Fabry-Pérot (FP) fiber optic sensors are widely used for precise measurements of temperature, displacement, refractive index, and environmental parameters across scientific, industrial, and biomedical fields.

Temperature Sensing

FP fiber optic sensors are highly effective for temperature monitoring due to their compact size, high sensitivity, and immunity to electromagnetic interference. For example, a UV glue-filled FP cavity in a hollow capillary fiber can achieve a temperature sensitivity of 1.174 nm/°C in the 30–60 °C range, making it suitable for marine surveys, biological diagnostics, and environmental monitoring without interference from pressure variations . These sensors are also used in chemical and industrial processes where precise temperature control is critical.

Refractive Index Measurement

FP sensors can measure the refractive index (RI) of liquids and solids by monitoring interference fringe contrast caused by Fresnel reflections. This capability is valuable in biochemical sensing, chemical analysis, and material characterization, where detecting small changes in RI is essential for quality control and research .

Displacement and Structural Monitoring

FP interferometric sensors are employed for small displacement measurements and structural health monitoring. By tracking wavelength shifts in interference fringes, these sensors can detect minute movements or deformations in smart structures, aerospace components, and civil engineering applications . Their high precision and immunity to environmental noise make them ideal for monitoring critical infrastructure.

Industrial and Environmental Applications

FP fiber optic sensors are used in oil and gas exploration, seismic and sonar detection, and aerospace engineering. Their versatility allows for remote sensing in harsh environments, including high temperatures and pressures, where traditional electronic sensors may fail . Additionally, they are applied in oceanographic research for real-time water temperature monitoring and environmental studies .

Biomedical and Laboratory Applications

In biomedical research, FP sensors are used for biochemical assays and diagnostics, where precise measurement of temperature, RI, or displacement is required. Their compact design and high sensitivity allow integration into lab-on-a-chip devices and microfluidic systems for real-time monitoring of biological samples .

Summary

FP-type fiber optic sensors are versatile, precise, and robust, making them suitable for a wide range of applications:

• Temperature monitoring in industrial, marine, and biomedical environments
• Refractive index measurement for liquids, solids, and biochemical samples
• Displacement and structural health monitoring in aerospace and civil engineering
• Environmental sensing in harsh or remote conditions Their combination of high sensitivity, compactness, and immunity to electromagnetic interference ensures FP fiber optic sensors remain a key technology in modern sensing applications .