Abstract: A method including forming a substrate to form a template which includes areas of high relief and areas of low relief; and forming a high refractive index diffraction grating in the template by adding high refractive index material to the template to form a continuous low relief surface The high refractive index material fills the areas of low relief and covers the areas of high relief of the template to form a high refractive index diffraction grating. The high refractive index diffraction grating includes the high refractive index material configured to have a low relief side corresponding to the continuous low relief surface and configured by the template to have a periodic side including areas of high relief and areas of low relief which periodically alternate in the first direction with the first periodicity and are interconnected by the high refractive index material.

Abstract: A method including forming a substrate to form a template which includes areas of high relief and areas of low relief; and forming a high refractive index diffraction grating in the template by adding high refractive index material to the template to form a continuous low relief surface. The high refractive index material fills the areas of low relief and covers the areas of high relief of the template to form a high refractive index diffraction grating. The high refractive index diffraction grating includes the high refractive index material configured to have a low relief side corresponding to the continuous low relief surface and configured by the template to have a periodic side including areas of high relief and areas of low relief which periodically alternate in the first direction with the first periodicity and are interconnected by the high refractive index material.

Abstract: A method including forming a substrate to form a template which includes areas of high relief and areas of low relief; and forming a high refractive index diffraction grating in the template by adding high refractive index material to the template to form a continuous low relief surface. The high refractive index material fills the areas of low relief and covers the areas of high relief of the template to form a high refractive index diffraction grating. The high refractive index diffraction grating includes the high refractive index material configured to have a low relief side corresponding to the continuous low relief surface and configured by the template to have a periodic side including areas of high relief and areas of low relief which periodically alternate in the first direction with the first periodicity and are interconnected by the high refractive index material.

Abstract: A communication system includes a plurality of first entities. Each of the plurality of first entities includes at least one database. The system also includes at least one second entity being dedicated to at least one of the plurality of first entities. The at least one second entity includes data from databases associated with the plurality of first entities. The system further includes a third entity for determining when one of the plurality of first entities malfunctions and for selecting another one of the plurality of first entities as a redundant entity. The at least one second entity is associated with the redundant entity and data is retrieved from the at least one second entity to process incoming requests to the redundant entity.

Abstract: An optical device includes an optical fiber having a core including multicomponent phosphate glasses, and a cladding surrounding the core, and a first fiber Bragg grating formed in a first portion of the core of the optical fiber and having an index modulation amplitude greater than 2×10?5.

Abstract: Authentication method for authenticating a mobile node to a packet data network, in which a shared secret for both the mobile node and the packet data network is arranged by using a shared secret of the mobile node and a telecommunications network authentication centre. In the method, the mobile node sends its subscriber identity to the packet data network together with a replay attack protector. The packet data network obtains authentication triplets, forms a session key using them, and sends back to the mobile node challenges and a cryptographic authenticator made by using the session key. The mobile node can then form the rest of the authentication triplets using the challenges and then form the session key. With the session key, the mobile node can check the validity of the cryptographic authenticator. If the authenticator is correct, the mobile node sends a cryptographic response formed using the session key to the packet data network for authenticating itself to the packet data network.

Abstract: A clock recovery device adapted to recover at least one clock signal from an optical input signal. The input signal includes at least one data signal. The clock recovery device-includes a first waveguide, a first optical resonator coupled to the first waveguide, a second optical resonator coupled to the first waveguide, and a combiner to combine signals provided by the first optical resonator and the second optical resonator in order to provide an output signal. A passband of the first optical resonator is matched with a first spectral peak of the input signal, and a passband of the second optical resonator is matched with a second spectral peak of the input signal such that the spectral separation between the first and the second peaks is equal to a clock frequency associated with a first data signal. The optical resonators store optical energy and provide an output also when the data signal is zero.

Abstract: An optical device includes an optical fiber having a core including multicomponent phosphate glasses, and a cladding surrounding the core, and a first fiber Bragg grating formed in a first portion of the core of the optical fiber and having an index modulation amplitude greater than 2×10?5.

Abstract: Authentication method for authenticating a mobile node to a packet data network, in which a shared secret for both the mobile node and the packet data network is arranged by using a shared secret of the mobile node and a telecommunications network authentication centre. In the method, the mobile node sends its subscriber identity to the packet data network together with a replay attack protector. The packet data network obtains authentication triplets, forms a session key using them, and sends back to the mobile node challenges and a cryptographic authenticator made by using the session key. The mobile node can then form the rest of the authentication triplets using the challenges and then form the session key. With the session key, the mobile node can check the validity of the cryptographic authenticator. If the authenticator is correct, the mobile node sends a cryptographic response formed using the session key to the packet data network for authenticating itself to the packet data network.

