Fabrication of Long-Period Fiber Grating Using He-Cd Laser

Fiber grating, as an electro-optic component, has been used as a sensor in communications, Internet and various optical applications. The long-period fiber grating has been proved to be a useful optical component for source stabilization, strain gauges, and selective filters. This research develops an enhanced production method and studies the characteristics of long-period fiber gratings. A low power, dual band 325/442 nm, continuous wave He-Cd laser, substituting the conventional high power excimer laser with 248 nm, is employed as a light-source. Fiber gratings were fabricated ”point by point” using a computer-controlled process. Various long-period fiber gratings were produced with different exposure times and grating lengths. The transmittance spectra of the gratings were acquired by illuminating white light source. The derivation of the theory coincides with the spectra.