Lucent Technologies Inc.

Ciena Corporation

At+t Corp.

At&t Bell Laboratories

Henry H Yaffe

Charles H Henry

Leonard G Cohen

Stephen B Alexander

Yuan P Li

Edward J Laskowski

Victor Mizrahi

Jean-Luc Archambault

Andrei Csipkes

Yan Wang

Michele A Milbrodt

Morton I Schwartz

Norman Roger Lampert

Balakrishnan Sridhar

Uziel Koren

Ian A White

Rudolf F Kazarinov

Raymond A Cirelli

Cecilia Y Mak

Dave A Schwarten

Charles Duvall

Steve B Alexander

Yves Pradieu

In accordance with the present invention, optical channels to be demultiplexed are supplied to first and second optical fibers via an optical splitter. Low loss interference filters, for example, coupled to the first and second optical fibers, select respective groups of channels. Each group of channels is next demultiplexed with sub-demultiplexers into individual channels, each of which is then sensed with a corresponding photodetector. Although the optical splitter introduces an optical power loss at the input to the demultiplexer, the interference filters and sub-demultiplexers create little additional loss. As a result, the total power loss associated with the present invention is significantly less than that obtained with a conventional n channel demultiplexer based on a 1&times;n splitter. Accordingly, large numbers of channels, e.g., in excess of forty can be readily demultiplexed and detected.

Dense WDM optical multiplexer and demultiplexer

In accordance with the present invention, optical channels to be demultiplexed are supplied to first and second fibers via an optical splitter. Low loss interference filters, for example, coupled to the first and second optical fibers, select respective groups of channels. Each group of channels is next demultiplexed with sub-demultiplexers into individual channels, each of which is then sensed with a corresponding photodetector. Although the optical splitter introduces an optical power loss at the input to the demutiplexer, the interference filters and sub-demultiplexer create little additional loss. As a result, the total power loss associated with the present invention is significantly less than that obtained with a conventional n channel demultiplexer based on a 1&times;n splitter. Accordingly, large numbers of channels, e. g., in excess of forty can be readily demultiplexed and detected.

The component parts for assembly of a device, such as the passive optical components of an optical amplifier, are automatically selected from among a supply of available component parts. Each component part has a performance parameter such as insertion loss associated therewith. Stored in a database memory are component part data for each component part of the supply of available component parts. The component part data are in a computer readable format and indicative of a type of each part and the performance parameter of each part. To obtain the selection of parts of the device for assembly, the component part data for a plurality of the available component parts is retrieved from the database, and the thus retrieved plurality of component part data are sorted according to at least the performance parameter of each retrieved component part data. At least one component part among the sorted component part data is selected based on a preset parameter. Then, at least one remaining component part among the sorted component part data is identified based at least on the performance parameter of the at least one component part and the performance parameter of the at least one remaining component part.

Method and apparatus for sorting components

The present invention provides an optical monitoring system for a WDM optical communication system. In an exemplary embodiment, the monitoring system includes a wavelength selecting device which receives a WDM optical communication signal comprising plural optical channels and optical noise (e.g., ASE). The wavelength selecting device separately outputs optical signals corresponding to each of the optical channels and at least one optical noise sample taken at a wavelength which is not occupied by one of the optical channels. At least one optical power meter optically communicates with the wavelength selecting device for measuring the optical power of each of the optical channels and the optical noise sample. The optical power meter outputs an electrical signal indicating the strength of a measured optical channel or of the optical noise sample. A data analyzer, such as a microprocessor, receives the electrical signals output by the power meter and calculates the optical noise at the wavelengths of each of the N optical channels based upon the measured noise sample. Using the calculated optical noise values, the data analyzer determines the signal to noise ratio of each optical channel. Advantageously, the technique of the present invention uses a minimum of power measurements to accurately determine the signal-to-noise ratios of the optical channels.

