How Fiber Sensors Work

Fiber sensors detect external parameters using the physical properties of optical fiber. They consist of a light source, optical fiber, modulators, demodulators, and photodetectors. The light from the source travels through the fiber and interacts with the measured parameter (such as temperature, pressure, or displacement), changing optical properties like intensity, wavelength, frequency, phase, or polarization. The modulated light is sent to a demodulator, converted into an electrical signal, and processed to obtain the measured value.

Depending on modulation, fiber sensors can be intensity-based, interferometric, wavelength-based, or polarization-based.

Intensity sensors measure changes in signal power and are simple but more susceptible to environmental interference.

Interferometric sensors measure phase changes and offer high sensitivity but require precise alignment and temperature stability.

Wavelength-based sensors support multiplexing and long-distance transmission but require complex wavelength analyzers.

Polarization sensors resist electromagnetic interference and environmental noise but need polarization-maintaining fiber and polarization analyzers.

In industry, fiber sensors are widely used for temperature, pressure, displacement, strain, flow, and liquid level monitoring. They perform well in high-temperature and strong electromagnetic environments, offer small size, light weight, high sensitivity, large bandwidth, and resistance to corrosion. They also enable distributed multipoint and remote monitoring, improving measurement efficiency and safety.