Fiber_Optic_Sensors.pdf

Fiber Optic Sensors

Properties, which can be sensed:

Displacement

Force

Liquid Level

Magnetic Fields

Motion

Temperature

Vibration

Position (linear, angular)

Pressure (fluid, gas, etc.)

Sound

Radiation

Speed

Weight

Pressure

How does a Fiber Optic Sensor work?

In a fiber optic sensor, one of the following characteristics of a propagating

lightwave is altered under an externally induced physical parameter:

Intensity

of light

Frequency

of light

Phase

of light

Polarization state

of light

Why are fiber optic sensors becoming so popular?

Small/lightweight

Allow access into normally inaccessible areas (often embedded)

Passive (non-electrical)

Highly sensitive

Easy to install

The Fabry-Perot fiber optic sensor.

Fabry-Perot Filter (interferometer)

The Fabry-Perot fiber optic sensor:

Principal applications:

Pressure, Strain, Temperature sensing etc.

Design of Fabry-Perot strain sensor:

Fiso, Inc. sensor: see www.fiso.com

Fiber optic Bragg grating temperature and strain sensors

Schematic diagram of fiber Bragg grating

Principle of operation of fiber Bragg grating:

Schematic of instrumentation for fiber optic Bragg

sensor.