Optical true time delay method and system based on dispersion and frequency spectrum processing

Abstract

The invention provides an optical true time delay method and system based on dispersion and frequency spectrum processing. The optical true time delay method comprises the following steps: a tunable laser carrier is input; a microwave signal is modulated onto the tunable laser carrier to obtain an optical signal; a quadratic-form phase is added to the optical signal for frequency spectrum reshaping so as to obtain the optical signal after the frequency spectrum reshaping; the optical signal after the frequency spectrum reshaping is subjected to the dispersion processing through a dispersion element; the optical signal output by the dispersion element is subjected to photoelectric detection to obtain a microwave signal, wherein wide-range time delay is realized through adjustment of the frequency of the laser carrier, and the time delay range is within 0-1,717ps; fine adjustment of time delay is realized through control over the quadratic-form phase, and the stepping rate of the time delay is 0.67ps. According to the optical true time delay method, the frequency spectrum reshaping is realized in the mode that the quadratic-form phase is added to an optical frequency spectrum, so that fine tuning of the time delay is realized, and the accuracy is improved. Through laser wavelength tuning and the dispersion element, the time delay range of the microwave signal is expanded.

Description

technical field [0001] The invention relates to the technical field of optical signal processing, in particular to an optical true delay method and system based on dispersion and spectrum processing. Background technique [0002] Optical true time delay technology (optical true time delay, OTTD) refers to the use of photonics methods to realize the controllable delay of microwave signals. It has broad application prospects in phased array technology, signal processing technology, and optical network cache. Compared with the electrical method, it has the advantages of low loss, large bandwidth, small size, and anti-electromagnetic interference. The time required for the optical signal to pass through the waveguide can be expressed as: τ=n(ω)l / c, where τ is the delay of the optical signal, n(ω) is the refractive index, and l is the length of the waveguide. Based on the above formula, there are mainly the following methods to achieve optical true delay: (1) Switching optical ...

AI Technical Summary

Problems solved by technology

It can be seen that in the case where the tuning range of the laser is limited, to achieve a large delay, the only way to increase the dispersion of the dispersion device

And this will inevitably increase the delay step and reduce the continuity of delay tuning

[0004] There is a serious problem in the delay technology using dispersion: the microwave power fading caused by dispersion

[0013] Existing technical solutions cannot take into account both delay range and delay fineness

figure 1 The technical solution in can achieve a wide range of delay, but the step is often large, and the transmission bandwidth is also limited

and figure 2 The technical solution in achieves fine tuning of the delay, but the range of delay is limited

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