British Telecommunications Public Limited Company

British Telecommunications Corporation

Ericsson Ab

Derek Nesset

Kevin Smith

David Graham Moodie

Julian Kazimierz Lucek

Paul Gunning

David Cotter

Alan M Hill

David Wake

Mark Edward Scopes

Steven Alleston

Martin C Tatham

Justin Kang

Russell P Davey

Dominique David Marcenac

Paul Harper

Davey Russell

Anthony E Kelly

Albert Rafel

Benoit Charbonnier

Mark Wilkinson

Alan Michael Hill

The present invention relates to the introduction of an outstation into an optical network. The optical network has a central station, and a plurality of previously introduced outstations which are optically connected to the central station. The network is operable in: a normal operating state in which data traffic is received from previously introduced outstations at a normal data rate; and, a set-up state in which the transmission of data traffic from the previously introduced outstations is restricted relative to the normal state, the method including the step of: when the network is in the set-up state, performing a set-up operation for introducing the outstation into the optical network, the set-up operation involving the transmission of set-up data from the outstation being introduced, wherein the set-up data is transmitted at a reduced rate relative to the normal operating rate.

Method of introducing an outstation into an optical network and outstation therefor

A PON in which parallel optical fiber paths are provided between dual OLTs and the ONTs, one of the optical fiber paths providing an active connection and the other optical fiber path providing a standby connection. Respective VLANs may be formed over the parallel optical fiber paths. If performance indicators, for example Ethernet continuity check messages, indicate that an ONT is no longer in communication with the OLT then data may be sent via the VLAN associated with the standby connection.

Communications network

An optical signal transmission apparatus for transmitting a plurality of data signals comprising a plurality of inputs for receiving a respective one of the data signals and delivering the respective data signal with a controlled phase and at a controlled data rate. A plurality of optical carrier signals having different wavelength is generated. Each of a plurality of first modulators is operative for modulating a respective one of the optical carriers with a respective data signal to provide a first-modulated optical carrier signal. An optical signal-routing device has a plurality of input ports, each port being for receiving a respective one of the first-modulated optical carrier signals and delivering it to the output port of the device. The apparatus further comprises further modulators for further modulating each of the first-modulated optical carrier signals in dependence upon a clock to provide a plurality of further-modulated optical carrier signals; and a feedback arrangement, including the optical signal-routing device, for feeding back a proportion of each of the further modulated optical carrier signals to a respective input for controlling the phase and rates at which the input delivers the data signal to the first modulator in dependence upon the further modulation to thereby synchronize each input data signal to the clock. The optical signal-routing device delivers each of the further-modulated signals applied to its output to a respective input along a path which is dependent upon the wavelength of the signal.

Optical signal transmission

An optical pulse source includes a gain-switched semiconductor laser diode. Light from a continuous wave source is opitically coupled into the laser cavity. Light output from the laser cavity passes through an electro-optic amplitude modulator. Synchronized modulating signals are applied to the semiconductor diode and to the amplitude modulator. The source outputs short low-jitter low-pedestal optical pulses and is suitable for use, for example, in a broadband optical network operating at thigh bit rates of 100 Gbit/s or more, or in an optical interconnect.

Optical pulse source

A semiconductor optical amplifier has an optical path from its input to its output through an optical amplification region, the path having a length that exceeds 1 mm. In use, the amplifier is fed at its input with a modulated optical signal that is modulated at a given bit rate, and a target wave, so that the amplifier produces modulation of the target wave according to the modulation of the optical signal. The path length is selected to be longer than that at which optical saturation occurs. The gain of the amplifier exhibits a &minus;3 db bandwidth that extends beyond 20 GHz in respect of the modulation bit rate. The amplifier may also be used for four wave mixing.

Optical amplifier

Optical and gate

Generation of radio frequency modulated optical radiation

An optical pulse source includes a gain-switched semiconductor laser diode (1). Light from a continuous wave source (3) is optically coupled into the laser cavity. Light output from the laser cavity passes through an electro-optic amplitude modulator (2). Synchronised modulating signals are applied to the semiconductor diode and to the amplitude modulator. The source outputs short low-jitter optical pulses and is suitable for use, for example, in a broadband optical network operating at high bit rates of 100 Gbit/s or more, or in an optical interconnect.

Optical Pulse source

Growing community of inventors

Ipswich, United Kingdom

Derek Nesset