Broadened-Laser-Driven Polarization-Maintaining Hollow-Core Fiber Optic Gyroscope

A state-of-the-art fiber optic gyroscope (FOG) using a 250-m quadrupolar-wound coil of polarization-maintaining hollow-core fiber (HCF) interrogated by a broadened laser is demonstrated. The fiber coil is directly connected to the multi-function integrated optics chip (MIOC) to reduce instabilities and reflections. The HCF FOG is first driven with a broadband source, yielding an angular random walk (ARW) of 2.12 mu rad/root Hz and a drift of 0.375 mu rad. This drift is 3.4 times lower than reported in any previous HCF FOG. Measuring the loss and ARW versus wavelength of the HCF FOG driven by a tunable narrow-linewidth laser reveals that the HCF supports a dense spectrum of high-scattering surface modes (similar to 70 modes/nm). The HCF FOG was also interrogated with a 22.5-GHz broadened-laser source, yielding an ARW of 6 mu rad/root Hz. This ARW is most likely limited by backscattering mediated by coupling to the high-scattering surface modes. The drift of the HCF FOG driven by the broadened laser was 0.88 mu rad. This drift is limited by polarization coupling, and confirms the holding parameter given by the fiber provider for this fiber (10(-3) m(-1)).