Method of fabrication of 1D and 2D gratings

We propose an interferometric method of fabricating one-dimensional (ID) and two-dimensional (213) periodic structures in planar films and optical fibers. The central idea is to match the substrate or fiber translation velocity to that of the moving interference pattern so as to create its stationary image on the substrate or fiber. The moving interference pattern is produced by varying the relative phases of multiple interfering beams, and the pitch of the resulting structure depends on the frequency shifts between the beams. We apply the proposed method to writing ID and 2D periodic structures in photoresist layers on planar substrates and demonstrate the pitch control in the case of ID periodic structures. There is no limitation on the grating length, and grating designs can be arbitrarily complex optimized for use in both planar and fiber Bragg grating laser resonators.