Tunable and reconfigurable microwave photonic filter based on Fourier domain optical processor and cascaded fiber rings

Abstract

A tunable and reconfigurable microwave photonic filter (MPF) based on a Fourier domain optical processor (FD-OP) and cascaded fiber rings is proposed and demonstrated. A stable and multiple wavelengths source can be realized by using a broadband source and a waveshaper. The multiple wavelengths source with different wavelength spacings is achieved by programming the waveshaper. Two fiber rings of the same structure are cascaded together to achieve a high main sidelobe suppression ratio (MSSR) and a high Q factor. The FD-OP is induced to add additional phase shifts to achieve tunability. When the number of taps is 60, by introducing cascaded two-fiber rings and the FD-OP, the MSSR is 59.356 dB, the maximum Q factor is 470.895 and the 3dB bandwidth of the filter is 0.019 GHz. The simulating results show that the center frequency continuously tuned from 4.47–13.41 GHz. The tunability and reconfigurability of the MPF are well realized.