Lucent Technologies Inc.

Other

Mujibun Nisa Khan

Jane E Zucker

Rene Henri Monnard

David John DiGiovanni

Bernard Raymond Eichenbaum

Concepts for increasing brightness and uniformity and providing dimming for LED-illuminated signs and display are disclosed. Substantial increase in brightness is achieved via reducing the distance between LED modules and the sign or display they illuminate by placing the LEDs on a raised grid platform constructed with a plurality of intersecting plates. Whenever two plates intersect, a 'grid-node' is formed, creating a plurality of intersections and grid nodes in a two-dimensional array. On each grid-node, two distinct and electrically isolated LED sub-modules are placed. By connecting all LED sub-modules parallel to one dimension (e.g., X-axis) in one series, and all LED sub-modules parallel to the other dimension (e.g., Y-axis) in another series, two electrically isolated LED series are created. Lighting up both series provide maximum brightness and good uniformity; lighting up only one series allows dimming for illuminated signs or displays without any drive current adjustment.

Efficient, uniform, and dimmable sign or display illumination methods using overlapped LED modules on a raised grid platform

An LED replacement-lamp design concept comprising tapered waveguides to provide uniform and broad light distribution is disclosed. Currently, most LED-based replacement lamps for tubular fluorescent lamps place discrete surface-mount LEDs directly on a cylindrical base, which produce wasteful, non-uniform and directional illumination unsuitable for large space and high-ceiling applications. An LED lamp design, proposed as a tubular lamp replacement, comprises of a plurality of discrete LEDs mounted on a common substrate, where all light from each LED is immediately guided and broadened through a tapered waveguide long enough to seamlessly terminate at the lamp's semi-circularly curved cover surface. Many such LED-waveguide assemblies can fill the entire curved cover with diffused and uniform light distribution, resulting in illumination over broad angular ranges. The proposed lamp has a 'D' shaped cross-section wherein the lamp's flat side is used as a heat-sink base to be placed against the ceiling or some blocking surface.

Light distribution using tapered waveguides in LED-based tubular lamps as replacements of linear fluorescent lamps

Dual concentric core fiber is used for optical communication. Inbound messages lying in a first wavelength channel are received from a terminal portion of the fiber, and outbound messages lying in a second such channel are injected into the terminal portion. The optical fiber has at least one annular portion surrounding a central core portion. The inbound messages are received from the annular portion, and the outbound messages are injected into the central core portion. Alternatively, the inbound messages are received from the central core portion, and the outbound messages are injected into the annular portion.

Method and apparatus for bidirectional communication over a single optical fiber

Changing the index in the two output branches of a Y-branch optical waveguide in opposite directions, in amounts which are controlled by electrical signals applied to the branches, is used to control the chirp of the signal outputted from the Y-branch optical waveguide. In this manner, predetermined amount of chirp can be add to or subtract from an input signal to the Y-branch optical waveguide. The Y-branch optical waveguide can be fabricated using Group II-VI, Group III-V or Group IV material systems or using an insulating material, such as lithium niobate. The output branches of a semiconductor implemented Y-branch optical waveguide can be fabricated to each include a multiple quantum well for controlling the refractive index of that branch in response to an electrical signal.

Adiabatic Y-branch waveguide having controllable chirp

A method for determining waveguide facet reflectivity from the electric field propagated from an optical fiber into an optical waveguide. The method determines the electric field propagated from the optical fiber into the optical waveguide by combining field terms resulting from multiple reflections occurring at an endface of the optical fiber and an input facet of the optical waveguide; determines the amount of optical field transmitted into the waveguide as a function of gap distance between the optical fiber and the waveguide; determines the optical power transmitted into the waveguide from the amount of field transmitted into the waveguide; and determines the waveguide facet reflectivity from the determined amount of optical power transmitted into the waveguide.

Method for determining waveguide facet reflectivity

Methods of using an adiabatic Y-branch digital optical modulator provide a substantially chirp-free modulator by changing the refractive index of only a first output branch of the modulator in response to a modulating signal. A second output branch of the modulator, where no refractive index change is induced, is used as the modulator output. The frequency chirp in this Y-branch modulator is negligible because the modulator output waveguide branch experiences little or no refractive index change and, therefore, little or no phase shift in operation. Substantially all of the phase shift occurs in the waveguide branch where the refractive index change is induced. According to a further embodiment, one or both of the output branches are comprised of one or more tapered waveguide sections.

Adiabatic Y-branch modulator with negligible chirp

An optical waveguide for use in an optoelectronic integrated circuit and the associated method of manufacturing such a waveguide. The waveguide is formed by the successive layering of varied waveguide materials on a III-V semiconductor substrate, thereby producing a slab waveguide. The various layers within the slab waveguide are relatively thick, thereby producing a slab waveguide that is sized to be more compatible with an optical fiber and therefore more readily coupled to an optical fiber. The larger slab waveguide structure broadens the fundamental mode of the optical signal. However, multiple modes are also produced in the thicker slab waveguide that include higher order modes. A ridge structure is etched into the slab waveguide, wherein the width and height of the ridge structure are selected to impose lateral confinements on the higher order slab modes. The result is a waveguide that has a broadened fundamental mode yet is essentially single-mode. The resulting broadened fundamental mode is closer in symmetry to the mode of standard optical fibers, thereby enabling the waveguide to be more efficiently coupled to an optical fiber.

Single-mode waveguide structure for optoelectronic integrated circuits

An optical switch array in an M.times.N configuration has a set of M input digital optical Y-branches; a set of N output digital optical Y-branch; and at least one S-bend interconnect waveguide connecting at least one input digital optical Y-branch to at least one output digital optical Y-branch, with the S-bend interconnect waveguide being adiabatically tapered for providing adiabatic modal evolution between the at least one input and output digital optical Y-branches. Each of the set of N output digital optical Y-branches has an associated branch separation point; and an output port of the at least one tapered S-bend interconnect waveguide is connected substantially adjacent to a respective branch separation point of a respective one of the set of N output digital optical Y-branch. Compact digital optical switch arrays can be fabricated using such adiabatically tapered S-bend interconnects to eliminate the overlap sections of intermediate digital optical switch elements of the digital optical switch array, and thus to reduce the overall length of the digital optical switch array for providing improved propagation characteristics.

Adiabatic tapered S-bends for compact digital switch arrays

An optical switch provides improved high speed digital optical switching with a compact and fabrication tolerant configuration, and includes a first waveguide portion, a plurality of intermediate waveguide portions connected to the first portion, with each intermediate portion associated with a first angle .theta..sub.1 where the first angle .theta..sub.1 is less than about 2.0.degree.; and a plurality of branch waveguide portions, with each branch waveguide portion connected to a respective intermediate waveguide portion and associated with a second angle .theta..sub.2 where the second angle .theta..sub.2 is less than .theta..sub.1 and is less than about 0.3.degree..

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Holmdel, NJ, United States of America

Mujibun Nisa Khan