Sensing and Demodulation of Special Long-Period Fiber Gratings Induced by Scanning CO_𝟐 Laser Pulses

Figure 15

(a) Transmission spectra of R-LPFG with grating period of 570 μm and twist period of 46 mm under different torsion, where “+” and “−” mean that the direction of the applied torsion is the same or opposite to that of the original twist applied to the fiber, respectively. (b) Wavelength separation of resonant peaks with respect to applied torsion [5].

(a)

(b)