Coil Architecture
Winding methods for optical fiber coils that distribute the fiber from the inside out and the outside in across four symmetric layers reduce the sensitivity of the coil to thermal gradients. By employing a quadrupolar winding pattern, sensor manufacturers minimize the non-reciprocal phase shifts caused by time-varying temperature differences across the fiber. This specific geometry ensures that fiber segments equidistant from the coil’s midpoint are physically adjacent.
Symmetry Maintenance
Thermal asymmetry across the coil creates a false phase shift that mimics a rotation signal in interferometric gyroscopes. This layout ensures that a temperature wave propagating from the outside of the spool reaches both counter-propagating light beams at nearly the same time. The resulting phase shifts cancel each other out, preserving the bias stability of the sensor.
Inspection Protocol
Verification of the winding precision requires optical coherence domain reflectometry to locate any positioning errors or micro-bends in the fiber layers. A single misplaced turn can degrade the thermal performance of the entire coil assembly by a factor of ten. Thermal testing must be conducted to confirm the bias stability across the specified operating temperature range.
Assembly Constraint
Tension must be carefully controlled during winding to avoid induced stress that would lead to birefringence.
