Flexible interference lithography using fibers as laser beam splitting and delivering system is demonstrated. A laser beam at 325 nm is used as the ultraviolet light source. Fiber bundles consisting of two, three, or four optical fibers have been utilized for the fabrication of two-dimensional photonic structures with different lattice configurations and different periods. The effective area of the fabricated waveguide grating structures is in the scale of centimeters in diameter with excellent homogeneity, which has much space for further improvement. This flexible interference lithography technique enables simple, compact, and efficient fabrication of photonic structures.