Jds Uniphase Corporation

Tellium, Inc.

Other

W John Tomlinson

Krishna Bala

Thomas Ducellier

John K Gamelin

Paul Colbourne

Long Yang

Barrie P Keyworth

Brian Lee Heffner

Robert I MacDonald

Janet L Jackel

Jinxi Shen

Oleg Bouevitch

Yevgeniy Churin

Valentine N Morozov

Charles A Brackett

Jayantilal Patel

Jasvinder Obhi

Jacques Bismuth

David John Danagher

Paul H Beckwith

A wavelength blocker including an input port for launching an input beam of light, first dispersing means for dispersing the input beam of light according to wavelength, an array of independently addressable elements for selectively blocking a portion of the dispersed beam of light, second dispersing means for receiving the passed dispersed beam of light and for producing a single multiplexed beam of light therefrom, and an output port for transmitting a modified output beam of light. The array of independently addressable elements are designed such that the wavelength blocker is capable of blocking a variable number of non-consecutive channels without significantly affecting the unblocked channels.

Wavelength blocker

A dynamic gain flattening filter is provided that offers a smooth spectral response. The filter includes an input/output port for launching a beam of light, a dispersive element for dispersing the beam of light into a plurality of monochromatic sub-beams of light, and discrete array of controllable elements for receiving the plurality of sub-beams of light. The filter is designed such that each sub-beam of light is incident on more than one element of the discrete array for selective attenuation before being recombined by the dispersive element and redirected back to the input/output port. In another embodiment, a beam-folding mirror is provided to direct the attenuated beam to a separate output port.

Dynamic gain flattening filter

A method of controlling a response function of a pixelated dynamic gain controller involving structuring the problem as a set of linear equations that are used to efficiently and accurately determine an initial set of pixel settings and further can be iterated to determine optimum pixel settings for a desired response function. In particular, the gain controller is comprised of an array of individually controllable pixels such as an array of liquid crystals. Adjusting drive conditions to each pixel controls the relative transmission of a narrow band of wavelengths through each pixel. The target response function is achieved by structuring the control conditions as a set of linear equations with which it is possible to accurately determine an initial set of pixel settings. The settings can be iterated to determine an optimum setting for a desired response function or change in response function. Additionally, compensating pixels at the edges of the array are used to compensate for edge effects.

Method of controlling a dynamic gain controller

An optical device for rerouting and modifying an optical signal that is capable of operating as a dynamic gain equalizer (DGE) and/or a configurable optical add/drop multiplexer (COADM) is disclosed. The optical design includes a front-end unit for providing a collimated beam of light, an element having optical power for providing collimating/focusing effects, a diffraction element for providing spatial dispersion, and modifying means which in a preferred embodiment includes one of a MEMS array and a liquid crystal array for reflecting and modifying at least a portion of a beam of light. The modifying means functions as an attenuator when the optical device operates as a DGE and as a switching array when the optical device operates as a COADM. Advantageously, this invention provides a 4-f system wherein a preferred embodiment the element having optical power is a concave reflector for providing a single means for receiving light from the front-end unit, reflecting the received light to the dispersive element, receiving light from the dispersive element, and providing dispersed light to the modifying means. Conveniently and advantageously, this same concave reflector is utilized on a return path, obviating the requirement of matching elements. In one embodiment a single focussing/collimating lens is provided substantially at a focal plane of the element having optical power.

Optical configuration for a dynamic gain equalizer and a configurable add/drop multiplexer

A liquid-crystal switching element relying upon a segmented liquid-crystal polarization modulator, at least one frequency-dispersive grating and one or more polarization-dispersive elements, such as Wollaston prisms, to switch separate wavelength-divided signals among four optical paths. The switching is done complementally between the fibers of each pair, and the same switching is done for the two pairs. According to the invention, all four beams can be processed by a single set of serial optics. The invention is particularly useful as an optical interconnect between two optical fiber communications rings in which each ring includes two counter-rotating fibers. The invention advantageously uses a dielectric thin-film beam splitter for one of the polarization-dispersive elements and a Wollaston prism for the other. The reflective embodiment in which a mirror replaces all the components on the output side can be improved by using two semitransparent electrode layers on the input side separated by a quarter-wavelength of dielectric.

Dual liquid-crystal wavelength-selective optical switch

An optical matrix protection system is described. Optical signals that are cross-connected by a N&times;N matrix switch are routed through alternative protection paths using an optical matrix protection system. The optical matrix protection system includes a N&times;1 optical switch and a 1&times;N optical switch. An input port of the 1&times;N optical switch is coupled to an output port of the N&times;1 optical switch. Input ports of the N&times;1 optical switch are connected to a plurality of 1&times;2 optical switches, which selectively switch input optical signals to either the N&times;N matrix switch or to the N&times;1 optical switch. Output ports of the 1&times;N optical switch are connected to a plurality of 2&times;1 optical switches, which selectively switch optical signals from either the N&times;N matrix switch or laid the 1&times;N optical switch to an output line.

Optical matrix protection system

A protection system for a micro electro-mechanical system (MEMS) cross-bar switch is described. Optical signals that are cross-connected by a N&times;N optical matrix switch are routed through alternative protection paths using protection switch elements. The protection switch elements are incorporated as part of the silicon wafer based fabricated structure that forms the N&times;N optical matrix. The protection switch elements enable the N&times;N optical matrix switch to recover from one or more failures in switch elements of the N&times;N optical matrix using alternative protection paths that have the same path length as the original optical path.

Protection for MEMS cross-bar switch

A reconfigurable multiwavelength network element includes a first demultiplexer unit for demultiplexing a first multiplexed optical signal from a first optical fiber into a first plurality of optical outputs; a second demultiplexer unit for demultiplexing a second multiplexed optical signal from a second optical fiber into a second plurality of optical outputs; a first multiplexer unit having first optical inputs for receiving signals to be multiplexed together; a second multiplexer unit having second optical inputs for receiving signals to be multiplexed together; and a cross-connect unit having first and second portions, the first portion directing signals received from at least a first one of the first plurality of optical outputs and a first one of the second plurality of optical outputs to a first one of the first optical inputs and a first one of the second optical inputs, the second portion directing signals received from at least a second one of the first plurality of optical outputs and a second one of the second plurality of optical outputs to a second one of the first optical inputs and a second one of the second optical inputs.

Reconfigurable multiwavelength network elements

An optical switch particularly usable as a wavelength-division add/drop multiplexer (WADM) in a multi-wavelength communication system. Four multi-wavelength beams optically coupled to the input, output, add, and drop channels are arranged in parallel in a rectangular array and are incident upon a diffraction grating. The grating operating in one direction disperses the beams into their wavelength components and operating in the other direction recombines the wavelength components into a multi-wavelength beam. A lens focuses the components of the beams having a particular wavelength upon one of an array of tiltable micro-mirrors integrated on a silicon substrate. In one position, the mirror for a particular wavelength reflects that wavelength component from the input beam back to the output beam. In a second position, that mirror reflects that wavelength component from the input beam back to the drop beam and reflects that same wavelength component from the add beam back to the output beam. The same optics can be used for a second set of beams which are switched in synchronism with the first set. The array of mirrors can be fabricated to be tiltable to more than two positions so that the input beam can be selectively coupled to either the output beam or one of at least two drop beams while the output beam is correspondingly selectively coupled to either the input beam or one of at least two add beams.

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Princeton, NJ, United States of America

W John Tomlinson