Signal-to-noise monitoring in WDM optical communication systems

A computer system and method provide a CAD tool by which application specific optical integrated circuits may be easily and quickly designed. The computer system has a graphical user interface which provides the designer with an empty canvas upon which the user may place selected icons of any one of a plurality of optical devices. The designer can select from any one of a number of interconnects to place an icon of the selected interconnect between two of the optical devices. The characteristics of each optical device or interconnect may be varied from default settings to a desired group of settings. To verify the operation of a designed circuit, the user simply clicks each icon along an optical path and the computer system provides a spectral analysis of optical power versus wavelength for the defied optical path. The user can also design optical chips by selecting and placing end ports into an optical circuit and can then clump or group the entire optical circuit into a single icon representing the chip. The computer system also provides the designer with the ability to group optical chips together to form wafers. The optical circuits, as well as the chips and wafers, may be designed in any one of several manufacturing standards.

Method and system for designing and analyzing optical application

A computer system and method provide a CAD tool by which a mask for an application specific optical integrated circuit, chip, or wafer may be generated both easily and quickly. The method involves the step of receiving the design for an optical circuit with the circuit design including at least one optical component. Each optical component in the optical circuit is defined by one or more geometric shapes, such as a trapezoid, rectangle, or an arcuate polygon. The method further includes the step of retrieving parameters which define the manufacturing standard by which the optical circuit will be fabricated as well as parameters which define the optical components in the optical circuit. Based on the parameters and the geometric shapes, a plot is generated which forms a mask layout for the optical circuit. The mask layout can then be viewed by a graphical editor whereby a designer can receive visual confirmation that the mask layout accurately portrays the desired optical circuit, chip, or wafer.

Method and system for generating a mask layout of an optical integrated

The present invention provides modular optical amplifier constituents suitable for constructing optical amplifiers of various designs and modular fiber optic cassettes. Each stage of a multiple stage optical amplifier is housed in a separate optical cassette. Optical pump(s) are separately packaged in pump modules to further simplify amplifier design and enhance amplifier manufacturability. In an exemplary embodiment, a modular optical amplifier is constructed comprising a first amplifier housing including a first optical cassette for holding a first amplifier stage. Cassette regions are provided for receiving one or more passive optical components used with the first stage of the optical amplifier. A first length of rare-earth doped optical fiber is retained by cassette retaining projections and optically communicates with a pump interconnection element. A second amplifier housing is provided comprising a second optical cassette for holding a second amplifier stage in a substantially similar manner as the first optical cassette. At least one optical pump is retained in an optical pump housing separate from the first and second optical cassettes for supplying pump energy to the optical amplifier. The cassettes are optionally mounted vertically or adjacent one another on a circuit board. The circuit board may include electrical circuits for monitoring amplifier performance and for passing the monitoring information to a network management system.

Modular optical amplifier and cassette system

An optimized waveguide structure enables the functional integration of various passive optic components on a single substrate. The optimized waveguide structure is characterized by a thicker core layer than used for square core waveguides and a core width that changes according to different functional regions of the optic circuit within which it is incorporated. The height (H) of the waveguide core is determined by the thickness of the core layer defined during the fabrication process and is ideally uniform across the circuit. The width (W) of the core, however, is changed between functional regions by the photo-lithographic mask and the chemical etching during the fabrication process. By way of example, an optimized waveguide structure for a P-doped silica planar waveguide with a .DELTA. approximately 0.6% for wavelength .lambda.=1.2-1.7 .mu.m, has a single uniform height of H=6.7 .mu.m and a width that changes between W=4 .mu.m in a coupler region, W=5.5 .mu.m in a bend region, W=9 .mu.m in a fiber coupling region, and W=10 .mu.m in a phase grating region of a Dragone router. Adiabatic tapers are used as transition regions between regions of different core widths.

Optimized waveguide structure

A connector assembly for coupling an optical fiber to an active optical device has a metal sleeve and an L-shaped alignment block having perpendicularly disposed reference surfaces. A resilient member on the sleeve biases an optical fiber terminating plug against the reference surfaces. The active optical device is attached to a ceramic sub-mount and the sub-mount is placed on one of the reference surfaces. The sub-mount is sized so that an optical port for the active optical device will become aligned with the central axis of the plug. To couple the optical fiber with the active optical device, the plug is slid into contact with the active optical device and is rotated until the fiber is substantially registered with the optical port. The sleeve may have a second resilient member for receiving another plug from the opposite end of the sleeve with a fiber in the other plug being coupled to a second optical port. The active optical device can comprise a variety of devices, such as a laser or an optical modulator with mode field beam expanders.

