Telefonaktiebolaget Lm Ericsson (publ)

Ericsson Ab

Marconi Communications Gmbh

Luca Poti

Antonella Bogoni

Fabio Cavaliere

Mirco Scaffardi

Gianluca Meloni

Gianluca Berrettini

Antonio Malacarne

Marco Secondini

Nicola Andriolli

Francesco Fresi

Luca Giorgi

Filippo Ponzini

Piero Castoldi

Enrico Forestieri

Claudio Porzi

Paolo Ghelfi

Tommaso Foggi

Tommaso Catuogno

Emma Lazzeri

Antonio D'errico

Alberto Bianchi

Giulio Colavolpe

Pier Giorgio Raponi

Gabriele De Angelis

Francesca Bontempi

Bimal Nayar

Gianluca Berettini

An optical receiver () comprising: a polarisation controller () arranged to receive as its input a first modulated optical signal having a first polarisation and an unmodulated optical carrier signal polarisation aligned with the first modulated optical signal, the first modulated optical signal having negligible spectral power density within a predetermined bandwidth, BW, around an optical spectrum of the unmodulated optical carrier signal; optical filter apparatus () having a main polarisation mode; and coherent optical receiver apparatus (), wherein the polarisation controller is arranged to apply polarisation rotations to the first modulated optical signal and the unmodulated optical carrier signal such that their polarisation is aligned to the main polarisation mode of the optical filter apparatus, the optical filter apparatus is arranged to receive and separate the unmodulated optical carrier signal from the first modulated optical signal, and the coherent optical receiver apparatus is arranged to receive said separated signals and perform coherent detection of the first modulated optical signal using as a local oscillator, LO, signal the unmodulated optical carrier signal.

Self-coherent optical transmission system and receiver

An Optical Dispersion Compensator (ODC) is disclosed, the ODC being suitable for managing chromatic dispersion of an optical signal for transmission over an optical fiber. The ODC comprises a first ODC unit () arranged on a first optical bus (), a second ODC unit () arranged on a second optical bus (), parallel to the first optical bus (), and a switching element () interconnecting the first and second optical buses () between the first and second ODC units (). The first and second ODC units () are operable to provide a delay to the optical signal that varies with frequency. The switching element () is configured, in a first state, to switch an optical signal received on one of the first or second optical buses () to the other of the first or second optical buses () and, in a second state, to maintain an optical signal received on one of the first or second optical buses () on the optical bus on which it was received (). Reflective elements () may be included in the ODC, providing bidirectional propagation through one of more ODC units.

Optical dispersion compensator

A method () of encoding communications traffic bits onto an optical carrier signal in a pulse amplitude modulation, PAM, format. The method comprises: receiving () bits to be transmitted; receiving () an optical carrier signal comprising optical pulses having an amplitude and respective phases; performing () PAM of the optical pulses to encode at least one respective bit in one of a pre-set plurality of amplitudes of a said optical pulse; and performing () phase modulation of the optical pulses to encode at least one further respective bit in a phase difference between a said optical pulse and a consecutive optical pulse.

Encoding and decoding communications traffic in a pulse amplitude modulation format and optical apparatus for same

A receiver module () is disclosed for receiving an optical input signal and generating an electrical output signal from the optical input signal. The receiver module comprises an input () for receiving an optical input signal and a polarising beam splitter () for splitting one of the optical input signal and a local recovery optical signal. The receiver module also comprises a multiport optical coupler () for coupling the outputs of the polarisation beam splitter and the other of the optical input signal and local recovery optical signal and outputting a plurality of outputs. The receiver module further comprises a first photodetector unit () for individually photodetecting the outputs of the multiport optical coupler and an optical modulation unit () for using each of the photodetected outputs to modulate a respective local conversion optical signal, where each local conversion optical signal has a different frequency from the other local conversion optical signals. The receiver module also comprises an optical coupler () for coupling the modulated local conversion optical signals to generate an optical output signal and a second photodetector unit () for photodetecting the optical output signal to generate an electrical output signal. Also disclosed are a method () and a multichannel receiver ().

Optical receiver and method of operation

An optical transmission method () comprising steps of receiving () a communication signal comprising symbols for transmission. The method comprises performing () linear amplitude modulation of an optical carrier with the communication signal to generate an amplitude modulated optical carrier. The method comprises performing low-pass filtering () to reduce a bandwidth of the symbols to less than a Nyquist bandwidth of the symbols. The method comprises transmitting () the amplitude modulated optical carrier. The method further comprises receiving () the amplitude modulated optical carrier following transmission and performing direct detection of the received amplitude modulated optical carrier to generate a received electrical signal; and determining () received symbols from the received electrical signal using an indication of a nonlinear impulse response of the direct detection.

Optical transmission method and optical receiver apparatus for determining received symbols from a received electrical signal using an indication of a nonlinear impulse response of the direct detection and without performing equalization following the direct detection

A method of transmitting communications traffic, the method comprising steps of receiving a sequence of communications traffic bits; and mapping the sequence of communications traffic bits onto a respective one of a plurality of transmission symbols for transmission during a symbol time. Each transmission symbol is identified by a respective first symbol identifier indicative of a respective one or more of a plurality, M, of wavelengths for a transmission signal and a respective second symbol identifier indicative of a respective one or more of a plurality, N, of optical fibers on which to transmit the transmission signal.

