Telcordia Technologies, Inc.

Bell Communications Research, Inc.

Bell Telephone Laboratories

Other

At&t Bell Laboratories

University of Central Florida Research Foundation, Inc.

Tellium, Inc.

Janet L Jackel

Shahab Etemad

Paul Toliver

Thomas C Banwell

Rodney C Alferness

Ronald Charles Menendez

Sarry Habiby

Jane E Baran

Peter J Delfyett

Ted Kirk Woodward

Stefano Galli

Walter J Tomlinson, Iii

Anjali Agarwal

W John Tomlinson

David F Shallcross

Susan Hackwood

Lawrence L Buhl

Gregory L Baker

Jayantilal Patel

Vellayan Ramaswamy

Lawrence A Hornak

Joel Wright Gannett

Tamra Carpenter

Dwight Hugh Richards

Neophytos Antoniades

Ann Von Lehmen

Antonio d'Alessandro

Susan P Lyman

Nicholas E Schlotter

Gerard Beni

Wei Xin

Ronald Menendez

Thomas Banwell

A high data rate optical signal is inverse multiplexed into a multitude of lower-rate tributaries, each of which is coded by its unique OCDM code, and the combined coded tributaries are injected into a common phase scrambler. Coherent summation of these optically encoded tributaries pass through a shared phase or phase and frequency scrambler before exiting the secure location. The setting of the scrambler acts as the key. The authorized recipient with the correct key retrieves the ones and zeros of the several decoded signals.

OCDM-based all optical multi-level security

A system and methods are provided for converting a first temporally short and spectrally broad optical pulse into a train of spectrally narrow and distinct optical pulses. This involves receiving, on a first I/O channel, the first optical pulse associated with a plurality of wavelengths and performing wavelength division demultiplexing on the first optical pulse at an optical unit housed on an optical chip to output a plurality of second optical pulses on different ones of a plurality of second I/O channels, each of the second optical pulses associated with a unique wavelength range from the first optical pulse. This also involves receiving the second optical pulses at loop mirrors in the second I/O channels, wherein the second I/O channels are patterned as waveguides in the optical chip and reflecting, at the loop mirrors, the second optical pulses back to the optical unit.

System and methods for converting a temporally short and spectrally broad optical pulse into a train of spectrally narrow optical pulses

A system and method for transporting encrypted data having a transmitter and a receiver is provided. The transmitter generates a sequence of optical pulses, which are copied and output as identical channels. The identical channels are modulated by a plurality of modulators using data to generate a modulated data signal. Respective spectral phase encoders coupled to each of the plurality of data modulators encode respective modulated data signals using a plurality of mutually orthogonal phase codes that are individually associated with the respective spectral phase encoder. These encoded data signals are combined and code-scrambling by a spectral phase scrambler using a scramble code as an encryption key to generate an encrypted signal. A receiver reverses the encryption to extract the data.

System and method for OCDMA-based photonic layer security robustness to archival attack

A method for multiscale sampling for wide dynamic range electro-optic receivers is presented. The method comprises obtaining a signal, reproducing the signal into first and second signals, scaling one signal with respect to the other, modulating both signals with the same modulation function, and utilizing the resulting vector response function to invert the response of the link over a greater dynamic range than would otherwise be possible with a single instance of the modulated signal. The sealed modulation response may be obtained by splitting the signal into two polarizations and utilizing a modulator having different response for the two polarizations, or by utilizing two modulators.

Multiscale sampling for wide dynamic range electro-optic receivers

Apparatus and system for transmitting and receiving optical code division multiple access data over an optical network. The apparatus comprises a spectral phase decoder for decoding the encoded optical signal to produce a decoded signal, a time gate for temporally extracting a user signal from the decoded signal, and a demodulator that is operable to extract user data from the user signal. The system preferably comprises a source for generating a sequence of optical pulses, each optical pulse comprising a plurality of spectral lines uniformly spaced in frequency so as to define a frequency bin, a data modulator associated with a subscriber and operable to modulate the sequence of pulses using subscriber data to produce a modulated data signals and a Hadamard encoder associated with the data modulator and operable to spectrally encode the modulated data signal to produce an encoded data signal.

Phase chip frequency-bins optical code division multiple access

The present invention relates to a method and system for design and routing in telecommunications networks having transparent elements such as photonic switches. Transparent optical networks transmit signals optically, performing both switching and amplification photonically. As a result, transparent networks may be more economical than conventional 'opaque' optical networks that convert signals to electronic form at each network node because they do not require as much equipment for performing optical-electrical conversion. However, transparent networks pose new operational challenges. Physical-layer impairments that are repaired by optical-electrical-optical (OEO) regeneration can accumulate along (transparent) connection paths. To effectively deploy and utilize transparency, mechanisms to assure that impairment-feasible paths exist and can be identified in the network are required. The present invention provides: 1) a method for locating OEO-regeneration capability to assure the existence of impairment-feasible paths in a network and 2) a method for identifying impairment-feasible connection paths in a network of transparent and OEO-capable nodes. The first is a method related to network design, which models the design problem as a variation of a connected dominating set problem. The second is a method related to network routing, which transforms the impairment-aware routing problem into a shortest-path problem in an expanded network. The design methodology of the present invention employs both domination and connectability concepts to enable sparser placement of OEO regeneration capability within networks. Further, the routing methodology of the present invention provides a mechanism for finding feasible routes with respect to impairment constraints while minimizing the use of OEO interfaces to assure such feasibility.