Fiber and active optical device interconnection assembly

An optical integrated circuit provides multiple power splitting functions and comprises a plurality of optical power splitters networked together. In one embodiment, the optical integrated circuit has two 2.times.2 optical power splitters ganged together such that the circuit simultaneously provides two different 1.times.2 power splitting functions and four different 1.times.3 power splitting functions. In another embodiment, the optical integrated circuit has three 2.times.2 optical power splitters ganged together such that the circuit simultaneously provides two 1.times.2 power splitting functions, four 1.times.3 power splitting functions, and two 1.times.4 power splitting functions. Since each integrated circuit provides more than one power splitting function, the integrated circuit is more versatile than a single power splitter. The integrated circuit may also present a lower cost in comparison to a circuit formed with discrete elements since additional power splitters can be placed on a single substrate for only a nominal increase in cost. The integrated circuit further reduces the time needed to couple fibers to their respective power splitters since multiple fibers in a fiber ribbon array can be simultaneously coupled to the ports of the optical integrated circuit.

Multi-purpose optical integrated circuit

In accordance with the invention, a new type of monolithic optical waveguide filter comprises a chain of optical couplers of different effective lengths linked by differential delays of different lengths. The transfer of the chain of couplers and delays is the sum of contributions from all possible optical paths, each contribution forming a term in a Fourier series whose sum forms the optical output. A desired frequency response is obtained by optimizing the lengths of the couplers and the delay paths so that the Fourier series best approximates the desired response. The filter is advantageously optimized so that it is insensitive to uncontrolled fabrication errors and is short in length. The wavelength dependence of practical waveguide properties is advantageously incorporated in the optimization. Consequently, the filter is highly manufacturable by mass production. Such filters have been shown to meet the requirements for separating the 1.3 and 1.551 .mu.m telecommunications channels and for flattening the gain of Er amplifiers.

Monolithic optical waveguide filters based on Fourier expansion

An optical integrated circuit provides a 1.times.2 power splitting function for a communication system and additionally provides at least one type of upgrade capability for the system. The upgrade capability may be remote optical time domain reflectometry (OTDR) testing at an out-of-band wavelength. The OTDR testing is performed around a power splitter whereby a fault may be precisely located on an output line past the power splitter. Other upgrade capabilities that an optical integrated circuit may provide are the ability to add optical network units (ONUs) to the communication at a later time or to increase the bandwidth without requiring any new cables between a central office and the optical circuit. The optical integrated circuits can provide these upgraded capabilities with a higher reliability than circuits which are manufactured with discrete components and at a lower cost.

Optical integrated circuits and methods

A waveguide Bragg reflector is made by forming periodic grooves in either the undercladding or the core, applying a high index coating on the grooved surface and selectively removing the coating from the horizontal surfaces while leaving the coating on the vertical surfaces. The waveguide is then completed.

Method for making Bragg reflectors for waveguides

An optical communication network includes a novel, passive optical component. This component combines the function of a splitter with the function of a wavelength-division multiplexer. These functions are performed in distinct wavelength bands. In one embodiment, the inventive component is made using silicon optical bench technology.

Optical network comprising a compact wavelength-dividing component

In accordance with the invention the birefringence induced by compressive strain in silica waveguides on silicon substrates is compensated with a high index patch--such as silicon nitride--placed adjacent the core. The patch is disposed sufficiently close to the core to optically couple with the transmitted optical mode. The patch is preferably wider than the core to intersect the exponential tail of the transmitted optical mode. Such a high index patch preferentially couples TE polarization modes. By choosing an appropriate length for the patch, both strain and bend birefringence can be compensated.

Growing community of inventors

Dunwoody, GA, United States of America

Henry H Yaffe