Patent ID: 11947159
Assignee: HONEYWELL INTERNATIONAL INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An interferometric fibre optical gyroscope (IFOG), comprising:
a fibre coil wound around a winding axis and comprising a first fibre coil port and a second fibre coil port;
wherein the fibre coil comprises a hollow core optical fibre, wherein the hollow core optical fibre comprises (a) a tubular outer jacket comprising an inner surface, (b) a hollow core, and (c) a cladding, wherein the cladding comprises a plurality of glass cladding capillaries, wherein the hollow core is bounded by inwardly facing portions of outer surfaces of the plurality of glass cladding capillaries, wherein the plurality of glass cladding capillaries are arranged around the hollow core, and wherein each glass cladding capillary is bonded to the inner surface of the tubular outer jacket;
a laser system configured to generate a first optical signal; and
an optical coupler optically coupled to the laser system, the first fibre coil port and the second fibre coil port, configured to split the first optical signal into a clockwise optical signal, which is configured to propagate around the fibre coil in a clockwise direction around the winding axis, and a counterclockwise optical signal, which is configured to propagate around the fibre coil in a counterclockwise direction around the winding axis, and configured to receive a portion of the clockwise optical signal and a portion of the counterclockwise optical signal emitted from the fibre coil that have a differential phase proportional to rate of rotation of the fibre coil around the winding axis;
wherein each of the clockwise optical signal and the counterclockwise optical signal are linearly polarized in the hollow core optical fibre, and wherein the hollow core optical fibre has a holding parameter value of less than 1×10−5 m−1, or less than 1×10−6 m−1, or in a range of 1×10−6 m−1 to 1×10 −5 m−1, or in a range of 1×10−7 m−1 to 1×10−6 m−1or in a range of 1×10−7 m−1 to 1×10−5 m−1.