应用于SAL中的超宽带线性啁啾光波发射源的研究

项目名称： 应用于SAL中的超宽带线性啁啾光波发射源的研究

项目编号： No.61471256

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 杨天新

作者单位： 天津大学

项目金额： 81万元

中文摘要： 综合孔径激光雷达(SAL)在航道维度上的分辨率可以突破衍射极限，但遗憾的是在垂直维度的距离分辨率无法靠综合孔径来提高。当使用宽带线性啁啾连续光波成像时，距离分辨率只与线性啁啾光波的扫频宽度有关，1mm的距离分辨率需要扫频宽度不能低于150GHz。如果本项目研制的超宽带（200GHz）线性啁啾光波发生器能作为SAL的光源，就可以充分发挥SAL本身在航道维度上的分辨率优势，构成一个分辨率为1mm×1mm的远距离二维高清晰度成像系统。该系统的二维成像分辨率不受孔径的限制，可以大大减小设备的体积和重量，是传统光学成像系统不能取代的。本项目拟通过对单一波长激光器的连续输出光进行腔外单边带调制，产生多个波长，并分别对每个波长再进行连续线性啁啾调制，最后再将各个线性啁啾的光波汇接成一个在200GHz范围内线性啁啾的光波。只有这样的光源，才能充分发挥SAL的优势，构成一个不可替代的二维高清晰度成像系统。

中文关键词： 光外调制；宽带线性啁啾光波；高距离分辨率；激光雷达发射源；综合孔径雷达

英文摘要： Synthetic Aperture Ladar (SAL) is a technique which uses signal processing to improve the resolution beyond the limitation of physical antenna aperture. It has been shown that the diffraction limit is no longer a limitation for 1D-imaging alone the direction of the flight track in a synthesis aperature ladar system, however, for 2D-imaging the range resolution cannot be improved by the technique of SAL. The range resolution is determined by the swept frequency range of the linearly chirped continuous light waves in a frequency modulation continuous wave (FM/CW) SAL system. For example, for the imaging with 1mm resolution, it needs the swept frequency range of more than 150 GHz. In this project a system which can generate a linearly chirped CW light waves with a super broadwide band of 200 GHz is going to be built up as a light source in a high definition SAL system with 2D imaging resolutions of 1mm × 1mm. The weight and volume of this kind of SAL systems can be reduced significantly comparing to traditional optical imaging systems with the same 2D resolutions, and also it can be replaced by no one at all. A new method of generation of linearly chirped continuous light waves is proposed here in which an optical modulator is used to generate a set of multi-wavelenght CW lights at first. Then each wavelength wave is seperated from the set by optical switches and an interleaver in order to let each of them go through another optical modulator one by one which is driven by a linearly chirped electrical signals. The outputs from the later optical modulator are combined together without any gap in time domain to form a super broadband linearly chirped lightwave in 200 GHz as the final output of the whole system. Only can the SAL system with the light soure like the system built in this project be recognized as an unreplacable 2D high definition imaging system.

英文关键词： Optical External Modulation;Ultra-broad-span Linearly Chirped Lightwaves;High Range Resolution;Emitters for the Ladar;Synthesis Aperture Radar