Abstract: An amplitude modulation modulated acoustic wave is coupled to a selected region along the length of an optical fiber waveguide transmitting an optical beam to modulate at least one transmission characteristic of the waveguide in the selected region by the amplitude modulation of the modulated acoustic wave to impart the amplitude modulation of the modulated acoustic wave to the optical beam.

Abstract: The dispersion effects in an optical fiber transmission line are equalized by producing a predetermined delay characteristic for each wavelength of an optical beam having a finite bandwidth which is the inverse of a given delay characteristic for each optical wavelength propagated through the transmission line. This is accomplished by launching shorter wavelength components of the optical beam at low angles with respect to the axis of the transmission line into the transmission line and launching longer wavelength components at high angles with respect to the axis of the transmission line into the transmission line. Two arrangements are disclosed to accomplish the above-mentioned launching technique. One arrangement includes a time of flight dependent annularly ruled transmission grating and the other arrangement includes passing a time of flight dependent moving acoustic wave through the optical beam.

Abstract: The communication system includes a holographic system to provide a plurality of spatially multiplexed optical beams each modulated by a different one of a plurality of binary intelligence signals. The plurality of modulated spatially multiplexed optical beams are coherently transmitted on an optical waveguide to a hologram and an array of photosensors to recover each of the intelligence signals. The waveguide may be an optical fiber of the parabolic index type to coherently transmit all of the plurality of modulated spatially multiplexed optical beams, or a plurality of single mode step index optical fibers each coherently transmitting a different one of the plurality of modulated spatially multiplexed optical beams.