Optical Phase Displacement
Signal phase displacement metrics recorded across interferometric sensor channels establish the relative optical path length difference between interfering light waves. Phase shift delay quantifies the temporal or spatial phase shift experienced by light propagating through an optical fiber subjected to physical strain or temperature change.
Signal Demodulation
Interferometric demodulation electronics process phase modulation signals by comparing optical output against stable reference signals. Applied strain lengthens the fiber and modifies its refractive index through photoelastic effects, generating a proportional phase shift delay. Heterodyne or homodyne phase detection algorithms extract fractional optical fringe shifts with sub-nanometer resolution.
Signal processing field-programmable gate arrays continuously track phase changes across dynamic operational bandwidths.
Environmental Sensitivity
Unintended thermal gradients across optical fiber sensor arms induce unwanted phase shifts that contaminate strain measurements. Thermo-optic refractive index changes dominate thermal phase sensitivity, exceeding pure geometric elongation contributions by an order of magnitude.
Calibration Specification
Interferometer calibration protocols verify phase measurement accuracy using reference piezoelectric transducers calibrated against atomic frequency standards. Factory testing determines the scale factor relating physical displacement to phase shift delay in radians per microstrain. Procurement specifications mandate scale factor linearity within zero point zero one percent across the certified dynamic range.
Instrument certificates detail phase noise floor boundaries under reference environmental conditions.
