Multiple-input method and apparatus of free-space optical communication

摘要

An approach is provided that uses diversity to compensate fading of free-space optical (FSO) signals propagating through an environment characterized by atmospheric scintillation. One embodiment involves collecting at least one FSO beam, demultiplexing the beam by wavelength into at least two sub-beams, detecting each sub-beam to produce an electrical output therefrom, and recovering a signal using complementary information from at least two of the electrical outputs. Another embodiment involves collecting the FSO beam onto an array of spatially separated sub-apertures, detecting the light entering each sub-aperture to produce an electrical output therefrom, and recovering a signal using complementary information from at least two of the electrical outputs. This second embodiment enables both electronic adaptive processing to coherently integrate across the sub-apertures and in the case of multiple transmit apertures a free space optical Multiple Input Multiple Output (MIMO) system.

主权项

1. A method, comprising:
collecting at least one free space optical beam; directing the beam to a fiber bundle; demultiplexing the beam by wavelength into two or more sub-beams; outputting the two or more sub-beams separated at least by the coherence bandwidth, the two or more sub-beams being associated with complementary information; detecting the two or more sub-beams to produce electrical outputs corresponding to each of the two or more sub-beams and associated with the complementary information; selecting at least two of the electrical outputs based on a strength, an assigned weight or a propagation coefficient of the complementary information associated with the at least two electrical outputs to recover a signal during a time interval; and recovering the signal using the complementary information.