Abstract: The invention provides an apparatus and method for highly selective and sensitive chemical sensing. Two modes of laser light are transmitted through a waveguide, refracted by a thin film host reagent coating on the waveguide, and analyzed in a phase sensitive detector for changes in effective refractive index. Sensor specificity is based on the particular species selective thin films of host reagents which are attached to the surface of the planar optical waveguide. The thin film of host reagents refracts laser light at different refractive indices according to what species are forming inclusion complexes with the host reagents.

Abstract: Authentication method for authenticating a mobile node to a packet data network, in which a shared secret for both the mobile node and the packet data network is arranged by using a shared secret of the mobile node and a telecommunications network authentication center. In the method, the mobile node sends its subscriber identity to the packet data network together with a replay attack protector. The packet data network obtains authentication triplets, forms a session key using them, and sends back to the mobile node challenges and a cryptographic authenticator made by using the session key. The mobile node can then form the rest of the authentication triplets using the challenges and then form the session key. With the session key, the mobile node can check the validity of the cryptographic authenticator. If the authenticator is correct, the mobile node sends a cryptographic response formed using the session key to the packet data network for authenticating itself to the packet data network.

Abstract: A communication system includes a plurality of first entities. Each of the plurality of first entities includes at least one database. The system also includes at least one second entity being dedicated to at least one of the plurality of first entities. The at least one second entity includes data from databases associated with the plurality of first entities. The system further includes a third entity for determining when one of the plurality of first entities malfunctions and for selecting another one of the plurality of first entities as a redundant entity. The at least one second entity is associated with the redundant entity and data is retrieved from the at least one second entity to process incoming requests to the redundant entity.

Abstract: The invention provides an apparatus and method for highly selective and sensitive chemical sensing. Two modes of laser light are transmitted through a waveguide, refracted by a thin film host reagent coating on the waveguide, and analyzed in a phase sensitive detector for changes in effective refractive index. Sensor specificity is based on the particular species selective thin films of host reagents which are attached to the surface of the planar optical waveguide. The thin film of host reagents refracts laser light at different refractive indices according to what species are forming inclusion complexes with the host reagents.

Abstract: The invention provides an apparatus and method for highly selective and sensitive chemical sensing. Two modes of laser light are transmitted through a waveguide, refracted by a thin film host reagent coating on the waveguide, and analyzed in a phase sensitive detector for changes in effective refractive index. Sensor specificity is based on the particular species selective thin films of host reagents which are attached to the surface of the planar optical waveguide. The thin film of host reagents refracts laser light at different refractive indices according to what species are forming inclusion complexes with the host reagents.

Abstract: Authentication method for authenticating a mobile node to a packet data network, in which a shared secret for both the mobile node and the packet data network is arranged by using a shared secret of the mobile node and a telecommunications network authentication center. In the method, the mobile node sends its subscriber identity to the packet data network together with a replay attack protector. The packet data network obtains authentication triplets, forms a session key using them, and sends back to the mobile node challenges and a cryptographic authenticator made by using the session key. The mobile node can then form the rest of the authentication triplets using the challenges and then form the session key. With the session key, the mobile node can check the validity of the cryptographic authenticator. If the authenticator is correct, the mobile node sends a cryptographic response formed using the session key to the packet data network for authenticating itself to the packet data network.

Abstract: The invention relates to a method of producing waveguides by an ion exchange technique on a glass substrate. In order to be able to alleviate the tolerances allowed for the ion exchange technique, the waveguides are formed in the invention by diffusing ions which increase the refractive index away from a waveguide formed previously on the glass substrate and being wider than the optical waveguides to be produced, by using the ion exchange technique and a positive-type ion exchange mask.

Abstract: The invention relates to an adaptor device for coupling together optical waveguides of different types and a process for the production of such an adaptor device. The adaptor device of the invention comprises an optical waveguide produced on a glass substrate by ion-exchange technique, in the fundamental mode of which waveguide the field distribution of light changes adiabatically in the longitudinal direction of the optical waveguide from the field distribution of the fundamental mode of the optical waveguide produced by K-Na ion exchange to the field distribution of the fundamental mode of the optical waveguide produced by Ag-Na ion exchange.

Abstract: The invention relates to a method of producing optical waveguides by ion exchange technique in a glass substrate (1), the ion exchange between a source of ions (such as AgNO.sub.3) and the glass substrate (1) taking place within glass substrate surface areas (6) which do not comprise any ion exchange mask. In the method of the invention, the ion exchange mask is formed by depletion areas (5A, 5B) formed in the surface of the glass substrate.