Introduction to Fiber Optic Sensor

by www.fiber-mart.com

In recent years, fiber optic sensor has been deployed successfully in the supervision of structures. Because it is immune to electromagnetic interference and can handle extreme conditions, so it is gaining popularity as the sensor of choice for many industries. Fiber optic sensor is a sensing device that converts light rays into electronic signals. It is usually used for measuring physical quantities such as temperature, pressure, strain, voltages and acceleration etc. This blog is to introduce fiber optic sensor’s classification, characteristics and applications.

 

Classification
Fiber optic sensor can be mainly classified by sensing location, operating principle and applications. Depending on location of sensor, there are intrinsic and extrinsic fiber optic sensors. Considering the operating principle and demodulation technique, fiber optic sensors can be further divided into intensity, phase, frequency and polarization sensors. Based on application, fiber optic sensors can be classified in physical, chemical, bio-chemical sensors.

 

Characteristics
Fiber optic sensor offers unique characteristics that make it very popular and sometimes become the only viable sensing solution. Some inherent characteristics of fiber optic sensor are shown as following:

Harsh environment stability to strong electromagnetic interference immunity, high temperature and chemical corrosion, as well as high pressure and high voltage etc.

Very small size, passive and low power.

Excellent performance such as high sensitivity and wide bandwidth.

Long distance operation.
High sensitivity.

Multiplexed or distributed measurements – which are used to offset their major disadvantages of high cost and end-user unfamiliarity.

Applications
Fiber optic sensor has a variety of applications that can be found in equipment from computers to motion detectors. Several applications are specifically shown as following:

Mechanical Measurement – such as rotation,acceleration, electric and magnetic field measurement, temperature, pressure, acoustics,vibration, linear and angular position, strain, humidity, viscosity etc.
Electrical & Magnetic Measurements

Chemical & Biological Sensing
Monitoring the physical health of structures in real time.
Buildings and Bridges – concrete monitoring during setting, crack monitoring, spatial displacement measurement, neutral axis evolution, long-term deformation monitoring, concrete-steel interaction and post-seismic damage evaluation.

Tunnels – multipoint optical extensometers, convergence monitoring, shotcrete vaults evaluation, and joints monitoring damage detection.

Dams – foundation monitoring, joint expansion monitoring, spatial displacement measurement, leakage monitoring, and distributed temperature monitoring.

Heritage structures – displacement monitoring, crack opening analysis, post-seismic damage evaluation, restoration monitoring, and old-new interaction.

Detection of Leakage