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    TELESCOPE FOR A FREE-SPACE WIRELESS OPTICAL COMMUNICATION SYSTEM
    31.
    发明专利
    TELESCOPE FOR A FREE-SPACE WIRELESS OPTICAL COMMUNICATION SYSTEM 未知

    公开(公告)号：CA2357972A1

    公开(公告)日：2002-04-05

    申请号：CA2357972

    申请日：2001-09-27

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： PRESBY HERMAN MELVIN ,  TYSON JOHN ANTHONY

    IPC: G02B23/02 ,  G02B17/06 ,  G02B27/00 ,  G02B27/18 ,  H01L31/12 ,  H04B10/112 ,  H04B10/10 ,  H04B10/04 ,  H04B10/06

    Abstract: A free-space wireless optical communication system is disclosed that utilizes a telescope design having aspherical mirrors, such as a Richey- Chetrien (RC) telescope. RC telescopes are characterized.by a concave primary mirror and a convex secondary mirror each having a hyperbolic shape. The mirror configuration of the present invention allows the primary and secondary mirrors to be positioned closer together than conventional designs, allowing for a very compact system. The disclosed mirrors can be thin and lightweight, allowing for a lightweight telescope unit. The mirror configuration of the present invention provides a larger focal plane, allowi ng for automatic alignment between a transmitter and receiver with a stationary or fixed mirror design, further contributing to a lower fabrication cost, and can be fabricated with large diameters, allowing the transmission of high beam intensities at eye-safe levels since the energy is spread over a large area. A number of fabrication techniques are disclosed that permit the optical telescopes of the present invention to be fabricated at a reasonable cost that permits such optical telescopes to be deployed in wireless optical communication systems.

    34.
    发明专利
    未知

    公开(公告)号：DE69800016T2

    公开(公告)日：2000-03-23

    申请号：DE69800016

    申请日：1998-04-28

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： MARCUSE DIETRICH ,  PRESBY HERMAN MELVIN

    IPC: G02F1/335

    Abstract: An acousto-optic silica optical circuit switch that selectively routes signals to one of two outputs includes a surface-acoustic-wave source (5) and a coupler waveguide structure formed within silica glass. The waveguide structure includes a single mode input section (100) connected to a multimode section connected to first and second single mode output sections (110,115). The first output section (105) has a structure capable of accepting power from an optical signal propagating in a first transmission mode of the multimode section, and the second output section has a structure capable of accepting power from an optical signal propagating in a second transmission mode in said multimode section. In operation, RF excitation is selectively provided to the SAW source to selectively cause coupling of the first and second transmission modes in the multimode section. As a consequence, an optical signal launched in the input section propagates through the multimode section to the first output section in the first transmission mode of the waveguide structure, or alternatively, such launched optical signal is coupled to the second transmission mode in the multimode section such that its power is transferred to the second transmission mode to propagate into the second output section.

    METHOD AND APPARATUS FOR ALIGNING TELESCOPES WITHIN A FREE-SPACE OPTICAL COMMUNICATION SYSTEM
    35.
    发明专利
    METHOD AND APPARATUS FOR ALIGNING TELESCOPES WITHIN A FREE-SPACE OPTICAL COMMUNICATION SYSTEM 未知

    公开(公告)号：CA2357660C

    公开(公告)日：2006-01-24

    申请号：CA2357660

    申请日：2001-09-24

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： PRESBY HERMAN MELVIN ,  TYSON JOHN ANTHONY

    IPC: H04B10/10 ,  H04B10/04 ,  H04B10/06 ,  H04B10/118 ,  H04B10/22

    Abstract: A free space optical communication system is disclosed whereby a transmit telescope and a receive telescope are aligned such that the point o f maximum power of the received light beam is incident upon the optical fiber located at a specific point on the focal plane of the receive telescope. Suc h incidence is achieved by causing the transmitted beam to diverge by moving the transmit optical fiber to a point in front of the focal plane of the transmit telescope until at least a portion of the beam is incident upon the receive optical fiber. The transmit telescope and/or the receive telescope (or, alternatively, only the respective optical fibers of those telescopes) are then moved such that the point of maximum received power for that degree of divergence is incident upon the receive optical fiber. The transmit optical fiber, in response to received power measurements at the receive telescope, then incrementally moves back toward the focal plane of the transmit telescope thereby reducing the degree of divergence and achieving a greater signal per unit area at the receive telescope. As the divergence is reduced, the position of the either the transmit telescope and/or the receive telesco pe (or, respectively, the optical fibers) is incrementally adjusted to maximize the received power of the received signal which is incident upon the receive optical fiber for each degree of divergence. By monitoring received signal power this iterative process continues until the transmit and receive telescopes are aligned such that the transmitted beam is focused so as to maximize the received power that is incident upon the receive optical fiber.

