Radiation-mode coupling loss in tilted fiber phase gratings

We demonstrate that grating tilt is an important adjustable parameter that can be utilized in addition to the more familiar parameters of grating length and index change to tune the spectral shapes of fiber phase gratings designed to perform demanding filter applications through guided-mode to radiation-mode coupling loss. A comparison is made between calculated transmission spectra obtained from a coupled-mode-theory analysis and measured spectra obtained from strong gratings written by ultraviolet irradiation of deuterium-sensitized fiber with grating tilt angles ranging from 0 degrees to 15 degrees . We show that good agreement is obtained between the experimental measurements and the theoretical predictions.