2159 results about "Wavelength-division multiplexing" patented technology

A multi-ladar sensor system is proposed for operating in dense environments where many ladar sensors are transmitting and receiving burst mode light in the same space, as may be typical of an automotive application. The system makes use of several techniques to reduce mutual interference between independently operating ladar sensors. In one embodiment, the individual ladar sensors are each assigned a wavelength of operation, and an optical receive filter for blocking the light transmitted at other wavelengths, an example of wavelength division multiplexing (WDM). Each ladar sensor, or platform, may also be assigned a pulse width selected from a list, and may use a pulse width discriminator circuit to separate pulses of interest from the clutter of other transmitters. Higher level coding, involving pulse sequences and code sequence correlation, may be implemented in a system of code division multiplexing, CDM. A digital processor optimized to execute mathematical operations is described which has a hardware implemented floating point divider, allowing for real time processing of received ladar pulses, and sequences of pulses.

Filtering of optical fibers and other related devices. High-energy methods for depositing thin films directly onto the ends of optical fibers can be used to produce high-quality, high-performance filters in quantity at a reasonable cost. These high-quality filters provide the high performance needed for many demanding applications and often eliminate the need for filters applied to wafers or expanded-beam filtering techniques. Having high-quality filters applied directly to optical fiber and faces permits production of high-performance, micro-sized devices that incorporate optical filters. Devices in which these filters may be used include spectroscopic applications including those using fiber optic probes, wavelength division multiplexing, telecommunications, general fiber optic sensor usage, photonic computing, photonic amplifiers, pump blocking and a variety of laser devices.

A method and apparatus for spatial multiplexing and demultiplexing of radio signals. A multichannel transmitter and receiver is integrated in a base station and coupled to an antenna array. Using digital radio signals containing previously known or non-Gaussian sequences and arranged in frames, the spatial information about each mobile unit is estimated on the basis of the signal received by the receiver for the reception and transmission frequencies. This is done by known sequences or by blind source separation methods. The respective paths of each mobile unit with the power above a predetermined threshold is isolated by spatial filtering in the presence of multiple channel paths in order to provide spatial demultiplexing. Simultaneously, the intended signal is transmitted in the direction of the main path of each mobile unit while protecting each mobile unit from signals transmitted in the direction of other mobile units by spatial filtering with cancelling constraints in order to provide spatial multiplexing.

A loss-less, optical add/drop multiplexer according to the present invention includes a rare earth-doped fiber amplifier integrated with a wavelength-selective fiber path coupled between two directional optical transfer devices for selectively adding and dropping optical signals from a multi-wavelength signal, such as a wavelength division multiplexed optical signal. One or more fiber gratings are disposed along the length of the rare earth-doped fiber amplifier or between segments of the rare earth-doped fiber so that at least one grating is used for reflecting each optical signal that is expected to be added to or dropped from the multi-wavelength optical signal. By using this configuration, appropriate amplification is provided to compensate for losses in the add, drop, and through paths.

A wavelength division multiplexed optical network has a restoration process to re-route one or more of the wavelengths, by dynamically determining possible restoration routes, and re-routing each wavelength along a chosen one of the possible restoration routes. A distributed dynamic search for restoration routes down to the optical layer, for wavelengths, gives faster and more scalable restoration than reconfiguring routing tables and enables much better utilisation of bandwidth than using predetermined restoration paths.

A wavelength division multiplexer is provided that integrates an axial gradient refractive index element with a diffraction grating to provide efficient coupling from a plurality of input optical sources (each delivering a single wavelength to the device) which are multiplexed to a single polychromatic beam for output to a single output optical receiver. The device comprises: (a) means for accepting optical input from at least one optical source, the means including a planar surface; (b) a coupler element comprising (1) an axial gradient refractive index collimating lens having a planar entrance surface onto which the optical input is incident and (2) a homogeneous index boot lens affixed to the axial gradient refractive index collimating lens and having a planar but tilted exit surface; (c) a diffraction grating, such as a Littrow diffraction grating, on the tilted surface of the homogeneous index boot lens which combines a plurality of spatially separated wavelengths from the optical light; and (d) means to output at least one multiplexed, polychromatic output beam, the means including a planar surface. The device may be operated in the forward direction as a multiplexer or in the reverse direction as a demultiplexer.

