Fiber optic sensing uses the physical properties of light as it travels along a fiber to detect changes in temperature, strain, and other parameters

1. Fiber optic sensing

2. What is Fiber optic sensing?
• Fiber optic sensing uses the physical properties of light as it travels along a Fiber to detect
changes in temperature, strain, and other parameters.
• Fiber optic sensing utilizes the Fiber as the sensor to create thousands of continuous
sensor points along the Fiber. This is called distributed Fiber optic sensing using a
distributed Fiber optic sensor.
• The purpose is to use a standard or specific Fiber for measuring the temperature and
strain along it using Raman and Brillouin Distributed Fiber Optic Sensor techniques.

3.  Detect and locate any hot spot along your power cable.
 Detect and locate any excessive strain on your optical cable and
react before the break.

4. Fiber sensing applications:

5. How does Fiber sensing work?
• Extrinsic sensing is the process of communicating with an external
sensor via a test station over a Fiber optic cable. Intrinsic Fiber
sensing, on the other hand, occurs when the Fiber itself serves as the
Fiber optic sensing system.
• To yield relevant information, the light source inside the cable must
be affected by external stimulation in a measured way, such as
temperature and strain changes.

6. Distributed Fiber optic sensing
• In this context, “distributed” simply refers to Fiber sensing technology that can measure continuously throughout the
complete length of the Fiber, or distributed Fiber optic sensor.
• Since these Fiber sensing methods are completely intrinsic, standard telecommunications Fiber can be used as the
medium, if the temperature is expected to remain below 100˚C (212˚F), and the Fiber is not subjected to excessive
chemical or mechanical disruption.

8. How Fiber sensing evolved
• The evident promise of fiber for sensing applications was already
being appreciated before fiber optics had come onto the picture as a
telecommunications technique in the 1970s.
• A non-contact fiber extrinsic sensor called the fotonic sensor was first
patented in 1967. The fundamentals of fiber optic gyroscopes were
developed by the middle of the 1980s.
• Accurate rotational data could be obtained by monitoring the laser
light source's phase shift inside the fiber.

9. Several infrastructure monitoring applications
 Detection of ground movement along a pipeline
 Detection of mechanical deformation of the pipeline
 Detection and location of any leakage along a pipeline, dike, dam etc.
 Detection and location of any critical point in a telecom optical network
 Detection and location of any hot spot along a power cable

11. Type of Fiber optic sensing interrogators
 DTS (Distributed Temperature Sensing) based on Raman OTDR technology
 DTSS (Distributed Temperature and Strain sensing) based on Brillouin OTDR technology

12. DTS (Distributed Temperature Sensing) based on
Raman OTDR technology
• Brillouin OTDR (BOTDR). Ashort pulse of light is launched into thefiber used as afiber
optic sensor. The forward propagating light generates Brillouin backscattered light at
two distinct wavelengths, from all points along the fiber.
• The wavelengths of the Brillouin backscattered light are different to that of the forward incident light and are
named “Stokes” and “anti-Stokes”. The difference of Stokes and Anti-stokes Brillouin level and frequency is
an image of temperature and strain along the fiber

14. Fiber testing shorten repair (MTTR) of critical infrastructure
• Any changes are immediately alerted to through fibre monitoring. The
location of the incident identified on the fibre can also be pinpointed
on a geo-located map using this method.
• This cuts down on the amount of time it would take to detect an issue
along a fibre and enables the organisation to dispatch to check the
fibre or fix to the proper area each time. study up on fibre testing.