A study on a long period fiber grating pair's spectral characteristics

This paper demonstrates the spectrums of a long period fiber grating pair (LPGP) by changing the following physical parameters: the separation of the LPG, the length of single LPG and the number of single LPG .The study of the response of the LPGP to different parameters enables a rational design of the sensor element. These results produce an important foundation of our further study of LPGP spectral characteristics. On the basis of the above conclusion, a LPGP is produced by the amplitude mask method, in which the germanium-doped fiber is exposed by the UV. The LPGP's resonance wavelengths are shifted as the refractive index of medium surrounding the cladding of the long-period grating. The sugar solution was experimentally measured, and results show that, this fiber-based device can rely on LPGP's the wavelength drift to differentiate solution's concentration based on their refractive index.