Fiber Bragg Grating Engineered Temperature Sensor (FBG-ETS)

A FBG can be made onto different photosensitive fibers with jacket material, such as acrylate, polyimide, and metal. The periodic modulated refractive index can be uniform inscribed in the fiber core as regular FBG. To inscribe a grating onto the fiber core, the jacket material has to be removed. The usual stripping length of the jacket material is typical from 10mm to 15mm. The grating length has a typical length of 5-10mm. A typical FBG spectrum has a peak that can be up- or down-shifted by thermal effect. After a calibration process, a FBG can be used as a temperature sensor.

1fbg_spc

Note: Our FBG manufacturer has full License Agreement from CRC/UTC Fiber Bragg Grating Technologies Portfolio for FBG and sensor fabrications.

Boston Instruments FBG engineered temperature sensors are based on packaged FBG elements that are designed for high-magnetic, high-voltage, high-current, microwave, and radioactive environmental applications. The packaged FBG-TS has a specific temperature sensitivity of ~10pm/°C. For different environmental application, the package material could be flexibly chosen to meet the maximum operation temperature requirement. These packaged FBG temperature sensors will be connected with a fiber cable either with fire-resistant Kevlar or with Inconel/Stainless steel based armoured cable. Here are seven types of FBG based temperature sensing cables:

  • Model: FBG ETS-180 (Standard bared fiber snesors, 180°F)
  • Model: FBG-ETS4K (Fiber silica sleeve protected cryogenic temperature sensors, 4K-500K )
  • Model: FBG-ETS-370T (Teflon tubing protected fiber sensors, 370°F)
  • Model: FBG-ETS-570S (Fiber silica sleeve protected fiber sensors, 570°F)
  • Model: FBG-ETS-570P (Polyimide capillary sealed fiber sensors, 570°F)
  • Model: FBG-ETS-1000SS (Stainless steel capillary sealed fiber sensors, 1000°F)
  • Model: FBG-ETS-1500C (Ceramic capillary sealed fiber sensors, 1500°F)

To assist sensing cable installation in a specific application, such as in an oil transformer, we can customize the sensor package geometry and associated fiber cable either for mechanical protection or for electromagnetic immunity requirement. These temperature sensing cables could be mounted by adhesive bonding, welding, or clamping. A typical fiber temperature sensing array with n FBGs actually consists of three parts. First is sensing line where the FBGs are inscribed with a spacing >0.5 Inch (12.5mm). Second part is package material, which provides fiber sensor protection against installation damage. Third part is called as "transmission line", which is transmitting singal between the interrogator and FBGs. Normally, a 3mm diameter (yellow) cable is used for such a signal transmission with a typical length of 2 meters. However, this transmission line cable could have other package material such as silica sleeve for 1000°F, Teflon capillary for 370°F, Polyimide capillary for 570°F, stainless steel capillary for 1000°F, and ceramic capillary for 1500°F harsh environmental installation. BI will provide a best package material recommendation to customer based on application conditions. For quote purpose, customer can specify exact lengths by referencing this typical fiber sensing cable diagram.

FBG_TEMP_SENSOR

FBG sensor_linear_error

Specifications

E-TEMP_SENSOR_SPEC

BI's FBG temperature sensing cable can be designed for high-magnetic, high-voltage, high-current, microwave, and radioactive environmental applications. To assist customer application installation these wire like sensors could be mounted by adhesive bonding, welding, or clamping methods. Specifically, the fiber sensing cable is packaged with Inconel 625/718/825 or 304L/316L stainless steel sheath for harsh environmental deployment, while the PTFE/Teflon capillary based package could be used for electrical motor/generator high-voltage/high-current environmental deployment.

Download: FBG Temperature Sensor  (0.67 MB PDF)

To meet different demands from customers, we can customize fiber sensing cable by using specific package material and fabrication method. When you place your order, please specify your specific requirements to our sales department at: sales@bostoninstruments.com