A system and method for linking optical wavelength division multiplexed (OWDM) networks by using wireless communications. Each optical channel in a OWDM network is coupled to a wireless wavelength division multiplexing (WWDM) channel by a WWDM transceiver, which transmits and receives data between OWDM networks. The WWDM transceiver may transmit and receive data in RF bands, where the assignment of different OWDM channels to different frequencies within the RF bands may depend upon the data rate or service supported by the OWDM channel. WWDM systems may also support communications between OWDM networks and individual users, such as those in a local multipoint distribution service.

The present invention relates to a monitoring system that observes the power and optical frequency of a frequency-modulated optical signal, which is utilized in the communication network employing the WDM (wavelength division multiplexing) method. The monitoring system comprises demultiplex means for demultiplexing the frequency-modulated optical signal outputted from a transmitter including frequency-modulation means, photo-detection means for converting the output of demultiplex means into an electrical signal, and extraction means for extracting the power and optical frequency of an optical signal by measuring the magnitude of an amplitude-modulated tone.

A mechanism for recovering reserved resources in a wavelength-division-multiplexed based photonic burst switched (PBS) network in response to resource non-availability. The PBS network includes edge and switching nodes, which optically communicate information formatted into PBS control and data burst frames. Each PBS data burst frame is associated with a PBS control burst frame. A PBS control burst is sent to reserve resources along a lightpath comprising a concatenation of lightpath segments linked between in ingress edge nodes, switching nodes and egress edge nodes. During a subsequent data burst, an unavailable resource is detected at one of the switching nodes. In response, a resource cancellation message (RCM) comprising a control burst is sent to upstream and/or downstream nodes along the lightpath. Upon receiving the RCM, the corresponding resource reservation is cancelled, freeing the network resources for subsequent bandwidth reservations and access.

The invention pertains to wavelength-agile optical filters suitable for wavelength-division-multiplexed (WDM) optical communications networks. More particularly, the invention pertains to optical filters with a wavelength reference that can be remotely switched to arbitrarily selectable channels on a standard grid, and to re-configurable optical communications networks employing same. The present invention provides a communication apparatus with a tunable filter which may be used in a wide range of applications including tuning an external cavity laser (ECL), selecting a wavelength for an add/drop multiplexer and providing channel selection and feedback for a wavelength locker. The filter may be utilized as a discrete component or in combination with circulators, wavelength lockers and gain medium. The filter may be implemented in whole or in part as part of a gain medium. The tunable filter exhibits a compact form factor and precise tuning to any selected wavelength of a predetermined set of wavelengths comprising a wavelength grid. The tunable filter may thus be utilized in telecom applications to generate the center wavelengths for any channel on the ITU or other optical grid.

A wavelength division multiplexer/demultiplexer is provided that integrates axial gradient refractive index elements with a diffraction grating to provide efficient coupling from a plurality of input optical sources (each delivering a single wavelength to the device) which are multiplexed to a single polychromatic beam for output to a single output optical source. The device comprises: (a) means for accepting an optical input from at least one optical source, the means including a planar surface; (b) a first coupler element comprising (1) a first axial gradient refractive index collimating lens having a planar entrance surface onto which the optical input is incident and (2) a first homogeneous index boot lens affixed to the first collimating lens and having a planar exit surface from which optical light exits; (c) a diffraction grating formed on the planar exit surface which combines a plurality of angularly separated diffracted wavelengths from the optical light; (d) a reflecting element for reflecting the plurality of diffracted wavelengths; (e) a second coupler element comprising (1) a second homogeneous index boot lens having a planar entrance surface onto which said plurality of diffracted wavelengths is incident and (2) a second axial gradient refractive index collimating lens affixed to the second homogeneous index boot lens; and (f) means for outputting at least one multiplexed, polychromatic output beam to an optical receiver, the means including a planar back surface. The device may be operated in either the forward or the reverse direction.

