Asymmetrical laser communication transceiver configuration
First Claim
Patent Images
1. A method for transmitting optical signals through free space, comprising:
- providing a transmit aperture;
determining an inner scale in an atmosphere near the transmit aperture; and
emitting a single broad, divergent and collimated beam generated by a laser and comprising a modulated communication, wherein the beam has a diameter at the transmit aperture that is less than the determined inner scale near the transmit aperture and within the Rayleigh range, and wherein a divergence angle of the beam is selected so that it exceeds a determined turbulence induced beam deviation at a predetermined distance to a receiver.
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Abstract
The present invention is directed to a laser communication transmitter and receiver for wireless optical communication. The laser communication transmitter uses a small diameter so correspondingly divergent beam to provide improved bit error rates. A laser communication receiver includes a diffractive optical element to permit detectors at different spatial locations to detect different wavelengths of the optical signal. An immersion lens may be employed to focus the optical signal to a spot size smaller than the photoactive area of the detector.
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Citations
41 Claims
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1. A method for transmitting optical signals through free space, comprising:
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providing a transmit aperture; determining an inner scale in an atmosphere near the transmit aperture; and emitting a single broad, divergent and collimated beam generated by a laser and comprising a modulated communication, wherein the beam has a diameter at the transmit aperture that is less than the determined inner scale near the transmit aperture and within the Rayleigh range, and wherein a divergence angle of the beam is selected so that it exceeds a determined turbulence induced beam deviation at a predetermined distance to a receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An optical transmission apparatus, comprising:
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a radiation source comprising a laser for emitting a collimated beam of radiation through free space; a modulator in communication with the radiation source for modulating the beam with information; a transmit aperture, wherein the transmit aperture has a size sufficient to output a maximum beam diameter that is less than a determined inner scale of an air current at or near the transmit aperture, and wherein the beam of radiation has a divergence angle that exceeds a determined turbulence induced beam deviation at a receiver. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An optical transmission apparatus, comprising:
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a laser radiation source; a modulator in communication with the radiation source for modulating a beam output by the radiation source with information; a transmit aperture, wherein the transmit aperture causes the beam to be divergent wherein a divergence angle of the single beam is at least about 20 μ
rad, and wherein the diameter of the single beam at the transmit aperture is less than an inner scale of an air current at or near the transmit aperture. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for designing an optical transmitter, comprising:
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providing an optical transmitter capable of emitting a laser beam; determining an inner scale at a proposed location for a transmit aperture; determining a worst case atmospheric induced deviation for the laser beam; selecting a transmit aperture size sufficient to output a maximum beam diameter that is less than the inner scale; selecting an optical wavelength, wherein said selected wavelength and said beam diameter resulted in an angle of divergence for the laser beam that is greater than about 50 mrad. - View Dependent Claims (36, 37, 38, 39, 40, 41)
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Specification