TIME DELAY BEAM FORMATION

摘要

Optical systems are disclosed which are capable of generating and rapidly changing time delays of electrical signals for true time delay beam formation and beam steering and for signal processing applications. The systems utilize an interferometer configuration. A first optical modulator (12) in a first leg of the interferometer (14) is used to modulate coherent light with the signal to be delayed. In a second leg of the interferometer (26), a second optical modulator (28) provides beam steering to a prism stack (30), which produces a set of plane reference waves having a range of orientations required to generate a desired range of time delays. Preferably the optical modulators are acousto optic Bragg cells (12, 28). Alternatively, a stack of lens pairs of diffractive optical elements or a holographic optic element may be used in place of the prism stack. The modulated optical signal from the first leg interferes on an array of photodiodes with the reference waves from the second leg. The resulting electrical signals out of the photodiodes (20) are delayed replicas of the signals driving the optical modulator in the first leg.