Study on the time delay of uniform fiber Bragg gratings

The time delay of the light reflected from and transmitted through the uniform fiber Bragg grating (FBG) are computed and shown to be equal. The physical meaning of the time delay is discussed based on tunneling effect and energy storage function of the FBG. The energy density of the optical field distributed along the FBG and the total energy stored in the FBG are calculated based on the coupled mode theory (CMT). The time needed for light to form the stable energy density distribution is computed and shown to be equal to the time delay of the FBG.