Fujitsu Corporation

Rj Mears, LLC

British Technology Group Limited

Michael Charles Parker

Stuart Douglas Walker

Robert Joseph Mears

Robert J Mears

Stephen Thomas Warr

Makiko Hisatomi

Stuart Douglas University Of Essex Walker

Data is encrypted onto an electromagnetic beam by providing an electromagnetic beam having a signal component having a modal state, wherein the signal component is susceptible to accumulation of a geometric phase, and a reference component, transmitted along a path over at least part of which the signal component accumulates a geometric phase by transformation of its modal state from a first to a second modal state, from the second to at least one further modal state, and then back to the first modal state; and modulating with the data the geometric phase so accumulated, by modulating the modal state transformations. Data is decrypted from a received electromagnetic beam by corresponding processing of the received electromagnetic beam and by comparing an overall phase of the signal component with an overall phase of the reference component so as to retrieve the modulation.

Method and apparatus relating to secure communication

A compensator for compensating polarisation-mode dispersion, comprises a splitter () arranged to split light, according to the light's polarisation, between a first optical path and a second optical path; a combiner () arranged to combine light from the first optical path and the second optical path, and a monitor () for monitoring the light. An active wavelength-delay device () is provided in the first optical path and arranged such that components of the light travelling in the first optical path and having different wavelengths are subjected to different delays, the delays being selected according to an output from the monitor ().

Compensator for polarization-mode dispersion compensation

The invention relates to the field of grating structures. The invention provides a longitudinal grating having an aperiodic structure, wherein the grating has a selected response characteristic and any repeated unit cell in the structure is significantly longer than a characteristic length associated with the selected response characteristic.

Configurable aperiodic grating device

A fresenel zoned microstructured optical fiber is described. The fiber is constructed of concentric zones, each zone being defined by discontinuities in the refractive index. The refractive index within each zone may either be constant or may vary, for example each zone being a section of a parabola or hyperbola. The fiber may be used as a lens, for example for coupling light between fibers with different core sizes.

Fresnel zoned microstructured fibre and lens

A method for producing aperiodic gratings and waveguides with aperiodic gratings uses a simulated annealing process that starts with a random configuration of grating elements and iteratively computes a spectral response from a Fourier transform of the configuration of grating elements obtained in successive iterations. A cost function is computed as a convergence criterion. The aperiodic grating can be used, for example, as a filter in WDM applications.

Optical filter device with aperiodically arranged grating elements

A chromatic-dispersion compensator comprises a plurality of dispersive elements (Q in number. Q&#x2267;2) each exhibiting a dispersion characteristic D (&#x3bb;) that varies substantially as a polynominal function of wavelength, the polynomial function being of an order (P&#x2212;2) greater than 0, the dispersion characteristics being displaced in wavelength relative to each other such that the compensator has a net Pth-order dispersion characteristic Dthat is non-zero and does not vary substantially with wavelength an operating bandwidth.

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Colchester, United Kingdom

Michael Charles Parker