Cambridge Enterprise Limited

Dow Corning Corporation

British Telecommunications Public Limited Company

Ian H White

Richard Penty

Michael Crisp

Sithamparanathan Sabesan

Jon Vierling Degroot, Jr

Terry Clapp

Joseph Beals

Adrian Wonfor

Richard S Linton

John E Carroll

Zhe Fu

Nikolaos Bamiedakis

Nikolas Bamiedakis

David G Cunningham

Jonathan D Ingham

Jon Degroot

A system for the distribution of RFID signals to a remote antenna or a remote antenna network comprising: a central control module to generate signals and control the protocol operations; cable, in particular twisted pair cable, connecting the central module to one or more antenna subsystems carrying substantially baseband representations of the reader to tag modulation and tag to reader modulation.

RFID systems

We describe an RFID tag reading system comprising a plurality of transmit/receive antennas to provide spatial transmit/receive signal diversity, and a tag signal decoder. The system combines received RF signals from the antennas, and the antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another. The system performs a tag inventory cycle comprising a plurality of tag read rounds, each having a set of time slots during which a said tag is able to transmit tag data including a tag ID. The system is configured to perform, during a tag inventory cycle, one or both of: a change in a frequency of the tag interrogation signals transmitted simultaneously from the plurality of antennas, and a change in a relative phase of a the RF tag interrogation signal transmitted from one of the antennas with respect to another.

RFID tag interrogation systems

We describe a methods of locating an RFID tag. One method transmits tag location signals at a plurality of different frequencies from a plurality of different antennas spaced apart by more than a near field limit distance. The processing determines a phase difference at the plurality of different frequencies by determining a phase difference between either i) two or more of the transmit signals resulting in a maxima in the returned signal RSSI or ii) a first transmit signal and its corresponding return signal. The range determining uses return signals weighted by signal strength. Further data which may be used for averaging may be generated by using the above techniques along with changes in the polarisation state of the transmit and receive antennas and/or physical reconfiguration of the antennas (e.g. switch the transmit and receive elements).

RFID tag location systems

The present invention provides an apparatus comprising a plurality of planar waveguides and method of making the same. The apparatus includes first, second, and third layers formed above a substrate and adjacent each other. The second layer is formed between the first and third layers of a material and comprises a plurality of organofunctional siloxane-based resin or polymer waveguides. Each waveguide has an input on one edge of the second layer and an output on one edge of the second layer so that the input and output are on different line-of-sight paths. The plurality of waveguides is formed such that intersections of the waveguides occur at approximately right angles and the outputs and inputs located on edges that are opposite one another are offset from each other in a direction that is perpendicular to the direction of the corresponding input or output signal.

Integrated planar polymer waveguide for low-loss, low-crosstalk optical signal routing

The present invention provides a planar waveguide. In one embodiment, the planar waveguide includes first and third layers formed above a substrate and adjacent each other. The first and third layers are formed of a first material having a first index of refraction. The planar waveguide also includes a second layer formed between the first and third layers of a second material having a second index of refraction that is larger than the first index of refraction. The planar waveguide further includes a plurality of organo-functional siloxane based resin or polymer waveguides formed in the second layer. Each organo-functional siloxane based resin or polymer waveguide has an input on one edge of the second layer and an output on one edge of the second layer so that the input and output are on different line-of-sight paths. The plurality of organo-functional siloxane based resin or polymer waveguides is formed such that intersections of the plurality of organo-functional siloxane based resin or polymer waveguides occur at approximately right angles.

A duplex optical fiber link is provided that includes two bi-directional optical fiber links. Each of the bi-directional links includes a multimode optical fiber and an optical transceiver connected to each of the ends of each of the fibers. Each of the optical transceivers includes a bi-directional optical multiplexer (MUX) that is configured to simultaneously optically couple optical data signals produced by a laser diode of the transceiver into an end of one of the fibers and to optically couple an optical data signal passing out of the end of one of the fibers onto a photodiode of the transceiver. The laser diodes operate at a data rate of at least 10 Gb/s such that each optical transceiver transmits and receives optical data signals at an aggregate data rate of at least 20 Gb/s. Consequently, the bi-directional duplex optical link has an aggregate data rate of at least 40 Gb/s.

High-speed optical transceiver, a bi-directional duplex optical fiber link, and a method for providing a bi-directional duplex optical fiber link

Polarization switching in active devices

An opto-electronic switch which shows a good signal rejection ratio between modes is also of particularly small dimensions. The switch comprises a semiconductor laser 1 having four contacts 12, 12', 13, 13' which provide gain guiding under two stripe windows 18, 19. By varying the bias currents supplied to the individual contacts 12, 12', 13, 13', or inputting optical control signals to the waveguiding channels under the stripe windows 18, 19, different configurations of optical output from the laser 1 can be achieved. The two contacts, 12, 12' and 13, 13', associated with each stripe window 18, 19 are effectively a signal stripe contact with a discontinuity. It is thought that diffractive transverse coupling at the discontinuity allows the use of a shorter device than in known directional switches. With feedback, the switch operates as a memory device. The switch finds particular application in optical communications, for instance in signal routing.

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Cambridge, United Kingdom

Ian H White