Novel microwave optical filter design employing fiber Bragg grating arrays

We propose a novel microwave optical filter design method employing fiber Bragg grating arrays and optimal filter design. In the proposed system, the grating arrays are used to provid different delays. Each of the grating arrays is connected with an adjustable attenuator that sets the weighting of the tap. Both negative and passive coefficients can be obtained by differential detection structure presented in the system. Tuning is realized by changing the optical carrier wavelength to select the operating gratings. We at the first time adopt linear phase structure in the microwave filter design, which simplifies the design configuration. Optimal filter design method is creatively adopted to optimize weightings of grating arrays. It is superior to window function method and can realize the total control of filter specifications. Furthermore, experiment has been conducted to confirm above conclusions. The results show that our method solves some pivotal problems and is an effective way to design microwave optical filters.