Modeling and fabrication of long period grating using ultrafast laser point by point writing

Long Period Gratings (LPGs) are a type of optical fiber grating sensor with higher sensitivity than more popular Fiber Bragg gratings. This work details the simulation and fabrication of femtosecond laser point-by-point writing of LPGs in Corning SMF-28 telecommunication fiber. These sensors are employed for temperature sensing and demonstrate a transmission dip center wavelength temperature sensitivity of 12.4 pm/°C. Wavelength-dependent amplitude change is also observed, with a peak shift of -0.005 dB/°C. The effect of writing power on transmission characteristics is investigated as well.