Northern Telecom Limited

Nortel Networks Corporation

Itt Gallium Arsenide Technology Center

Piers James Dawe

George H Thompson

Ernst A Munter

Paul Anthony Kirkby

Adrian Paul Sparks

Robert William Spagnoletti

David A Spear

The invention seeks to provide an improved, bandwidth-efficient method and apparatus for acquiring and tracking bursts of data, or continuous data, of varying and unpredictable amplitude, extinction ratio, and phase. The system avoids the use of digital signal processing which is not practical at high data signal rates. The system also obviates encoding of the data signal using a line code, thereby extending the existing technology to give a significant increase in data throughput for the same available bandwidth. The system may treat acquisition of each data burst, comprising alternate synchronisation parts and data parts, ab initio.

Signal regenerator

An electrical switch (116) is disclosed having multiple inputs (214) and binary switches (312) operable to switch a signal from an input (214) via respective amplifiers (310). Amplifiers (310) are continuously operable and are provided with an auxiliary switching circuit (412) which provides the amplifier with a fixed voltage input signal when the associated input (214) is not selected. Response time upon selection of an amplifier (310) and crosstalk from any non-selected amplifier is minimised.

High speed switch

The invention seeks to provide an improved method and apparatus for detecting thresholding errors in a digital signal recovered from a transmitted signal, wherein a derived threshold error signal varies linearly with the threshold error. Extraction of a threshold error signal linearly related to the actual threshold error enables increased speed of reaction of a threshold control circuit.

Method & apparatus for tracking characteristics of a data stream and a

An ATM switch has an ATM switch core comprising an N.times.N optical cross-connect core and a set of N port cards, each including a selector. Associated with each port card is a satellite. Wavelength shift keyed signals that are wavelength division multiplexed are employed for routing ATM cells between the satellites via the core by way of optical fibres.

Switched optical interconnect

A technique for achieving a substantially planar structure incorporating embedded vapor phase epitaxial growth involves the use of a window-frame shaped mask 40 of epitaxial growth resistant material to define a well in which embedded growth is to occur, and subsequently to ease mask registration problems in the location of a mask 60 employed while selectively removing unwanted material epitaxially grown on regions surrounding the well. Complementary format structures may also be formed in which epitaxial growth is provided up the sides of a mesa to substantially the same height as material grown on top of the mesa itself.

Semiconductor device manufacture

The gate of a gallium indium arsenide FET grown on an indium phosphide substrate comprises a top layer of GaInAsP (band gap 1.2 eV) a middle layer of GaInAs and a bottom layer of InP. This can be etched to produce an overhanging top layer which allows self-aligned gate contact metallization avoiding the registration problems of a further masking stage.

Growing community of inventors

Sawbridgeworth, United Kingdom

Piers James Dawe