公开(公告)号：CA2357927C

公开(公告)日：2006-05-02

申请号：CA2357927

申请日：2001-09-27

Applicant: LUCENT TECHNOLOGIES INC

Inventor： TYSON JOHN ANTHONY ,  PRESBY HERMAN M

IPC: G02B17/00 ,  H04B10/10 ,  H04B10/04 ,  H04B10/06 ,  H04B10/118 ,  H04B10/22

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 disclosed mirror configuration provides a larger focal plane that allows for automatic alignment between a transmitter and receiver with a stationary or fixed mirror design, further contributing to a lower fabrication cost. Among other benefits, the larger focal plane permits an n x n fiber array to be positioned in the focal plane of the RC optical telescope, thereby enabling point-to- multipoint communications with a single optical telescope. Each fiber in the n x n fiber array of a transmitting telescope can be focused on a different receiving telescope in a wireless optical communication system. In this manner, each fiber in the n x n fiber array sends optical energy over a distinct path to address a given receiving telescope Likewise, for a multipoint-to-point communication system, an n x n fiber arr ay can be positioned in the focal plane 330 of the RC optical receiving telescope, wit h each fiber in the n x n fiber array receiving optical energy over a distinct path from a give transmitting telescope. A number of fabrication techniques are also disclose d 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.

公开(公告)号：CA2357918C

公开(公告)日：2005-08-09

申请号：CA2357918

申请日：2001-09-28

Applicant: LUCENT TECHNOLOGIES INC

Inventor： PRESBY HERMAN MELVIN ,  TYSON JOHN ANTHONY ,  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.

公开(公告)号：CA2382635A1

公开(公告)日：2002-12-29

申请号：CA2382635

申请日：2002-04-19

Applicant: LUCENT TECHNOLOGIES INC

Inventor： TYSON JOHN ANTHONY ,  PRESBY HERMAN MELVIN

IPC: G02B23/02 ,  G02B26/08 ,  H04B10/02 ,  H04B10/10 ,  H04B10/118 ,  H04B10/18 ,  H04B10/22

Abstract: A free space optical communication system is disclosed whereby the optics of a transmit telescope are manipulated using adaptive optics to precompensate for wave front distortion of a light beam transmitted by a transmit telescope. Wave front distortion is manifested at the receive telescope as a change in at least one characteristic of the image of the received signal such as, for example, a reduction in the amplitude of the received signal. A mirror of the transmit telescope is deformed in such a wa y as to reduce the wave front distortion and correspondingly increase the resulting amplitude of the received signal.

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.

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.

公开(公告)号：CA2383022A1

公开(公告)日：2002-12-29

申请号：CA2383022

申请日：2002-04-22

Applicant: LUCENT TECHNOLOGIES INC

Inventor： TYSON JOHN ANTHONY ,  PRESBY HERMAN MELVIN

IPC: G02B26/08 ,  G02B17/00 ,  H04B10/10 ,  H04B10/118 ,  H04B10/22

Abstract: A free space optical communication system is disclosed whereby the optics of a receive telescope are manipulated using adaptive optics to compensate for wave front distortion of a light beam transmitted by a transm it telescope. Wave front distortion is manifested at the receive telescope as a deviation from the normal, orthogonal orientation of the wave front of the transmitted light beam relative to its line of travel. This deviation may be detected, for example, by a wave front sensor, such as a Shack-Hartman senso r, which identifies the slope, or beam tilt, of discrete sections of the transmitted beam. The optics of the receive telescope can then be deformed in such a way as to cancel the wave front distortion and correspondingly reduce the resulting distortion of the received signal.

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.

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.

公开(公告)号：DE60134289D1

公开(公告)日：2008-07-17

申请号：DE60134289

申请日：2001-02-19

Applicant: LUCENT TECHNOLOGIES INC

Inventor： AHRENS ROBERT GEORGE ,  PRESBY HERMAN MELVIN ,  TOURGEE GEORGE E ,  TYSON JOHN ANTHONY

IPC: G02B26/08 ,  H04B10/10 ,  G02B6/04 ,  H04B10/118 ,  H04B10/22

Abstract: A method and apparatus are disclosed for aligning and maintaining the alignment of the transmitting unit and the receiving unit in an optical wireless communication system. The receiving unit includes an optical bundle positioned at the focal point of an objective optic element. The optical bundle is comprised of an array of optical fibers, arranged surrounding the receiving fiber. The receiving unit also includes a number of detectors that measure the optical signal strength on a corresponding fiber in the optical bundle. The array of fibers is used to detect the location of the received signal relative to the receiving optical fiber and to provide feedback to adjust the orientation of the optical bundle to optimize the received signal strength. When misalignment occurs between the received signal and the receiving fiber, some of the incident received signal will be captured by one or more of the outer optical fibers. The amplitude of each of the generated signals are then compared to each other, thereby giving a direction in which to drive the optical bundle back into alignment with the received signal. The present invention provides automatic tracking using the information-carrying optical signal, without the need for a separate laser.

公开(公告)号：CA2395797C

公开(公告)日：2006-08-29

申请号：CA2395797

申请日：2002-07-26

Applicant: LUCENT TECHNOLOGIES INC

Inventor： TYSON JOHN ANTHONY ,  KURCZYNSKI PETER

IPC: G02B5/08 ,  G02B5/10 ,  G02B26/06 ,  G02B26/08

Abstract: An adaptive optics system is disclosed whereby at least one mirror in t he system is manipulated using electrostatic force to selectively attract or repel a portion of the mirror to or from a particular electrode, respectively. This attraction or repulsion is accomplished by mechanically coupling a bound charge layer o f dielectric material to at least one surface of the mirror and then placing a voltage across an electrode in an array of electrodes positioned near that mirror. T he charge in the dielectric material combined with a suitable electric field makes it possible to attract portions of the mirror in one instant and then, by changing the sign on the voltage placed across the electrode, to repel those same portion s in the next instant.