Sensing characteristics of long-period fiber grating fabricated by 800nm femtosecond laser pulses

In this paper, the long period fiber gratings (LPFGs) in standard SMF-28 telecommunication fibers without hydrogen loading were inscribed by using direct writing method of femtosecond laser pulses with pulse duration of 100 fs, repetition rate of 1kHz and a central wavelength of 800 nm. The transmission spectrum dependence on grating length was demonstrated experimentally. The loss peak of 1320 nm, the transmission loss of 13.9 dB, the out-of-band less of 1dB and the FWHM of 30 nm were obtained. Further, temperature and bending dependence of wavelength shift in air was discussed.