Abstract: A WDM ring transmission system is provided whereby each optical signal is first dropped from the ring, supplied to an amplifier, and then input to an optical receiver. Typically, a filtering element is also provided either prior to or after the amplifier. The amplifier increases the power of the transmitted optical signal so that the optical signals can be transmitted over greater distances, and the filtering element minimizes any adjacent channel cross-talk light fed to the receiver. Moreover, since the amplifier only amplifies the dropped channel, excessive noise accumulation due to non-uniform spectral gain can be avoided. In addition, channels can be arbitrarily assigned to add/drop elements along the ring.

Abstract: An optical device for modulating optical signals in a wavelength division multiplexed communication system. The device includes a plurality of phase modulators. Each of the phase modulators is configured to provide an associated phase modulated optical signal. Each of a plurality of optical filters receives an associated one of the optical signals and is configured to amplitude modulate the optical signal as an optical filter output signal. The optical filter output signals may be combined onto an aggregate path to a receiver including receiver optical filters for selecting the transmitted channels.

Abstract: The present invention provides a wavelength division multiplexed optical communication system with dynamically stabilized wavelength selectors. To accurately correlate the wavelength of a wavelength selector to the wavelength emitted by an optical transmission source, the present invention uses an optical detector and feedback loop to optimize the wavelength of an optical selection element in accordance with a wavelength of an incident optical channel. In one embodiment, the optical selection element is a Bragg grating associated with a grating wavelength controller, such as a temperature regulator or strain tuning system, to adjust the wavelength band of maximum reflectivity of the grating. The feedback loop communicates with the optical detector and the wavelength controller to modify the grating's reflection wavelength band in accordance with the wavelength of an incident optical channel.

Abstract: Consistent with the present invention, an optical fiber management tool is provided which is attachable to a component board or module. The tool has curved or arcuate portions defining a passage for accommodating an optical fiber, and securing the fiber at a bend radius which is greater than the minimum bend radius of the fiber. The tool further has a handle so that the component board can be readily inserted into or removed from a shelf without breaking the fiber.

Abstract: An optical add/drop multiplexer (OADM) is provided wherein input optical channels are supplied on first and second optical fibers, e.g. via an optical splitter. Low loss interference filters, for example, coupled to the first and second optical fibers, select respective groups or bands of channels. Selected groups of channels to be dropped by the OADM may be demultiplexed with sub-demultiplexers into individual channels. Groups of express channels are supplied to associated filters or gratings to ensure that the channel groups selected from the first and second optical fibers to do not contain undesired channels. Channels to be added by the OADM are multiplexed with sub-multiplexers into channel groups corresponding to the dropped channel groups. The added channel groups and the express channel groups are combined on a single output fiber.

Abstract: Consistent with the present invention, a dispersion compensation module is provided which comprises a housing accommodating one or more spools of DCF. Each spool is provided in a respective package, which can be slidably inserted into or removed from the housing along a track provided within the housing. “Jumpers” or relatively short pieces of fiber can be used to interconnect the spools through adapters external to the packages. As a result, spools of DCF can be readily coupled to one another to provide a desired amount of dispersion compensation. Moreover, the adapters are geometrically configured so that connections can be made to the spools without excessively bending fiber interconnecting the DCF and the DCF itself, while permitting the module to conform to fiber optic packaging standards.

Abstract: An optical switch is described having a plurality of optical input ports, and a plurality of optical output ports. A plurality of mirrors are further included, each of which being configured to direct at least a portion of an optical signal supplied to one of the plurality of optical input ports to a corresponding one of the plurality of optical output ports, such that an intensity associated with each of said plurality of optical signals output from the optical switch is substantially the same.

Abstract: An optical device for minimizing channel drift in a wavelength division multiplexed communication system. The device includes a laser source providing an output signal including a plurality of optical channels. The output signal from the laser is received by a plurality of modulators. Each of the modulators is configured to provide an associated modulated optical signal. Each of a plurality of optical filters receives an associated one of the modulated optical signals and is configured to select an associated optical channel from the modulated optical signals. The optical filter output signals may be combined onto an aggregate path to a receiver including receiver optical filters for selecting the transmitted channels.

Abstract: A WDM ring transmission system is provided having two hubs. Identical groups of optical signals for transmission along the ring are input to both hubs, but one of the hubs includes optical switches for selectively passing one of the groups of optical signals to the WDM ring. Accordingly, if a fault occurs in one of the network-hub connections or one of the hubs becomes defective, the switches couple optical signals from the operational hub to the WDM ring. In addition, optical signals emitted by nodes coupled to the WDM ring are output from both hubs, thereby insuring that signals can be output from, and input to, the ring even if one of the hubs fails.

