Chip-based arbitrary radio-frequency photonic filter with algorithm-driven reconfigurable resolution

All programmable microwave photonic filters to date have been limited by the trade-off between the resolution and the operation bandwidth to construct arbitrary filter shapes. Here, we propose a new approach to synthesize a radio-frequency photonic filter with an arbitrary response and reconfigurable resolution through phase-only tailoring, which is implemented in a low-loss photonic chip. Based on an algorithm, incorporating the target transfer function of the filter optimum resolution can be intelligently chosen by tuning the coupling coefficients and the round-trip phase of cascaded ring resonators. We achieved filtering with tunable resolution from 300 MHz to 25 GHz along with various filtering shapes and multiple passbands. (C) 2018 Optical Society of America