Com&Sens engineer, produce and implement customized composites reinforced Fiber Bragg Gratings sensing tapes for harsh environments.
FIBER BRAGG GRATINGS MADE ROBUST
Embedded or surface mounted composites based fiber optic FBG sensors
FIBER BRAGG GRATINGS MADE VERSATILE
Designed for harsh environments
FIBER BRAGG GRATINGS MADE COST-EFFECTIVE
Fiber Optics becomes more cost-effective vs conventional strain gauges as of 8 sensors!
Yes, you can now forget your labour intensive strain gauges and thermocouples, and their associated wiring!
- Point Sensor
- Absolute sensor properties: no calibration needed
- Simultaneous readout of one fibre: 20 to 35sensors!
- Extensive sensor network
- Easy to install or to embed
FIBER OPTICS VS ELECTRICAL STRAIN GAUGES
FIBER BRAGG GRATINGS EXPLAINED
The FBG is a passive and discrete optical component at a specific spot in an optical fiber. An optical fiber consists of a fiber core and a fiber cladding. The Bragg grating is an area in the fiber core with a pre-defined length, Lg and an alternating periodic refractive index change, i.e. n1 ,n2 (Figure 1). An FBG acts as an optical filter or reflection filter and provides a frequency dependent reflection spectrum or stop band to the incident signal over a specific bandwidth. The stop band is centred at the Bragg wavelength, λB, and is given by the well-known Bragg condition , where ΛFBG is the grating period and n eff is the mode index or effective refractive index of the fiber.
Basic FBG strain sensing principle
The basic principle of strain sensing of a fiber Bragg grating is shown in Figure 2. When the fiber, having a nominal length, L0, is being elongated to a certain length L, the grating period will be strained and the refractive index of the fiber will change as well. As a consequence, a positive Bragg peak shift is induced from λB0 to λB . In fact, an FBG can be seen as the optical equivalent of a resistive strain gage (RSG). The basic principle of both types of sensor is the same: only one parameter will change when being strained. For an RSG, it is the resistance of the wire which changes as a function of strain and for the optical counterpart, it is the Bragg wavelength which shifts.