High Definition Fiber Optic Sensing (HD-FOS) uses optical frequency domain reflectometry to convert a standard unaltered fiber optic cable into a virtual continuous line of sensors to measure strain or temperature.  A distinct measurement can be made in 1mm increments along the length of fiber.  Altering the fiber with Bragg gratings in un-necessary and sensors can be constructed with standard cable. The fiber can be bonded to structures or in many cases embedded within them.

How It Works


  • Minute reflections from the fiber optic sensor are combined with reference light at the detector to “map” out the fiber
  • Temperature and strain changes along the length of the fiber can be measured by monitoring the spectral shift of these reflections


HD-FOS Interrogator and Sensor

Interrogator_sensorA typical HD-FOS system consists of an interrogator unit and fiber optic sensor.  The sensor is constructed from unaltered fiber optic cable and does not require fiber Bragg gratings.  The gage length and spacings are configurable through software and can be changed dynamically with the interrogator. 




  • A 150 micron fiber can measure strain in locations where strain gages can’t reach, including within structures
  • High density data is perfect for validating finite element models of critical components with fine mesh



Fiber optic cable is immune to EMI and is a dielectric.  A 150 micron fiber can measure strain in locations, where strain gages cannot reach, including within structures.