Abstract: 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×n splitter. Accordingly, large numbers of channels, e.g., in excess of forty can be readily demultiplexed and detected.

Abstract: Integrated and stand-alone methods and apparatus for adaptively compensating for DGD, SOPMD, and CD in optical communication networks are provided. One apparatus includes at least three optical compensators that are optically coupled together in series and a feedback controller. Each compensator includes a variable optical controller that is optically coupled in series to a birefringent element. An optical communication network is also provided that at least includes an optical transmission line, at least two network terminals, and at least one static compensation module. At least one terminal includes an optical demultiplexer that is coupled to that element, a plurality of &lgr;-compensators, and, optionally, a static optical dispersion compensation element.

Abstract: 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×n splitter. Accordingly, large numbers of channels, e.g., in excess of forty can be readily demultiplexed and detected.

Abstract: 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×n splitter. Accordingly, large numbers of channels, e. g., in excess of forty can be readily demultiplexed and detected.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.