Both devices exploit the Sagnac effect to detect rotation, but the patent claims diverge along different engineering paths. Fiber optic gyroscope (FOG) claims cluster around coil winding methods, polarization-maintaining fiber and closed-loop detection electronics used to read out the phase shift in a fiber coil. Ring laser gyroscope (RLG) claims instead center on cavity design and lock-in dither mechanisms needed to overcome the frequency lock-in problem in a ring laser cavity. In this dataset both architectures are captured together, and IPC composition shows heavy overlap with optical-component classes (G02B, H01S) rather than gyroscope claims standing alone.

The ranking is dominated by a small group of long-established inertial-navigation suppliers, with the leading assignee holding 198 records against a fifth-place count of 37 and a tenth-place count of 12. The top 5 assignees combined account for 57.8% of all 952 records in scope, and the top 10 account for 65.4%. This is a genuinely concentrated field rather than one with many similarly sized competitors, so any new entrant’s claims will sit close to art already held by a handful of firms.

Complete-year data shows a decline from a peak of 33 filings in 2021 to 15 in 2024, a -55% change over that span. Figures for 2025 and 2026 in this dataset are still incomplete because patent publication typically lags actual filing by roughly 18 months, so those years will rise as more records publish. Treat the 2021-2024 trend as the reliable read and avoid drawing conclusions from the most recent one to two years.