Abstract: An acoustic system and method is disclosed for providing spatial and temporal classification of a range of different types of sound producing targets in a geographical area. The system includes an optical signal transmitter arrangement for repeatedly transmitting, at multiple instants, interrogating optical signals into each of one or more optical fibres distributed across the geographical area and forming at least part of an installed fibre-optic communications network. An optical signal detector arrangement receives, during an observation period following each of the multiple instants, returning optical signals scattered in a distributed manner over distance along the one or more of optical fibres.

Abstract: Described herein are methods and systems of distributed acoustic sensing, such as in an urban or metropolitan area involving a dedicated and established fibre optic communications network including a data centre. In general, the disclosed method and system includes the steps of (a) selecting an optical fibre cable installation having a path extending across a selected geographical area, the optical fibre cable installation including a bundle of optical fibres and forming part of a fibre-optic communications network, (b) determining characteristics associated with the optical fibre and/or the selected optical fibre installation, (c) transmitting outgoing light in the optical fibre, (d) receiving reflected light back scattered along the optical fibre, and (e) based on the reflected light and the determined characteristics, generating an alert signal representative of an acoustic event. The disclosed method and system are applied to detect acoustic events near or within the selected geographical area.

Abstract: An acoustic system and method is disclosed for providing spatial and temporal classification of a range of different types of sound producing targets in a geographical area. The system includes an optical signal transmitter arrangement for repeatedly transmitting, at multiple instants, interrogating optical signals into each of one or more optical fibres distributed across the geographical area and forming at least part of an installed fibre-optic communications network. An optical signal detector arrangement receives, during an observation period following each of the multiple instants, returning optical signals scattered in a distributed manner over distance along the one or more of optical fibres.

Abstract: Described herein are methods and systems of distributed acoustic sensing, such as in an urban or metropolitan area involving a dedicated and established fibre optic communications network including a data centre. In general, the disclosed method and system includes the steps of (a) selecting an optical fibre cable installation having a path extending across a selected geographical area, the optical fibre cable installation including a bundle of optical fibres and forming part of a fibre-optic communications network, (b) determining characteristics associated with the optical fibre and/or the selected optical fibre installation, (c) transmitting outgoing light in the optical fibre, (d) receiving reflected light back scattered along the optical fibre, and (e) based on the reflected light and the determined characteristics, generating an alert signal representative of an acoustic event.

Abstract: Described herein are methods and systems of distributed acoustic sensing, such as in an urban or metropolitan area involving a dedicated and established fibre optic communications network including a data centre. In general, the disclosed method and system includes the steps of (a) selecting an optical fibre cable installation having a path extending across a selected geographical area, the optical fibre cable installation including a bundle of optical fibres and forming part of a fibre-optic communications network, (b) determining characteristics associated with the optical fibre and/or the selected optical fibre installation, (c) transmitting outgoing light in the optical fibre, (d) receiving reflected light back scattered along the optical fibre, and (e) based on the reflected light and the determined characteristics, generating an alert signal representative of an acoustic event. The disclosed method and system are applied to detect acoustic events near or within the selected geographical area.

Abstract: Described herein are methods and systems of distributed acoustic sensing, such as in an urban or metropolitan area involving a dedicated and established fibre optic communications network including a data centre. In general, the disclosed method and system includes the steps of (a) selecting an optical fibre cable installation having a path extending across a selected geographical area, the optical fibre cable installation including a bundle of optical fibres and forming part of a fibre-optic communications network, (b) determining characteristics associated with the optical fibre and/or the selected optical fibre installation, (c) transmitting outgoing light in the optical fibre, (d) receiving reflected light back scattered along the optical fibre, and (e) based on the reflected light and the determined characteristics, generating an alert signal representative of an acoustic event.

Abstract: Described herein are methods and systems of distributed acoustic sensing, such as in an urban or metropolitan area involving a dedicated and established fibre optic communications network including a data centre. In general, the disclosed method and system includes the steps of (a) selecting an optical fibre cable installation having a path extending across a selected geographical area, the optical fibre cable installation including a bundle of optical fibres and forming part of a fibre-optic communications network, (b) determining characteristics associated with the optical fibre and/or the selected optical fibre installation, (c) transmitting outgoing light in the optical fibre, (d) receiving reflected light back scattered along the optical fibre, and (e) based on the reflected light and the determined characteristics, generating an alert signal representative of an acoustic event. The disclosed method and system are thereby configured to detect acoustic events near or within the selected geographical area.

Abstract: Described herein are methods and systems of distributed acoustic sensing, such as in an urban or metropolitan area involving a dedicated and established fibre optic communications network including a data centre. In general, the disclosed method and system includes the steps of (a) selecting an optical fibre cable installation having a path extending across a selected geographical area, the optical fibre cable installation including a bundle of optical fibres and forming part of a fibre-optic communications network, (b) determining characteristics associated with the optical fibre and/or the selected optical fibre installation, (c) transmitting outgoing light in the optical fibre, (d) receiving reflected light back scattered along the optical fibre, and (e) based on the reflected light and the determined characteristics, generating an alert signal representative of an acoustic event. The disclosed method and system are thereby configured to detect acoustic events near or within the selected geographical area.