Method and system for design and routing in transparent optical networks

Circuitry and a concomitant methodology for generating a burst support signal to augment an input bursty optical signal in an optical channel. The burst support signal is produced whenever the input bursty optical signal falls below a predetermined threshold. The burst support signal is the result of self-oscillation of a semiconductor optical amplifier and a tunable optical feedback loop. The wavelength of the self-oscillation is determined by the operating characteristic of the feedback loop.

Saturated amplifier generating burst support signal

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

A methodology and concomitant circuitry wherein an optical attenuator, having a range of settings including a minimum attenuation, is set to a pre-selected value less than the minimum attenuation whenever a loss of incoming signal power is detected in an optical path coupled to the attenuator.

Method and apparatus for stabilizing attenuators in optical networks

An apparatus and method for controlling the gain in an erbium-doped fiber amplifier (EDFA) incorporated into a multi-wavelength communication system so as to amplify each of the wavelength signals. The amplifier operates near to saturation so that, if one or more of the multi-wavelength signals is removed from the transmission, the remaining channels are increasingly amplified, leading to problems with other components in the system which depend upon intensity. According to the invention, an optical signal at a wavelength that is not within any of the transmission channels is selectively fed back around the amplifier and caused to lase in a wavelength-filtered ring-laser configuration. The lasing signal governs the saturation of the amplifier such that any gain shed by a disappearing data signal is predominately used by the lasing signal, not by the remaining data signals. Thereby, the data signals do not experience gain variations dependent upon the number of data signals being amplified. In a chain of amplifiers on a long link, the wavelength of the lasing signal is chosen to lie within the gain flat band of the amplifier and is output from the equalized amplifier with the same efficiency as all the transmission signals to be received by the next amplifier. Thereby, only the first amplifier needs to be equalized.

Automatic feedback gain control for multiple channels in a doped optical fiber amplifier

A method and system for unambiguously detecting fiber cuts in an optical network regardless of the number of EDFAs that are located between the fiber cut and the monitor point. In accordance with our invention, the power of a marker wavelength is compared to the power of a nearby spectral region. Where the comparison indicates that the power ratio is approximately equal to unity a flag is raised indicating that there is fiber cut. Where the comparison indicates that the power ratio is much greater than unity the flag is not raised. The monitoring point includes circuitry for detecting the ratio between the marker wavelength and the nearby spectral band and for indicating when there is a fiber cut.

Method and system for detecting loss of signal in wavelength division

A method and apparatus providing reducing crosstalk in optical cross-connects by configuring unused switching elements into a common switch state. The optical cross-connect may be a 2.sup.N .times.2.sup.N cross-connect which includes a plurality of dilated 2.times.2 switches each having a number of switch elements. A group of the switch elements connected between one or more inputs and one or more outputs of the cross-connect are suitably configured to provide one or more desired optical signal paths through the cross-connect. Unused cross-connect switch elements which are not part of any desired optical signal path are configured such that any unused switch elements in a given dilated 2.times.2 switch are placed in a common cross or bar switch state. The resulting cross-connect outputs will include at most one second order crosstalk term, as compared to conventional switch configurations in which a cross-connect output may have up to N second order crosstalk terms.

Reducing crosstalk in optical cross-connects by appropriate

Acousto-optic polarization converters can be used as the primary optical components in a multi-channel wavelength-routing switch (101). Switching efficiency is decreased and the polarization converted wavelength channels are shifted towards each other, however, when closely neighboring channels are selected simultaneously. This degradation has serious consequences for many applications of the acousto-optic polarization converter. By applying counterpropagating acoustic waves from opposite ends of a converter (400) and using an acoustic absorber (417) to separate the left and right sides of the converter at a defined coupler crossover length, L.sub.x, this deleterious degradation is substantially reduced. Specifically, by separating the primary acousto-optic interaction regions for the right propagating acoustic waves and the optical signal which polarization is to be converted, from the primary acousto-optic interaction regions for the left propagating acoustic waves and that same optical signal, so that adjacent closely neighboring wavelength channels are converted in opposite sides of the converter, channel shifting is reduced. Further, by using a partial absorber at the crossover length, L.sub.x, to separate the left and right converter sides, a flattened passband is created which decreases the consequences of any residual channel shifting.

Multi-channel wavelength-routing switch using acousto-optic polarization

A passband-flattened acousto-optic polarization converter (100) in which two acoustic waveguides (14, 20) are formed in a substrate and a separated by a small gap (18) such that the two acoustic waveguides act as a directional coupler in which acoustic power is transferred back and forth. An interdigitated transducer (12) launches a surface acoustic wave in the first acoustic waveguide, and an optical waveguide is formed in the middle of the second waveguide. A partial acoustic absorber (27) is formed over both acoustic waveguides at a crossover length at a distance from the transducer equal to the point at which the acoustic wave has transferred from the first to the second waveguides and back again. The partial absorber absorbs most of the acoustic amplitude with the attenuated acoustic amplitude being coupled back again to the second acoustic waveguide but at an opposite sign. A complete absorber (26) is formed over both acoustic waveguides at a distance from the transducer equal to approximately twice the crossover length such that the attenuated acoustic wave following the partial absorber and transferred to the second acoustic waveguide again transfers back to the first acoustic waveguide. The optical signal is exposed to an acoustic signal that increases to a maximum, decreases and then increases and decreases again with a smaller magnitude and reversed sign. The resultant frequency response has a significantly flattened shape for improved performance of the converter for use as a an optical switch or filter.

Growing community of inventors

Holmdel, NJ, United States of America

Janet L Jackel