AN OPTICALLY DRIVEN PHASED-ARRAY ANTENNA UTILIZING HETERODYNE TECHNIQUES

A novel optically driven phased array antenna system is proposed. The system utilizes heterodyne techniques to generate the microwave carrie r frequency and phases. The heterodyning at each antenna element requi res three injection locked lasers. The microwave carrier frequency is determined by the order of the modulated sideband used in the injectio n locking scheme. A design is also presented for an integrated optical fast Fourier transform. This device can perform the necessary phase p rocessing for both beam steering and detection of arrival angle. The r ecent knowledge of the noise properties of injection locked semiconduc tor lasers is applied to the proposed antenna system. The effect of no ise on the gain, signal-to-noise ratio, and the bandwidth of the anten na system is examined. It is also shown that the performance degradati on of the system, due to the noise in the lasers, is minimal, and ther efore the bandwidth promise of optical drive could well be achieved wi th the use of heterodyne laser locking techniques.