The present invention relates to a technology of an IP node for transferring IP packets accommodated in a wavelength division multiplexing optical signal. The optical IP node of the present invention includes a space switch unit supplied with a wavelength division multiplexing optical signal and a packet with another node destination and generating an optical signal with the self node destination and multiplexing the optical signal with another node destination and an optical signal caused by the packet together and generating the multiplexed signal, link failure detecting unit connected to an input side and an output side of the space switch unit, detecting link failure and generating a detection signal, an OAM packet transmitting unit for generating a monitoring packet at a predetermined time interval, and a traffic restoration control unit connected to the link failure detecting unit, selecting each optical signal depending on the wavelength in response to reception of the detection signal, switching the optical path and generating the optical signal. Each of the optical IP nodes carries out optical path switching on the wavelength division multiplexing optical signal and assignment of an IP packet to be transmitted to an optical signal and switching of the assignment. Thus, the number of optical wavelengths utilized for transmission can be reduced and the size of the optical IP node can be made small.

An architecture and method for performing coarse-grain reservation of lightpaths within wavelength-division-multiplexed (WDM) based photonic burst-switched (PBS) networks with variable time slot provisioning. The method employs extensions to the RSVP-TE signaling protocol, which uses various messages to reserve resources. A resource reservation request is passed between nodes during a downstream traversal of the lightpath route connecting a source node to a destination node via one or more switching nodes, wherein each node is queried to determine whether it has transmission resources (i.e., a lightpath segment) available during a future scheduled time period. Soft reservations are made for each lightpath segment that is available using information contained in a corresponding label. If all lightpath segments for a selected route are available, a reservation response message is sent back upstream along the route from the destination node to the source node. In response to receiving the response, the soft reservations are turned into hard reservations at each node.

A three-dimensional optical waveguide is formed by laminating planar substrates such as a plurality of lens substrates and, an isolator substrate and a wavelength division multiplexing filter, the optical substrates at least include a waveguide substrate having a waveguide and a reflecting surface. In the three-dimensional optical waveguide, the planar substrates are positioned by markers integrally formed on at least two of the planar substrates. Light directed into the waveguide is reflected by a reflecting surface and passes through the lens substrates and the isolator substrate.

An optical fiber sensor array is disclosed which includes a first sensor fiber and a first reference fiber coupled at one end thereof to one side of a first optical coupling. A first wavelength selective reflector is coupled to the other end of each of the first sensor fiber and the first reference fiber. A second sensor fiber is coupled at one end to one side of a second optical coupling. The other side of the second optical coupling is coupled to an opposite side of one of the first wavelength selective reflectors coupled on one side to the first sensor fiber and the first reference fiber. The array also includes a second wavelength selective reflector coupled to the other end of each of the second sensor fiber and the second reference fiber. The second wavelength selective reflectors are operative at a wavelength different from an operative wavelength of the first wavelength selective reflectors.

Methods and systems for silicon photonics wavelength division multiplexing transceivers are disclosed and may include, in a transceiver integrated in a silicon photonics chip: generating a first modulated output optical signal at a first wavelength utilizing a first electrical signal, generating a second modulated output optical signal at a second wavelength utilizing a second electrical signal, communicating the first and second modulated output optical signals into an optical fiber coupled to the chip utilizing a multiplexing grating coupler in the chip. A received input optical signal may be split into a modulated input optical signal at the first wavelength and a modulated input optical signal at the second wavelength utilizing a demultiplexing grating coupler in the chip. The first and second modulated input optical signals may be converted to first and second electrical input signals utilizing first and second photodetectors in the chip.

An optical network includes receiving inter-rack traffics from transmitter racks, converting by transmitters the inter-rack traffics to respective wavelength division multiplexing WDM optical signals, receiving and routing by a cyclic interleaver the optical signals from the transmitters to output ports in a cyclic manner, converting respective routed optical signals from the cyclic interleaver into respective electrical signals, and demodulating OFDM formats from respective converted optical signals containing signals for respective receiver racks.

