%0 Journal Article %T Dynamic Free-Spectral-Range Measurement for Fiber Resonator Based on Digital-Heterodyne Optical Phase-Locked Loop %A Hongchen Jiao %A Tao Wang %A Heli Gao %A Lishuang Feng %A Honghao Ma %J Optics and Photonics Journal %P 332-340 %@ 2160-889X %D 2021 %I Scientific Research Publishing %R 10.4236/opj.2021.118023 %X
We propose a novel scheme, based on digital-heterodyne optical phase-locked loop with whole-fiber circuit, to dynamically measure the free-spectral-range of a fiber resonator. The optical phase-locked loop is established with a differential frequency-modulation module consists of a pair of acousto-optic modulators. The resonance-tracking loop is derived with the Pound-Drever-Hall technique for locking the heterodyne frequency of the OPLL on the frequency difference between adjacent resonance modes. A stable locking accuracy of about 7 กม 10?9 and a dynamic locking accuracy of about 5 กม 10?8 are achieved with the FSR of 8.155 MHz, indicating a bias stability of the resonator fiber optic gyro of about 0.1?/h with 10 Hz bandwidth. In addition, the thermal drift coefficient of the FSR is measured as 0.1 Hz/?C. This shows remarkable potential for realizing advanced optical measurement systems, such as the resonant fiber optic gyro, and so on.
%K Free Spectral Range %K Fiber Resonator %K Dynamic Measurement %K Digital-Heterodyne Optical Phase-Locked Loop %K Resonant Fiber Optic Gyro %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=111030