What is fiber-optic temperature sensor and their ranging temperature


Temperature sensors based on optical technology, most frequently fiber optics, are referred to as optical temperature sensors. Specifically, electronic temperature sensing is one of the alternatives. Fiber optical temperature sensors, however, can provide a lot of benefits. Fibre optic sensors for temperature measurement do not require electrical wires, may function over an extensive temperature range, and are immune to electromagnetic interference. Fiber optic temperature sensors can be embedded and installed where traditional temperature sensors cannot and are resistant to many environmental effects that affect other measurement technologies. It delivers unprecedented distance detail and data without compromising precision and sensitivity. 

Below you can see the fiber-optic temperature measurement and its ranging temperature:

What is fiber-optic temperature sensor measurement? 

Fibre optic sensors for temperature measurement are examined based on gallium arsenide’s light transmission or absorption properties. Temperature variations have well-known and predictable effects on this semiconducting crystal. A GAAs crystal is located at the fiber optic temperature sensor’s measurement end. The crystal’s transmission spectrum moves to longer wavelengths as its temperature rises. Transmission at a certain wavelength jumps from 0% to 100% at any given temperature. The absorption shift is the name for this jump. The temperature and the precise wavelength at which the absorption shift occurs have a very predictable relationship.

 Benefits of fiber optic temperature sensor 

The advantages or benefits of a fiber optic temperature sensor are as follows:

  • It is resistant to EM and stray radiation in the area.
  • It applies to situations with high electrical interference levels or uncertain intrinsic safety.
  • Using fiber optic sensors for temperature measurement gives you greater accuracy (+/- 1o) and a quicker response time.
  • It is manageable because it is small and lightweight.
  • Due to low manufacturing costs, it is less expensive.
  • It can measure temperatures in the vast range of -10 C to 300 C. Better temperature-dependent wavelength fluctuation is provided by GAAs.


Using fiber optic sensors for temperature measurement will help emit a monochromatic light source. The beam emanating from the laser source is split into two beams, the main beam and the split beam, which are precisely at right angles by the beam splitter maintained at 450 inclination. The reference fiber, which is isolated from the environment to be sensed, is the object of the main beam once it has passed through lens L1. The beam strikes Lens L2 after traveling through the reference fiber.

The split beam is directed onto the test fiber kept in the environment to be detected after passing through Lens L3 and splitting. After passing through the test fiber, the split beam is made to fall upon lens L2. Due to changes in environmental variables like pressure, temperature, and others, the two beams’ paths diverge after passing through the fibers. As a result, the interference is caused by a route difference between two beams. Consequently, using the acquired interference pattern, it is possible to quantify changes in pressure or temperature accurately.

 High-definition distributed temperature sensing 

With a sub-millimeter spatial resolution, high-definition temperature sensing based on optical fiber’s inherent Rayleigh backscatter of fiber optic sensors for temperature measurement produces nearly continuous lines of temperature measurements.

  • Using high spatial resolution, visualize temperature profiles
  • Flexible fiber sensors that are compact and light
  • It has up to 100 m per channel for distributed sensors

 Multipoint temperature measurement 

A single optical fiber sensor network can multiplex and distribute Bragg grating-based strain readings over a vast region.  

  • Temperature sensor using a fiber Bragg grating.
  • Multiple point sensors can be combined on a single fiber channel.
  • Alternatives for robust and flexible temperature sensors that are packaged for simple installation.

Long-Range distributed temperature sensing with Optasense

The opta sense extended-range distributed acoustic sensing interrogators of fiber optic sensors for temperature measurement provide the best interrogator systems for all types of distributed fiber optic sensing applications by providing long-range quantitative data performance with high fidelity and sensitivity.

  • Monitor temperature and strain with high sensitivity and low noise floor.
  • Quantitative data up to 50 km long.
  • Cable gauge lengths from 2 m to 35 m, range of ping rates, and acquisition possibilities from 2 km to 200 km.


When choosing fiber optic proximity sensors, there are a lot of features to keep in mind.

  • Field-adjustable sensors are necessary when modifications must be made while the proximity sensor is in operation. 
  • To regulate the detecting range, potentiometers are frequently employed.
  • Auto-calibrated self-teaching proximity sensors can be programmed to activate the switch at a predetermined target location.

Parting words

Compared to other measurement technologies, fiber optic temperature sensors for temperature measurement are unaffected by various external factors. It may be embedded and deployed in places where conventional temperature sensors cannot, providing unprecedented spatial resolution and data without losing accuracy and sensitivity.

Leave a Reply

Your email address will not be published. Required fields are marked *