DTG®s in low bend loss fiber
Draw Tower Gratings (DTG®s) written in Low Bend Loss fiber LBL-1550-125 which has a cladding diameter of 125µm and is optimized for operation in the 1550nm wavelength window. The glass composition has been tuned such that the fiber maintains a good signal transmission under small bending diameters.
Draw Tower Gratings (DTG®s) written in Low Bend Loss fiber LBL-830-125 which has a cladding diameter of 125µm and is optimized for operation in the 830nm wavelength window. The glass composition has been tuned such that the fiber maintains a good signal transmission under small bending diameters.
DTG®s in reduced cladding fibers
Draw Tower Gratings (DTG®s) written into Low Bend Loss fiber LBL-1550-80 which has a cladding diameter of 80μm and is optimized for operation in the 1550nm wavelength window. The reduced cladding diameter offers several major advantages compared to standard 125µm fibers:
- Unobtrusiveness – particularly interesting for embedding applications including carbon composite structures and medical catheters.
- Increased sensitivity – less force is required to strain the fiber enhancing the performance of sensors based on force or acoustic sensing.
- Reduced bending radii – lower surface strain levels enabling more compact sensor designs.
|Parameter||Low Bend Loss Fiber 1550-125||Low bend loss fiber 830-125||Reduced cladding fibers|
|Reflectivity (for grating length of 8mm)||> 15%|
|FWHM (for grating length of 8mm)||100 pm||30 pm||100 pm|
|Centre wavelength (extended range upon request)||1510–159 0 nm||1460–1620 nm||810–860 nm||1510–159 0 nm||1460–1620 nm|
|Absolute wavelength accuracy¹||≤ 0.5 nm||≤ 0.8 nm||≤ 0.5 nm||≤ 0.5 nm||≤ 0.8 nm|
|Relative wavelength accuracy||≤ 0.3 nm||≤ 0.5 nm||≤ 0.3 nm||≤ 0.3 nm||≤ 0.5 nm|
|Side Lobe Suppression (SLS)||≥ 10 dB (typical)|
|DTG® length||2–10 mm / 8 mm (typical)|
|Attenuation||< 8.6 dB/km||< 18.4 dB / km||< 8.6 dB/km|
|Mode Field Diameter (MFD) @ 1550 nm||6 μm (typical)||5 μm (typical)||6 μm (typical)|
|Numerical Aperture (NA)||0.26 (typical)|
|Cladding diameter||125 μm ± 1 μm||80 μm ± 1 μm|
|Coating type²||ORMOCER®/ORMOCER®-T / One layer Acrylate|
|Coated fiber diameter||195 μm (typical)||120 μm (typical)|
|Tensile load at break³||> 50 N (corresponds to >5% strain)||> 20 N (corresponds to >5% strain)|
|Temperature sensitivity⁴ (formula: Δλ/(λ ⋅ ΔT) )||6.5 K-1 ⋅ 10-6 (typical)|
|Strain sensitivity¹ (formula: Δλ/(λ ⋅ Δε) )||7.8 με-1 ⋅ 10-7 (typical)|
|Operational temperature range||-200–200°C for ORMOCER®|
|-20–200°C for ORMOCER®-T|
|-20–90°C for One layer Acrylate|
1 measured at room temperature
2 ORMOCER® is mainly applied for strain measurements while ORMOCER®-T is recommended for temperature measurements.
3 according to IEC-60793-1-31 using a constant displacement of 30 mm/minute
4 measured between 0°C and 70°C
5 Temperature range is dependent on exposure time.
ORMOCER®: trademark of Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.