A novel fabrication technique of long period fiber gratings using a holographic optical element

We develop a new flexible and precise ultraviolet exposure technique to fabricate a long period fiber grating using a computer-generated holographic optical element (HOE). The HOE can generate a striped beam pattern with about a 300 mum period from a KrF excimer laser. This method offers (1) ease in varying the grating period and (2) grating period precision. We achieve a grating period within an accuracy of +/- 0.04 mum. This means that the peak wavelength can be controlled within an accuracy of +/- 0.2 nm with an operating wavelength of 1.55 mum.