A vector-matrix multiplier is disclosed which uses N different wavelengths of light that are modulated with amplitudes representing elements of an N×1 vector and combined to form an input wavelength-division multiplexed (WDM) light stream. The input WDM light stream is split into N streamlets from which each wavelength of the light is individually coupled out and modulated for a second time using an input signal representing elements of an M×N matrix, and is then coupled into an output waveguide for each streamlet to form an output WDM light stream which is detected to generate a product of the vector and matrix. The vector-matrix multiplier can be formed as an integrated optical circuit using either waveguide amplitude modulators or ring resonator amplitude modulators.

A fiber optic network transmits data between a hub node and a plurality of local nodes connected by at least one unidirectional fiber ring. Downstream data streams are carried on wavelength-division-multiplexed optical carriers from the hub node to the local nodes. An optical carrier corresponding to a specific wavelength carries downstream data streams to a specific local node. Downstream data streams are multiplexed onto an optical carrier via orthogonal frequency division multiplexing. A parallel signal detector in each local node detects all downstream optical carriers. A signal processing module demultiplexes the data stream from the optical carrier having the specific wavelength corresponding to the local node. An upstream data stream is multiplexed via orthogonal frequency division multiplexing onto an upstream optical carrier having the same specific wavelength and transmitted from the local node to the hub node. Upstream data awaiting transmission is allocated to specific subcarriers and time slots.

Data throughput rates are increased in an optical fiber communication system without requiring replacement of the existing optical fiber in a link. Channel throughput is increased by upgrading the components and circuitry in the head and terminal of an optical fiber communication system link. Aggregate throughput in a fiber optic link is increased beyond the range of conventional Wavelength Division Multiplexed (WDM) upgrades, while precluding the necessity of replacing existing fiber plants. The increase in system throughput is achieved by using advanced modulation techniques to encode greater amounts of data into the transmitted spectrum of a channel, thereby increasing the spectral efficiency of each channel. This novel method of increasing transmission capacity by upgrading the head and terminal of the system to achieve greater spectral efficiency and hence throughput, alleviates the need to replace existing fiber plants. Spectrally efficient complex modulation techniques can be supported by interface circuits with an increased level of signal processing capability in order to both encode multiple bits into a transmitted symbol and decode the original data from the received symbols.

The present invention overcomes problems associated with switch isolation, noise and crosstalk suppression, insertion loss, spurious reflections, wavelength tolerance, and compactness that are present in varying degrees in other add/drop systems. The present invention includes devices or components that include, but are not limited to high efficiency switchable gratings. In one embodiment of the invention, each of the “base” gratings have substantially identical spatial frequencies and each of the “vertex” gratings have substantially identical spacial frequencies. However, the “vertex” gratings have higher grating frequencies than the “base” gratings. In another embodiment of the invention, the “base” and “vertex” gratings have substantially the same grating frequencies. Further embodiments of the invention, for example, deal with multiple add/drop grating pairs, variations of fixed and switchable gratings, the use of grating pairs to spatially separate the wavelength division multiplexed components of input beams into individual beams, and the replacement of lenses and waveguides with detectors or emitters.

A WDM optical transmission system of the invention has a configuration where WDM light generated at a wavelength multiplexing station is transmitted via a plurality of stations such as optical add-drop stations, arranged on an optical transmission line, and control of the power of the optical signals of respective wavelengths included in the WDM light is performed in the wavelength multiplexing station and the optical add-drop stations. A device is provided which communicates between stations, optical signals including information related to the control state of the optical signal power in each station, so that after control of the optical signal power at an upstream station is complete, control of the optical signal power at the downstream station is executed. As a result, stable control in respective stations can be performed even at the time of increasing or decreasing the number of wavelengths.

A time-based switching method and system of SONET frames that utilize a common time reference is disclosed. Time is divided into a plurality of contiguous periodic time frames. A plurality of SONET frames is associated with a time frame; the plurality of SONET frames that are contained in each of the time frames is forwarded in a pipelined manner through the network switches. The system operates with high-speed wavelength division multiplexing (WDM) links. This switching method can be used to implement an all-optical SONET switching system.

