Design of an Edge Filter Based on a Phase-Only Modulated Long-Period Fiber Grating

An efficient edge filter with an ultrabroad dynamic range is first proposed and numerically demonstrated, which is achieved by using a phase-only modulated long-period fiber grating (LPG). As a typical design example, an edge filter with a linear dynamic range of similar to 50 nm in wavelength and similar to 85% in transmission loss has been successfully obtained, which are the best results reported to date among those of the fiber grating based edge filters. Fabrication tolerance analyses for the designed filter have also been performed. The simulation results show that the designed filter can be practically fabricated according to the position accuracy (+/- 1.5 mu m) of the current LPG's fabrication platform.