Method of transmitting communications traffic, transmitter and communications transmission system

A transceiver () comprising a receive part () configured to receive and detect a first signal carried on an optical carrier, wherein the signal is in a first part of a RF spectrum. The transceiver () further comprises a modulator () configured to modulate the same optical carrier with a second signal in a second part of the RF spectrum. The transceiver comprises a transmit part () configured to transmit the optical carrier modulated with the second signal. The first part of the RF spectrum is separate to the second part of the RF spectrum. The first signal and/or second signal are spectrally compressed signals.

Optical transceiver

A method of controlling a parameter in the generation of a coherent optical signal, the method comprising the steps of: receiving a set of signal samples relating to detection of a coherent optical signal; transforming the set of signal samples into a set of spectrum samples in the frequency domain, the set of spectrum samples being an estimation of the spectrum of the coherent optical signal; calculating at least one feedback variable based on the spectrum samples; and adjusting the parameter based on the at least one feedback variable.

Method of controlling the generation of a coherent optical signal and coherent optical signal control apparatus

An optical communication system comprising an optical link comprising an optical fiber, a first network element coupled to a first end of the optical link and a second network element coupled to a second end of the optical link. The first network element is configured to generate a first optical signal for transmission to the second network element, the first optical signal having a first propagation mode corresponding to a first guided mode of the optical fiber. The second network element is configured to generate a second optical signal for transmission to the first network element, the second optical signal having a second propagation mode, different to the first propagation mode, corresponding to a second guided mode of the optical fiber.

Optical communication system, method of bi-directional communication and method of operating a network element

A muxponder comprising: modulation format conversion apparatus comprising:

Muxponder and method of converting a plurality of tributary optical communications signals having a first bit rate into an optical line signal having a second, higher bit rate

An optical processing circuit, such as a combinatorial network, comprises an arrangement of optical logic gates suitable for use in combination with a switched optical node of the kind having at least first and second input ports and two output ports, the node being configurable into either a cross or a bar configuration, and in which the optical processing circuit is arranged so as to receive at least three optical input signals which respectively comprise a packet identifier signal PIH which identifies whether or not a first input signal is present at the first input port of the switched optical node, the first input port being assigned a higher priority than the second input port, a first destination address AH indicating the output port of the switched optical node to which a first information carrying signal, received at the first input port, is intended to be passed, and a second destination address AL indicating the output port of the switched optical node to which a second information carrying signal, received at the second input port, is intended to be passed, and in which the processing circuit is configured to generate from these three optical input signals the following optical output signals: a contention resolution control (CRC) signal which has a first value if a routing conflict is present and a second if it is not; and a switch control generation (SCG) signal indicating whether the associated switched optical node is to be set in a cross or bar configuration.

All optical processing circuit for conflict resolution and switch configuration in a 2&#xd7;2 optical node

A planar waveguide circuit comprises a first optical splitter to receive an input optical signal, a second optical splitter to receive a reference optical signal, a first optical signal combiner, and a second optical signal combiner. First and second optical waveguides are provided to couple first and second outputs of the first optical splitter to respective inputs of the first and second optical signal combiners. Third and fourth optical waveguides are provided to couple first and second outputs of the second optical splitter to respective inputs of the first and second optical signal combiners. A phase-shifter is provided located to affect the phase of an optical signal propagating in one of the third and fourth optical waveguides. The first and second optical splitters and the first and second optical signal combiners are arranged such that the first, second, third and fourth optical waveguides do not intersect one another.

Planar waveguide circuit and optical receiver

The present invention relates to Digital-to-Analog conversion in the optical or photonic domain. The present invention provides a digital-to-analog converter (DAC) () arranged to receive an N-bit digital optical signal () and to process the N-bit digital optical signal to generate an analog optical signal (). The DAC comprises a photonic circuit () arranged to adjust the amplitude of each bit of the N-bit digital optical signal dependent on the amplitudes of at least one of the other bits of the N-bit digital optical signal. The amplitudes are adjusted using a non-linear optical effect in order to generate respective outputs for each bit. The DAC also comprises a photonic combiner (145) arranged to combine the outputs for each bit to generate the analog output signal ().

Optical digital-to-analog converstion

An all-optical contention manager includes at least two inputs and at least two outputs. The outputs are configured to output signals to a Banyan switch. The contention manager detects and resolves routing contentions between incoming optical signals prior to outputting the signals to the Banyan switch. The signals have tags that include routing information. A photonic comparator in the contention manager compares the tags of incoming optical signals in order to detect contention.

All optical batcher banyan switch, batcher switch, banyan switch and contention manager

A synchronous packet switch comprises output modules, input modules, optical connections and a switch control unit. The output modules comprise optical receivers each configured to receive optical signals at a different wavelength. The input modules receive electric signals carrying data cells to be routed. Each input module comprises optical transmitters, each configurable to generate an optical signal at a different wavelength, and routing apparatus comprising output ports. Each output module has at least one output port allocated to it. The routing apparatus is configurable to route a received optical signal to a selected output port. The optical connections are arranged to couple output ports to respective output modules. The switch control unit controls routing of the optical signals from the transmitters to the output modules and generates a routing control signal for configuring the routing apparatus to route an optical signal from a transmitter to a selected output port.

Growing community of inventors

Pisa, Italy

Luca Poti