Strain sensors with no temperature compensation (OSS series)


Fiber strain sensors of the OSS series based on fiber Bragg gratings (FBG) are used for long-term and reliable measurement of the strain of the object to which they are attached. If the sensor is securely attached to the surface of the object being diagnosed, the fiber with FBG is strained in the same way as the area of the object under consideration. The recorded value is the FBG resonance wavelength, which the relative change is proportional to the total strain (both mechanical and temperature-induced) of the surface. Only one FBG is used in the OSS sensors to measure strain. To take temperature-induced Bragg wavelength change an additional temperature sensor is required. Our FBG-based temperature sensors of 311 series are well suited for this purpose.

Note that in strain sensors of the OSST series, an additional FBG that measures temperature is located directly in the sensor body near the deformable grating (an additional FBG is formed in the same fiber and has a different resonant wavelength). Thus, the use of two FBGs allows simultaneous measurements of strain and temperature.

OSS sensor bodies are made of cryogenic austenitic stainless steel 316L, which is resistant to corrosion in aggressive environments and retains mechanical characteristics over a wide temperature range.

The spectral shift of the resonant wavelength of the FBG sensor can be recorded by any FBG interrogator. For this purpose, our company offers a line of interrogators - unified recording modules (URM) - that provide an aquision and processing of spectral information of FBG sensors with subsequent output of the results to the operator.

The FORC-Photonics OSS sensors have the following:

  • spectral multiplexing
  • possibility of remote measurements (no power supply requires at the measurement site)
  • long-term stability of measurements
  • immunity to electromagnetic interference
  • fire safety
  • small dimensions and weight
  • wide range of strain and temperature measurements
  • low error level within the entire measurement range



Strain sensors developed and manufactured by FORC-Photonics are designed for long-term operation in an extended temperature range, including elevated temperatures (up to 350C). This is ensured by the use of heat-resistant optical fibers, Bragg gratings and other parts of the sensor. OSS sensor is attached to a flat metal surface using spot or TIG welding.



  • strain measurements at elevated temperatures (up to 350°C).
  • high accuracy and long-term stability
  • fast response time
  • high accuracy of calibration combined with an application of simplified calibration equations
  • measurements can be performed using most FBG interrogators.
  • robust and high-temperature performance of the fiber cables and optical connectors
  • ease of installation using standard fittings




Волоконные датчики деформации серии OSS на основе волоконных брэгговских решеток (ВБР)






OSS - 531

OSSM - 531 OSSH - 531
Thermal characteristics
Strain measuring range, µm/m  ± 2500
Accuracy in the entire range, µm/m ± 30
Temperature measuring range, ºС -40 ÷ +150  +300
Optical characteristics
Resonance wavelength, nm  1510 ÷ 1590
Peak reflectivity, % ≥ 60
FWHM, nm 0.3 ÷ 0.4
Fiber type compatible with SMF-28
Connector type (on request) without connector, FC/APC, LC/APC, SC/APC
Mechanical characteristics
Sensor body size, mm 30 х 15 х 1.1
Attachment method spot or TIG welding
Type of measuring deformation Relative
Sensor body material SS 316L
Optical fiber protection material  silicon steel tube
Cable length, m 1 (both side)

 Fiber-optic strain sensor OSS series