Ultra-Wideband Direction Finding Using Fiber Optic Transversal Filters

摘要

This report describes a wideband electro-optic direction finding (DF) processor using an array of laser diodes, an array of photodetectors, and a network of fiber optic delay lines. This DF filter offers a potential operational bandwidth in excess of 10 GHz and allows for multiple, simultaneous beam angular responses with peaks that are independent of frequency. Two eight-laser, two-transversal filter laboratory test model DF devices, one using multimode optical fiber and the other single-mode fiber, were constructed. These experimental matched-delay filters are operable in the 200- to 1800- systems' sensitivity, dynamic range, angular resolution, and frequency response. It is concluded from theoretical and experimental results obtained in this investigation that the multitude DF device is slightly superior in performance to the single-mode system due to the higher throughput optical power levels possible with multimode systems. Further, it is concluded that the fiber optics matched-delay filter can be a useful device for ultra-wideband direction finding. (Author)