Abstract: An optical amplifier including shared pumps sources. Outputs from a plurality amplifier pump sources are combined and then divided before being injected into one or more amplifying fiber segments. By sharing pumps, signal loss is avoided in the event of pump failure.

Abstract: A dual-band optical filter is disclosed which has two transmission bands. The first band is relatively narrow (about 1 nm) and encompasses a wavelength of about 1550 nm, while the second band is relatively broad (greater than 50 nm) to transmit wavelengths in a range of 1300-1400 nm. Accordingly, the filter can be used in wavelength division multiplexed communication systems to simultaneously select a payload channel having a wavelength of approximately 1550 nm, and a 1310 nm service channel.

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: A system and method analyze raw data derived from a manufacturing control facility, the manufacturing control facility for manufacturing at least one device by execution of a sequence of assembly operations. A preprocessor is used to receive the raw data from the manufacturing control facility and to configure the raw data into a predetermined database format. The raw data after being configured by the preprocessor is stored into a database. A server transmits queries and results between the database and at least one user terminal. The results transmitted by the server are displayed on at least one graphical user interface at the user terminal, the results being indicative of at least one performance parameter of the assembly operations.

Abstract: A WDM ring transmission system is provided whereby each optical signal is first dropped from the ring, supplied to an amplifier, and then input to an optical receiver. Typically, a filtering element is also provided either prior to or after the amplifier. The amplifier increases the power of the transmitted optical signal so that the optical signals can be transmitted over greater distances, and the filtering element minimizes any adjacent channel cross-talk light fed to the receiver. Moreover, since the amplifier only amplifies the dropped channel, excessive noise accumulation due to non-uniform spectral gain can be avoided. In addition, channels can be arbitrarily assigned to add/drop elements along the ring. A simplified amplifier design is further disclosed.

Abstract: A fiber grating package which substantially reduces Bragg wavelength variations resulting from axial strain on a fiber. The package includes a fiber segment including a Bragg grating. The segment is fixed between two points separated by a distance less than the length of the segment. As a result, the grating is bent to allow bending or rotation of the segment in response to changes in the relative positions of the ends of the fiber segment. In one embodiment, the package may include a temperature control structure and control electronics for heating the grating to a stable desired temperature using temperature feedback. Electronic control can be internal or external to the package depending size requirements for the package.

Abstract: An optical device is provided which separates one or more optical channels from a plurality of optical channels, each at a respective wavelength, and provides a length of dispersion compensating fiber for the one or more separated optical channels.

Abstract: A testing circuit is provided for determining the Q-factor of an optical communication system. In the testing circuit, a variable attenuator attenuates a received optical signal in response to an attenuator control signal. A first optical-to-electrical converter converts a first portion of the attenuated optical signal into an electrical data signal. A second optical-to-electrical converter converts a second portion of the attenuated optical signal into a first power indication signal. A decision circuit detects high and low data bits in the electrical data signal based on a plurality of threshold voltage signals, and provides decision signals indicative of the results of these determinations. An error monitoring circuit receives the decision signals, determines the bit error rate of the incoming optical signal for the plurality of threshold voltages, and provides bit error rate signals.

Abstract: In accordance with the present invention, an optical device includes a bandsplitter for separating a wavelength division multiplexed signal into a first and second group of channels. Transmission of one or more channels within the first group of channels is suppressed by one or more filtering elements positioned within a transmission path. The one or more suppressed channels correspond to channels to be added to the wavelength division multiplexed signal. By splitting the multiplexed optical signal into separate wavelength bands, channels previously designated as add/drop channels and their associated components, do not have to be altered with the introduction of additional channels into a WDM or DWDM network. An add/drop module optically communicates with the bandsplitter to add/drop one or more of the channels included in the multiplexed optical signal.

Abstract: A controller sets polishing parameters and automatically supplies materials needed for polishing to a polishing unit in accordance with a type of connector to be polished. The controller may also control the duration and pressure applied during polishing. Washing and any repeating of polishing may also be automated. Once polishing is complete, the connector may be inspected to determine if it has been satisfactorily polished. If not, the polishing parameters may be altered and the connector is repolished and reinspected.

Abstract: The present invention provides a system and method for intelligently shutting down an optical energy source in a communication system having optical amplifiers upon detection of a system failure.