ABSTRACT
This chapter describes the fundamental principles of Fourier optics and its implementation in guided wave structures using either fiber or integrated planar or channel waveguide forms. The applications of optical discrete Fourier transform (DFT) and inverse DFT (IDFT) as well as discrete wavelet transformation is presented in advanced optical transmission systems operating at speeds on the order of terabits. Fourier transform offers the orthogonality needed for such an operation due to the summation of the harmonic terms of sine and cosine terms. Fourier optics offers an excellent technique for processing optical signals. Modern technology on planar light wave circuits using silica on silicon offers such an implementation for an integrated Fourier optical transformer. In optical processing the frequency down sampling components of the Fourier transform are realized by using a delay path whose propagation time is equivalent to the inverse of the frequency component.
