Telefonaktiebolaget Lm Ericsson (publ)

Ericsson Ab

Mirco Scaffardi

Antonella Bogoni

Luca Poti

Piero Castoldi

Nicola Andriolli

Gianluca Berrettini

Paolo Ghelfi

Francesco Fresi

Isabella Cerutti

Emma Lazzeri

Bimal Nayar

Gianluca Berettini

An optical switch () comprising: inputs () to receive input optical signals at respective wavelengths and having planar wavefronts; conversion apparatus () to convert each input optical signal into a respective optical signal having a respective helical wavefront, each helical wavefront having a different orbital angular momentum, OAM; optical multiplexing apparatus () to receive each helical wavefront optical signal from the conversion apparatus and to multiplex the helical wavefront optical signals into an OAM multiplexed optical signal; and optical demultiplexing apparatus () comprising a plurality of outputs (), the optical demultiplexing apparatus arranged to: receive the OAM multiplexed optical signal; demultiplex the OAM multiplexed optical signal into a plurality of wavelength multiplexed optical signals each having a different OAM; reconvert each wavelength multiplexed optical signal from its helical wavefront into a respective planar wavefront; and deliver each planar wavefront wavelength multiplexed optical signal to a respective one of the outputs according to the respective OAM it had before reconversion.

Optical switching

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

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

An optical linear feedback circuit has an optical loop delay path () for recirculating a sequence of optical signals, and an output path for outputting delayed optical signals after circulating one or more times around the loop. A selector () is provided for selecting one or more of the delayed optical signals from the sequence, and an optical logic circuit () is coupled to carry out a logical operation on the selected delayed optical signals to create an optical feedback signal which is coupled to the optical loop delay path, so that the optical feedback signal can be added to the sequence of optical signals already circulating. By recirculating around a loop, each round trip can be regarded as equivalent to a shift of a shift register, so longer sequences can be built up without needing an additional storage cell for each shift function.

Optical linear feedback circuit

An analogue to digital converter is arranged to receive and process an analogue optical input signal to produce an N bit digital optical output signal quantised to 2levels, where N is greater than or equal to 2. The converter has an input for receiving the optical input signal and N processing channels which are each coupled to the input, at least one of said processing channels comprising an optical processing circuit arranged to generate a plurality of digital optical output signals. The optical processing circuit is arranged to change the state of each digital optical output signal corresponding to a respective different value of the analogue optical input signal, and an optical combining circuit for combining the optical output signals in order to generate one bit of the N-bit digital optical signal.

Optical analogue to digital converter

An optical transmitter apparatus comprises at least three input transmitters that each provide at an output an NRZ optical signal, at least two of the NRZ optical signals having substantially the same bit rate, each of the signals having a bit rate which is less than 100 Gbit/s and the sum of the bit rates of all of the at least three transmitters being equal to or greater than 100 Gbit/s, an NRZ to RZ converter associated with each transmitter which converts each NRZ signal into an optical RZ signal, an optical time division multiplexer which converts the RZ signals into at least two further signals, and a polarization multiplexer which processes the two further signals to provide two output signals of differing polarization.

Ethernet transmitter apparatus

An optical switch controller controls an optical interconnection network that variably connects at least one input data channel to a plurality of outputs channels via at least one switching element. An address reader module has at least one semiconductor optical amplifier optically processes an optical signal. The address reader module obtains information by reading a data tag from the input data channel, and outputs an address control signal based on the information. The address control signal can be used to control switching elements in the optical interconnection network.

Optical switch controller

A receiver scheme for optical signals in Return-to-zero (RZ) systems comprises a conventional receiver at the input of which is placed an all-optical decision element realized with nonlinear optical elements. This allows obtaining a substantial increase in performance compared with a simple conventional receiver optimized for NRZ signals. In particular, an optical decision is made up advantageously of two non-linear optical loop mirrors (NOLMs) arranged in cascade with an optical amplifier at the input and a pass-band filter at the output. The loops lengths may be different, as may be the splitting ratios of the couplers of the NOLMs.

Optical receiver scheme with all-optical decision element

An optical comparator circuit includes a first stage including an optical gate which receives the signals applied to the two inputs and produces at its output an N bit signal with each bit being representative of the logical expression A XOR B for a respective pair of bits of the words A and B, a second stage which comprises an optical gate having at least two inputs, a first input being connected to the output of the first stage by an optical connection having a first time delay, and a second input being connected to the output of the first stage through (N&#x2212;1) further optical connections, each further connection having a different associated time delay which is longer than the first time delay.

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Parma, Italy

Mirco Scaffardi