A telecommunications module includes a main housing portion and a cover, the main housing portion defining a first sidewall, a front wall, a rear wall, a top wall, and a bottom wall, the cover defining a second sidewall when mounted on the main housing portion. An optical component located within the module receives an input signal from a signal input location of the housing and outputs an output signal toward a signal output location on the front wall. The telecommunications module is configured such that the signal input location can be selected to be either on the front wall or the rear wall of the main housing. The cover defines a protrusion extending from the second sidewall toward the main housing portion, the protrusion being selectively breakable to expose a recess on the front wall of the main housing portion that defines a signal input location.

The invention discloses a transmission method of uplink control signaling and a device thereof, relating the field of mobile communication and solving the problem of lacking a mechanism for transmitting uplink control signaling on space division multiplexing (SDM) PUSCH. The method comprises: determining the uplink control signaling target length corresponding to each transmission block or code stream; respectively obtaining the multiplexing information after uplink control signaling to be transmitted on each transmission block or code stream are multiplexed with uplink data; and transmitting the multiplexing information corresponding to each transmission block or code stream on PUSCH. The technical scheme provided by the invention is suitable for the transmission of uplink control signaling in LTE systems.

A modulator arrangement for modulating an optical signal using a quadrature phase shift key for use in an optical wavelength division multiplex (WDM) optical communications system comprising a laser (2) for producing an optical signal of a selected wavelength, which signal is split by a splitter (4), each part of said split signal being applied to a respective phase modulator (6, 8) each for which phase modulators is adapted to modulate the phase of the signal in dependence on a respective drive voltages. The phase of the output of at least one modulator (6) is shiftable at least in part by a phase shifter (10), the split signals being recombined by an optical recombiner (12) to form an optical phase shift key output, wherein the output power is monitored by a detector (20), the detector signal then being used to drive a feedback arrangement to control electrodes of the phase modulators (6, 8) and/or phase shifter (10).

A system for reducing reflection of an optical system can reduce or eliminate reflection at facets of a semiconductor gain medium and can suppress natural longitudinal modes produced within the semiconductor gain medium. In combination with external feedback, the system can allow more precise wavelength control of the light output of a laser, thereby allowing the laser to be used in a dense wavelength division multiplexing system. The system employs a patterned relief surface disposed on a facet of a gain medium. The patterned relief surface may be a "motheye" pattern having a plurality of conical posts disposed on the surface of the facet. The system may be combined with conventional devices, such as a Bragg reflector or a microelectromechanical component, to further improve wavelength control of a resonant optical cavity, thereby improving the operation of optical communications systems.

An antenna beamformer consisting of optical irises coupled to Wavelength Division Multiplexers (WDMs). The ports of the WDMs are coupled to lens ports, where each lens port corresponds to a different antenna beam. The optical irises are optical filters with selectable center frequencies and selectable passband widths. Selection of different center frequencies and passband widths enables the selection of different ports of the WDMs, which allows the selection of one or more antenna beams. The beamformer may also have controllable delay lines to provide for additional beam steering.

A wavelength-selective optical device for coupling of light at predetermined wavelength from one optical fiber waveguide to another using at least two gratings and cladding-mode assisted coupling is disclosed. The transfer of light is performed using intermediate coupling to one or more cladding mode of the waveguides. In the case when the fibers have physically different cladding's, an arrangement for transfer of light from one cladding to another is required. The disclosed coupler has no back-reflection, small insertion loss, and very high channel isolation. The device can be used in wavelength-division multiplexing networks.

The present invention provides a directionless optical architecture for reconfigurable optical add/drop multiplexers (ROADMs) and wavelength selective switches (WSSs). The directionless architecture utilizes a directionless wavelength switch coupled between client devices and ROADMs/WSSs to eliminate the need to hard-wire client devices to a wavelength division multiplexed (WDM) network. Accordingly, client device connections can be automatically routed without manual intervention to provide a highly resilient network design which can recover route diversity during failure scenarios. Additionally, the present invention minimizes deployments of costly optical transceivers while providing superior resiliency. Further, the present invention couples the directionless optical architecture and associated optical protection mechanisms with existing mesh restoration schemes to provide additional resiliency.