Abstract: Described herein are methods and systems of distributed acoustic sensing, such as in an urban or metropolitan area involving a dedicated and established fibre optic communications network including a data centre. In general, the disclosed method and system includes the steps of (a) selecting an optical fibre cable installation having a path extending across a selected geographical area, the optical fibre cable installation including a bundle of optical fibres and forming part of a fibre-optic communications network, (b) determining characteristics associated with the optical fibre and/or the selected optical fibre installation, (c) transmitting outgoing light in the optical fibre, (d) receiving reflected light back scattered along the optical fibre, and (e) based on the reflected light and the determined characteristics, generating an alert signal representative of an acoustic event.

Abstract: A system and method that enforces one or more policy rules on user-allocated bandwidth portions of the overall system bandwidth, for example in an optical fiber transmission system. The policy rules may limit, for example, the range of optical wavelengths, the acceptable range on the output-power-spectral density and/or the total per-band optical power within the user-allocated bandwidth that a user may provide on the system. The system may include one or more user control units that receives respective user output signals and applies all policy rules. The resulting optical output(s) of the UCU(s) may be provided an optical transmission path for transmission to a receiving terminal. In the receiving terminal, one or more UCU(s) may apply receiver policy rules, for instance by limiting the range of wavelengths transmitted to a receive subsystem.

Abstract: A system and method that enforces one or more policy rules on user-allocated bandwidth portions of the overall system bandwidth, for example in an optical fiber transmission system. The policy rules may limit, for example, the range of optical wavelengths, the acceptable range on the output-power-spectral density and/or the total per-band optical power within the user-allocated bandwidth that a user may provide on the system. The system may include one or more user control units that receives respective user output signals and applies all policy rules. The resulting optical output(s) of the UCU(s) may be provided an optical transmission path for transmission to a receiving terminal. In the receiving terminal, one or more UCU(s) may apply receiver policy rules, for instance by limiting the range of wavelengths transmitted to a receive subsystem.

Abstract: A system and method that enforces one or more policy rules on user-allocated bandwidth portions of the overall system bandwidth, for example in an optical fiber transmission system. The policy rules may limit, for example, the range of optical wavelengths, the acceptable range on the output-power-spectral density and/or the total per-band optical power within the user-allocated bandwidth that a user may provide on the system. The system may include one or more user control units that receives respective user output signals and applies all policy rules. The resulting optical output(s) of the UCU(s) may be provided an optical transmission path for transmission to a receiving terminal. In the receiving terminal, one or more UCU(s) may apply receiver policy rules, for instance by limiting the range of wavelengths transmitted to a receive subsystem.

Abstract: A system and method that enforces one or more policy rules on user-allocated bandwidth portions of the overall system bandwidth, for example in an optical fiber transmission system. The policy rules may limit, for example, the range of optical wavelengths, the acceptable range on the output-power-spectral density and/or the total per-band optical power within the user-allocated bandwidth that a user may provide on the system. The system may include one or more user control units that receives respective user output signals and applies all policy rules. The resulting optical output(s) of the UCU(s) may be provided an optical transmission path for transmission to a receiving terminal. In the receiving terminal, one or more UCU(s) may apply receiver policy rules, for instance by limiting the range of wavelengths transmitted to a receive subsystem.

Abstract: The present invention provides a method of storing data in an optical data storage device. The method comprises the step of encoding information and determining a multi-channel grating structure for the encoded information. The method further comprises the step of applying the grating structure to an optical waveguide in a manner such that in use the multi-channel grating will effect a change of a property of optical radiation that passes through the waveguide. The change of the property is characteristic for the encoded information. The present invention further provides an optical read only memory having a multi-channel grating.

Abstract: A data storage device comprising: a photosensitive optical waveguide having a predetermined structure photosentively formed therein; a package for mounting the waveguide on; an optical interface interconnected to the waveguide and adapted to temporarily attach to optical interrogation devices for receiving optical signals for interrogation of the optical properties of the predetermined structure.

Abstract: The present invention provides a multi-order dispersion compensation device comprising a plurality of concatenated dispersion compensation units of different order n. Each of the units comprises at least two chirped Bragg gratings of order n+1 which are concatenated and have opposing group delay profiles.

Abstract: The present invention provides a method and apparatus for obtaining a measure of the chromatic dispersion of a fibre bragg grating, the method comprising: disposing the grating in a reflection arm of an interferometer; inputting probe laser light into the interferometer; stepping the wavelength of the light across the reflection bandwidth of the grating, while at each step modulating the wavelength by a wavelength modulation less than the size of the respective step, and thereby producing a resulting phase modulation; and demodulating the phase modulation and determining therefrom a measure of the chromatic dispersion.