ADVANTAGES OF FIBER OPTIC SENSORS
- Immune to electromagnetic interference and suitable for explosive and nuclear environments
- Multiple parameter sensing per cable / channel (temperature, strain, bending, tension, pressure, vibration, acoustics)
- High sensitivity and fast measurement responsiveness
- Unrivalled high spatial sensing resolution
- Minimum cabling and space requirements
- Long-distance monitoring without amplification (>20km)
- Intrinsically passive (no electrical power required)
- Accurate and distributed temperature profiles can be measured in real time
The FBG is an optical filtering device that reflects light on a specific wavelength and is located within the core of an optical fiber waveguide. Due to the wavelength dependence on temperature and strain, FBGs are widely used for optical sensing.
FemtoFiberTec uses a special inscription technology for FBGs, based on infrared fs-laser technology.
The laser is focused into the core of the fiber and induces local refractive index changes in a point-by-point writing process. The process is highly nonlinear and therefore basically independent of the fiber material, which means that doping the fiber is not required. The FBGs can be written in radiation insensitive fibers and special pure core fibers for harsh environments. The gratings are type II gratings that withstand temperatures of up to 1,000°C.
As the process is applied through the coating of the fiber, no stripping and recoating is required, resulting in superior tensile strength of the FBGs.
BENEFITS OF FS-LASER-FBGs
compared to conventional FGBs
- Type II gratings survive temperatures of up to 1,000°C, compared to UV-inscribed FBGs which fade-out at approx. 250°C
- Highly cost efficient multipoint/ sensor array production
- Immunity to humidity and radioactivity
- Significantly higher tensile strength compared to strip and recoat technology
- Low polarization (0-5pm) for high resolution measurements compared to draw tower gratings and very low scattering losses (< 0,2dB)
- Significantly higher reflectivity and lower fiber cost compared to draw tower technology
- Highest spatial resolution due to dense sensor spacing (minimum FBG distance 2mm)
- Direct writing process into customer specific fibers possible
- Industry leading specification variety
The fully automated manufacturing technology provides the highest possible flexibility in terms of customer individual FBG specifications and production volumes - from one up to thousands of units. Furthermore, customer orders are produced within shortest lead times in the industry.