Lucent Technologies Inc.

University of California

Other

John Anthony Tyson

Herman M Presby

Peter Kurczynski

David James Thomson

Robert George Ahrens

Gerald Edward Tourgee

Joshua Simon Bloom

Harold M Dyson

A spatially resolved spectral device comprising a dispersive array to receive an incident light comprising a principal ray. The dispersive array comprising a plurality of dichroic layers, each of the plurality of dichroic layers disposed in a path of a direction of the principal ray. Each of the plurality of dichroic layers configured to at least one of reflect or transmit a different wavelength range of the incident light. The device further comprising a detection array operatively coupled with the dispersive array. The detection array comprising a photosensitive component including a plurality of detection pixels, each of the plurality of detection pixels having a light-receiving surface disposed parallel to the direction of the principal ray to detect a respective one of the different wavelength ranges of incident light reflected from a corresponding one of the plurality of dichroic layers.

Spatially resolved spectral-imaging device

A membrane receives an incident energy signal at a first surface of the membrane. An actuating electrode, located adjacent to the membrane on a side opposite the first surface, applies an actuating pressure to the membrane if an actuating potential is applied between the actuating electrode and the membrane. A restoring electrode, located adjacent to the first surface of the membrane, applies a restoring pressure to the membrane if a restoring potential is applied between the restoring electrode and the membrane. The restoring electrode has an outer surface defining an aperture that enables the incident energy signal to pass, for example, without significant obstruction and without significant attenuation, through the restoring electrode to impinge upon the membrane, and the length of the restoring electrode is at least as great as the smallest width of the aperture.

Electrostatic control of a membrane for adaptive optics and the like

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.

Method and apparatus for automatic tracking of an optical signal in a wireless optical communication system

A free space optical communication system is disclosed whereby a transmit telescope and a receive telescope are aligned such that the point of 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. Such 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 telescope (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 aligning telescopes within a free-space optical communication system

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/or the receive optical fiber with respect to each other when a specified power threshold is exceeded. This reduction in received power is achieved by either increasing the cross section of the transmitted beam relative to the receive telescope or, alternatively, moving the receive optical fiber and thereby enlarge the cross section of the received beam incident upon the receive optical fiber.

Method and apparatus for controlling received power levels within a free space optical communication system

An adaptive optics system is disclosed whereby at least one mirror in the 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 of 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. The 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 portions in the next instant.

Method and apparatus for the correction of optical signal wave front distortion using adaptive optics

A free-space wireless optical communication system is disclosed that utilizes a telescope design having aspherical mirrors, such as a Ritchey-Chretien (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&times;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&times;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&times;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&times;n fiber array can be positioned in the focl plane 330 of the RC optical receiving telescope, with each fiber in the n&times;n fiber array receiving optical energy over a distinct path from a given transmitting telescope. A number of fabrication techniques are also 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.

Point-to-multipoint free-space wireless optical communication system

A method and system for reducing the effects of atmospheric ducting on wireless transmissions, wherein a wireless communication system is comprised of a plurality of base stations having antennas, each base station having a beacon signal transmitter and a beacon signal receiver. Each beacon signal transmitter is configured to transmit a wireless beacon signal to be received by the beacon signal receiver at other, preferably every other, base stations. For each wireless beacon signal, a time delay and a propagation loss is measured. Each measured time delay and propagation loss is compared to an expected time delay and an expected propagation loss corresponding to the wireless beacon signal. The results of the comparison are processed so as to determine a location of atmospheric ducts in the region serviced by the wireless system. Once an atmospheric duct has been located, the antennas of the base stations in the wireless system are arranged so as minimize the transmission of the wireless beacon signals through the duct location.

Growing community of inventors

Pottersville, NJ, United States of America

John Anthony Tyson