Fiber Optic SensorFiber Optic Sensor

Fiber Optic Sensors

Can transmit light over long distances with very little loss of fidelity

Supports monitoring of landslides, bridges, bridge scouring, tunnels, and dams


Fiber Optic Sensors from Specto Technology

Specto Technology is your one source for Fiber optic sensors for Geotechnical and Structural Monitoring and are proud to provide you with:
Equipment Sales and support

  • Fiber Optic Sensor sales and support
  • Customized training for you and/or your subcontractors. Click here to view a list of training classes.
  • Best-in-class hosted data solutions to keep your data moving wirelessly from the field to your fingertips
  • Exceptional customer service and support

Product Features

  • Specially designed and built by highly skilled and experienced staff for geotechnical engineering applications with ease of installation and site deployment in mind
  • Available in many shapes and forms to measure temperature, strain, force, pressure, deflection, tilt, and displacement
  • System components including sensors, readout and datalogger (interrogator) are designed and built by Citpo in association with National Chiao Tung University in Taiwan

Product Benefits

  • Immunity to Electro-Magnetic Interference (EMI)
  • Immunity to lightning
  • Small and light weight
  • High resolution and high accuracy
  • High speed (capable of dynamic measurement)

Typical Applications Include

  • Monitor landslides, bridges, bridge scouring, tunnels, and dams
  • Monitor land settlement in Taiwan, China, the Netherlands and Singapore


Title Author(s) Year
Use of Optical Fiber Bragg Grating for Geogrid Strain Measurements Citpo Technologies Co. LTD. 2013
Fiber Optic Sensored Geotechnical testing and Field Monitoring A.B. Huang, Y.T. Ho, J.T. Lee & C.C. Wang 2013
Field Monitoring of Shield Tunnel Lining Using Optical Fiber Bragg Grating Based Sensors A.B. Huang, J.T. Lee, C.C. Wang, Y.T Ho & T.S Chuang 2013
Integrated Pore Water pressure and Displacement Profile Monitoring in Ground A.B. Huang, C.C. Wang, J.T. Lee & Y.T. Ho 2013
Integrated Pore water Pressure and Ground Subsidence Profile Monitoring A.B. Huang, J.T. Lee, T.S Chuang, Y.T Ho & C.C. Wang 2013
Characterization of Reservoir Sediment under Water with Differential Pressure Sensored Flat Dilatometer and Piezo-Penetrometer J.T. Lee, C.C. Wang, Y.T. Ho & A.B. Huang 2013
Ground Stability Monitoring with Pore Water Pressure and Displacement Profile Measurements A.B. Huang, J.T. Lee & Y.T Ho 2012
Soils and Foundations – Stability Monitoring of Rainfall Induced Deep Landslides Through Pore pressure Profile Measurements J.T. Lee, A.B. Huang, Y.T. Ho & Y.F Chiu 2012
A Fiber Optic Sensored Triaxial Testing Device J.T. Lee, K.C. Tien, Y.T Ho & A.B. Huang 2011
Recommended Layout of Instrumentation to Monitor Potential Movement of MSE Walls, Berms and Slopes Robert M. Koerner, Ph.D., P.E., NAE & George R. Koerner, Ph.D., P.E., CQA 2011
Field Monitoring of Pore Water Pressure Profile in a Slope Subjected to Heavy Rainfalls A.B. Huang, J.T. Lee & Y.T Ho 2009
Contribution of Fibre-optic Geosynthetic Instrumentation for the Monitoring of Rehabilitated Failed Slope K.H. Loke & D. Montri 2009
Development of a Chirped / Differential Optical Fiber Bragg Grating Pressure Sensor Y.T. Ho, A.B. Huang, J.T. Lee 2008
Development of Optic Fiber Bragg Grating Displacement and Pressure Sensors A.B. Huang, Y.T. Ho & J.T. Lee 2007
Safety Monitoring of the Yellow River Dike – A Feasibility Study on Various Instrumentation Schemes Ma Jiming, Zhang Baishan, Cao Jingang & A.B. Huang 2007
Development of a Fiber Bragg Grating Sensored Ground Movement Monitoring System Y.T. Ho, A.B. Huang & J.T. Lee 2006
Field Monitoring of Pore Water Pressure Profile in a Slope Subjected to Heavy Rainfalls A.B. Huang, J.T. Lee & Y.T. Ho 2006
Ground Movement Monitoring Using an Optic Fiber Bragg Grated Sensored System Y.T. Ho, A.B Huang & Ma Jiming 2005
Monitoring Displacement Distribution Within the Rock Mass During a Plate Load Test A.B. Huang, J.J. Liao, I.W. Pan & C.P. Lin 2003
Geotextile Strain in a Full Scale Reinforced Test Embankment R. Kerry Rowe & C.T. Gnanendran 1994
Fiber optic instruments are rapidly becoming more affordable and have numerous technical advantages over traditional sensors. Specto Technology is proud to partner with Citpo Technologies in Taiwan to offer a range of FBG based fiber optic sensors to our customers. Optical fibers are made of silica (just like glass), with a diameter about the same as a human hair, and can transmit light over long distances with very little loss of fidelity. Optical fibers comprise two essential components: a core surrounded by an annular cladding. The core of the optical fiber serves to guide light along the length of the fiber. The cladding has a slightly lower index of refraction than the core and its primary function is to ensure total internal reflection within the core so that very little light is lost as it propagates along the optical fiber. The typical combined diameter of core and cladding is 125 µm (125 x 10-6 m). The silica core/cladding is protected by an acrylic coating. The total outside diameter of an optical fiber with the acrylic coating is 250 µm. By adopting technologies from telecommunication, many fiber optic based sensing techniques have been developed. These sensors have been used in medical, defense, aeronautical, and civil engineering industries. In recent years, development and application of fiber optic sensors are expanding rapidly Fiber Bragg grating (FBG) is one of the more common and better developed fiber optic sensing technologies. An FBG is made by exposing a 1 to 20 mm long, single mode optical fiber to an ultraviolet light through an optical waveguide, thus creating a “periodic variation” of refractive index in the fiber core (it’s like creating a hologram in glass). When the FBG is illuminated by a wideband light source, a portion of the light is reflected back upon interference by the FBG. As the longitudinal strain within the FBG changes, the wavelength of the reflected light will shift in proportion with the changes in strain. A typical commercially available FBG system can detect a shift of wavelength as small as 1 picometer (10-12 meters).