    METHOD AND APPARATUS FOR CONTROLLING RECEIVED POWER LEVELS WITHIN A FREE-SPACE OPTICAL COMMUNICATION SYSTEM
    39.
    发明专利
    METHOD AND APPARATUS FOR CONTROLLING RECEIVED POWER LEVELS WITHIN A FREE-SPACE OPTICAL COMMUNICATION SYSTEM 未知

    公开(公告)号：CA2357943A1

    公开(公告)日：2002-04-05

    申请号：CA2357943

    申请日：2001-09-28

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： PRESBY HERMAN MELVIN ,  TYSON JOHN ANTHONY

    IPC: H04B10/10 ,  H04B10/118 ,  H04B10/22 ,  H04B10/04 ,  H04B10/06

    Abstract: A free space optical communication system is disclosed whereby the received power at the receive optical fiber is reduced by adjusting the transmitted light beam and the receive optical fiber with respect to each other when a specified power threshold is exceeded so that they intersect not at a point of focus, but at a point of divergence of the transmitted beam. In one embodiment, the transmitted beam may be diverged by moving the transmit optical fiber to a point in front of the focal plane of the transmit telesco pe along the longitudinal axis of that telescope until at least a portion of th e beam is incident upon the receive optical fiber. This causes the transmitted beam to diverge and, accordingly, the cross-sectional area to increase at th e point where it is incident upon the receive telescope. As a result, the cros s- sectional power per unit area of the transmitted beam at the receive telescope is reduced which correspondingly reduces the power that is incident upon the receive optical fiber. In another embodiment, instead of moving the optical fiber at the transmit telescope, the optical fiber located at the focal plane of the receive telescope may be moved to either a point in front of or to a point to the re ar of the focal plane of the receive telescope along the longitudinal axis ofth e receive telescope. Since the maximum possible received power is achieved at the focal point within the focal plane, any movement of the receive optic al fiber away from the focal point along the longitudinal axis of the receive telescope will result in a reduction of the received power.

    METHOD AND APPARATUS FOR COMMUNICATION SIGNAL AUTOTRACKING WITHIN A FREE SPACE OPTICAL COMMUNICATION SYSTEM
    40.
    发明专利
    METHOD AND APPARATUS FOR COMMUNICATION SIGNAL AUTOTRACKING WITHIN A FREE SPACE OPTICAL COMMUNICATION SYSTEM 未知

    公开(公告)号：CA2357918A1

    公开(公告)日：2002-04-05

    申请号：CA2357918

    申请日：2001-09-28

    Applicant: LUCENT TECHNOLOGIES INC

    Inventor： TYSON JOHN ANTHONY ,  PRESBY HERMAN MELVIN ,  AHRENS ROBERT G

    IPC: G02B23/02 ,  G02B17/08 ,  G02B23/12 ,  H04B10/112 ,  H04B10/118 ,  H04B10/10 ,  H04B10/04 ,  H04B10/06

    Abstract: A free space optical communication system is disclosed whereby the signal amplitude incident upon a receive optical fiber of a receive telescop e is varied by dithering either the light beam transmitted by a transmit telescop e or the receive optical fiber when a decrease in received signal amplitude is measured so as to effect the incidence of the maximum transmitted signal amplitude upon the receive optical fiber at the receive focal plane. In one embodiment, the transmit optical fiber is dithered in a pattern, causing the transmitted beam to oscillate in a corresponding pattern. In response, the received signal amplitude of the image on the focal plane of the receive telescope also oscillates in the same pattern. By comparing the phase of the received signal with the phase of the movement of the transmitted beam, the origin of the transmitted beam dithering pattern can be moved until the maximum amplitude of the transmitted beam is incident upon the receive optical fiber. In another embodiment, the receive optical fiber is dithered in a variable pattern to locate the point of maximum received signal amplitude. Using the aforementioned phase comparison technique, the receive optical fiber is moved progressively closer to the point of maximum amplitude of the received signal on the receive focal plane. In cases where atmospheric disturbances alter the path of the transmitted beam, the transmitted beam and the receive optical fiber may both be dithered to achieve coincidence between the point of maximum signal amplitude and the receive optical fiber.

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