Fiber Bragg Grating Catheter Force Sensor

Real contact-force catheters used in cardiac ablation sense how hard the tip is pressed against tissue using three fiber Bragg gratings bonded 120° apart near the tip, with nothing electrical anywhere near the patient's heart. This simulator models the physics end to end: a beam-bending model turns your chosen contact force, contact angle and approach azimuth into per-fiber strain, the strain shifts each grating's reflected wavelength through the photoelastic and thermo-optic effects, and a closed-form decomposition — the same common-mode / differential-mode trick used for 3-phase power and RGB color mixing — reconstructs the force magnitude and direction purely from the three wavelength shifts. A temperature-drift slider and compensation toggle show why the axial (common-mode) channel needs a dedicated thermal reference while the bending (differential) channel cancels temperature automatically.