fiber optic gyro (RFOG) is proposed and experimentally demonstrated. To overcome the effect of the imperfect serrodyne modulation, an improved frequency shifting module is designed and constructed on a LiNbO3 phase modulator. Its frequency resolution is improved to 0.01 Hz which is equivalent to a rotation rate of 0.04°/h for an RFOG with a 12-cm diameter fiber ring resonator. With the frequency shifter applied in the RFOG, a closed-loop detection is demonstrated, whose bias stability is around 2 °/h, close to that of the open-loop output. Moreover, good linearity and wide dynamic range are also experimentally demonstrated thanks to the closed-loop operation. The measured result shows that the open-loop linear detection range of ± 215°/s is improved to ± 1076°/s. It is improved by a factor of 5. The open-loop scale factor nonlinearity of 1.2% is decreased to 0.02% (200 ppm), which is improved by a factor of 60. These are the best results reported to date, to the best of our knowledge, for closed-loop RFOGs.