瞬态光学研究室知识库

Based on the photoelastic effect, a new technology is used to fabricate high quality microtapered long period fiber gratings (MLPFGs) from microfibers. The effects of different periods and number of tapers on the grating spectrum have been explored. The high temperature characteristics of the grating were studied. The results show that MLPFG fabricated from a microfiber has good high temperature stability. With the increase of temperature, the spectrum of grating with a period of 685 mu m has the same change trend as that of grating with a period of 670 mu m. The temperature sensing sensitivities of gratings with periods of 685 mu m and 670 mu m are 0.0203 nm degrees C-1 and 0.01741 nm degrees C-1, respectively. The critical temperature at which the spectrum of the fabricated MLPFG changes irreversibly is between 600 degrees C and 800 degrees C, which is more than 100 degrees C higher than that reported previously. Another advantage of this type of grating is that it can be used to make torsion sensor. The measurement range is larger than that of grating directly tapered from a single mode fiber (SMF). By observing the shifts of resonant wavelengths, the torsion angle can be determined without taking other measures.