Microwave photonic filter free of spurious interference based on optical frequency comb

Abstract

The invention provides a microwave photonic filter free of spurious interference based on an optical frequency comb. The microwave photonic filter free of the spurious interference based on the optical frequency comb comprises an optical frequency comb source, a quadratic-form phase processing unit, a modulator, a dispersive medium and a photoelectric detector, wherein the optical frequency comb source is used for carrying radio frequency signals to be filtered, each carrier wave component corresponds to a tap in a transverse filter structure, the quadratic-form phase processing unit is used for adjusting the whole optical phase of the optical frequency comb source too be a quadratic form, the modulator is used for modulating the radio frequency signals to be filtered to each carrier wave component of the optical frequency comb source, the dispersive medium is used for introducing equal delay among all carrier wave of the optical frequency comb source and enabling each carrier wave in the optical frequency comb source to be regarded as one tap in the transverse filter structure, and the photoelectric detector is used for converting optical signals into electric signals and outputting the filtered radio frequency signals. The microwave photonic filter free of spurious interference based on the optical frequency comb can effectively suppress the spurious frequency and does not affect the characteristic that the filter transmits the function. Passband tuning can not be limited by the traditional Nyquist area. In addition, the microwave photonic filter free of spurious interference based on the optical frequency comb has the advantages of being simple in structure and wide in application range.

Description

technical field [0001] The invention relates to the research field of microwave photonic filters in microwave photonics, in particular to a stray interference-free microwave photonic filter based on an optical frequency comb. Background technique [0002] Microwave photonic filter refers to a technology that uses photonic technology to perform delay, weighting, summation and other operations on radio frequency microwave signals. Compared with electronic signal processing technology, photonic signal processing has the advantages of large time-bandwidth product, low loss, light weight, anti-electromagnetic interference and low loss. Compared with microwave filters based on electronic technology, microwave photonic filters can work in the high frequency range and have the advantages of large bandwidth and anti-electromagnetic interference. structure. [0003] At present, the transverse microwave photonic filter based on the delay tap of the optical frequency comb source, comp...

AI Technical Summary

Problems solved by technology

When the filter passband tuning is close to the boundary of Nyquist, there is very strong near-frequency interference in the output signal of the filter at this time, and the filter cannot work normally

Therefore, the limitation of the Nyquist zone greatly restricts the tunability and practical application of transverse microwave photonic filters based on optical frequency comb source delay taps

Images