The Investigation About Microwave Photonic Filter And Phase Shifter

Microwave photonics can be defined as a subject which research the optical devices that apply to the microwave frequency,and the applications to optics or the microwave system.Because of the advantages of the microwave photonics,such as,low loss and immunity to electromagnetic interference,realizing high bandwidth,overcoming the inherent bottlenecks of electronic techniques,it will own a luciferous future.In this paper,we studied the microwave photonic filters and the microwave photonic phase shifters,it mainly consists the following contents:(1)group delay response design for the finite impulse response microwave photonic filters.We propose the reason for the group delay about microwave photonic filter: microwave photonic impulse response is whether symmetry,firstly.By means of simulation and experiment,we verified this conclusion.(2)The design for a novel wideband microwave photonic phase shifter.We propose a novel wideband microwave photonic phase shifter techniques which based on dual-parallel Mach Zehnder modulator and a tunable optical polarizer,full phase shift range from-180° to 180 °can be realized with a flat amplitude response.It significantly improved the performance of microwave photonic phase shifter at lower frequency.(3)Ripple suppression in broadband microwave photonic phase shifter frequency response.At first,we found out the reason about the ripple: 90° hybrid coupler amplitude and phase imbalance.Then,we propose the solution: using a low-cost and low-loss optical filter to suppress the ripples in the microwave photonic phase shifter frequency response.Finally,experimental results demonstrated that by incorporating an optical filter in the phase shifter structure can reduce the amplitude variation and phase deviation from 4.2 dB to 2.2 dB and from ±12° to ±3.8°respectively over a wide frequency range.