Microwave photonic down-conversion apparatus and method based on bidirectional cyclic frequency shift

Abstract

The invention discloses a microwave photonic down-conversion apparatus and method based on a bidirectional cyclic frequency shift, and relates to the field of microwave photonics. The microwave photonic down-conversion apparatus and method aim to solve the defects of small bandwidth, large loss and the like confronted by a traditional electrical frequency converter and the defect that high-frequency electrical local oscillation is needed by an optical frequency conversion technology. The apparatus provided by the invention consists of a laser, a cyclic frequency shift module and a photoelectric detector; and the cyclic frequency shift module includes a 2*2 optical coupler, a polarization controller, a dual-drive electro-optical intensity modulator, an electrical local oscillation source, an optical amplifier, an optical band pass filter and an optical adjustable delay line. In the cyclic frequency shift module, first-order optical sidebands of a to-be-converted radio-frequency signal and an electrical local oscillation signal on an optical carrier simultaneously perform opposite optical sideband movement step by step at a same frequency shift, and at last photoelectric detection isperformed on two opposite frequency shift optical sidebands having nearest frequencies to implement down-conversion of the radio-frequency signal; and with the characteristic of opposite frequency shift of the cyclic frequency shift module, by changing a frequency of the electrical local oscillation source, the wide frequency range under low-frequency electrical local oscillation and the down-conversion of a tunable microwave signal are implemented.

Description

technical field [0001] The invention relates to the technical field of microwave photonics, in particular to a microwave photon down-conversion device and a microwave photon down-conversion method. Background technique [0002] With the increasing demand for frequency bands in applications such as wireless communication, satellite communication, and radar detection, the current microwave frequency band resources are becoming more and more tense, prompting microwave communication to gradually develop into high-frequency bands. The traditional microwave mixer down-converts the frequency of the received signal to an intermediate frequency or DC with a lower frequency, thereby reducing the bandwidth requirement of the receiving end, but the microwave mixer suffers from small operating bandwidth, low isolation, large loss, and low conversion efficiency. The impact of the problem has made it increasingly difficult to meet current needs. Microwave photon frequency conversion uses ...

AI Technical Summary

Problems solved by technology

This method uses a mode-locked laser to generate an optical frequency comb, which has problems such as complex system, poor light source stability and poor tuning

In the series or parallel electro-optic modulator method, the radio frequency signal to be converted and the electric local oscillator signal are respectively loaded on two different electro-optic modulators to generate a series of sidebands, and the modulated light sidebands with two adjacent frequencies pass through photoelectric detection. The beating frequency of the device is used to realize down-conversion. Although this method solves the disadvantage of poor tuning in the optical frequency comb heterodyne method, the frequency of the electrical local oscillator source required for high-frequency RF signal processing is relatively high, making the RF signal to be processed Frequency range limited

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