Abstract: A method of fabricating a micro-electrical-mechanical system (MEMS) transducer comprises the steps of forming a membrane on a substrate, and forming a back-volume in the substrate. The step of forming a back-volume in the substrate comprises the steps of forming a first back-volume portion and a second back-volume portion, the first back-volume portion being separated from the second back-volume portion by a step in a sidewall of the back-volume. The cross-sectional area of the second back-volume portion can be made greater than the cross-sectional area of the membrane, thereby enabling the back-volume to be increased without being constrained by the cross-sectional area of the membrane. The back-volume may comprise a third back-volume portion. The third back-volume portion enables the effective diameter of the membrane to be formed more accurately.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalisation of the air volumes above and below the membrane.

Abstract: A method of fabricating a micro-electrical-mechanical system (MEMS) transducer comprises the steps of forming a membrane on a substrate, and forming a back-volume in the substrate. The step of forming a back-volume in the substrate comprises the steps of forming a first back-volume portion and a second back-volume portion, the first back-volume portion being separated from the second back-volume portion by a step in a sidewall of the back-volume. The cross-sectional area of the second back-volume portion can be made greater than the cross-sectional area of the membrane, thereby enabling the back-volume to be increased without being constrained by the cross-sectional area of the membrane. The back-volume may comprise a third back-volume portion. The third back-volume portion enables the effective diameter of the membrane to be formed more accurately.

Abstract: A method of fabricating a micro-electrical-mechanical system (MEMS) transducer comprises the steps of forming a membrane (5) on a substrate (3), and forming a back-volume in the substrate. The step of forming a back-volume in the substrate comprises the steps of forming a first back-volume portion (7a) and a second back-volume portion (7b), the first back-volume portion (7a) being separated from the second back-volume portion (7b) by a step in a sidewall of the back-volume. The cross-sectional area of the second back-volume portion (7b) can be made greater than the cross-sectional area of the membrane (5), thereby enabling the back-volume to be increased without being constrained by the cross-sectional area of the membrane (5). The back-volume may comprise a third back-volume portion. The third back-volume portion enables the effective diameter of the membrane to be formed more accurately.

Abstract: A micro-electrical-mechanical system (MEMS) transducer comprises a layer of dielectric material having an electrode formed in the layer of dielectric material. A region of the layer of the dielectric material is adapted to provide a leakage path which, in use, removes unwanted charge from the layer of dielectric material.

Abstract: A method of fabricating a micro-electrical-mechanical system (MEMS) transducer comprises the steps of forming a membrane (5) on a substrate (3), and forming a back-volume in the substrate. The step of forming a back-volume in the substrate comprises the steps of forming a first back-volume portion (7a) and a second back-volume portion (7b), the first back-volume portion (7a) being separated from the second back-volume portion (7b) by a step in a sidewall of the back-volume. The cross-sectional area of the second back-volume portion (7b) can be made greater than the cross-sectional area of the membrane (5), thereby enabling the back-volume to be increased without being constrained by the cross-sectional area of the membrane (5). The back-volume may comprise a third back-volume portion. The third back-volume portion enables the effective diameter of the membrane to be formed more accurately.

Abstract: A MEMS device comprises a substrate having at least a first transducer optimized for transmitting pressure waves, and at least a second transducer optimized for detecting pressure waves. The transducers can be optimised for transmitting or receiving by varying the diameter, thickness or mass of the membrane and/or electrode of each respective transducer. Various embodiments are described showing arrays of transducers, with different configurations of transmitting and receiving transducers. Embodiments are also disclosed having an array of transmitting transducers and an array of receiving transducers, wherein elements in the array of transmitting and/or receiving transducers are arranged to have different resonant frequencies. At least one of said first and second transducers may comprise an internal cavity that is sealed from the outside of the transducer.

Abstract: The present invention provides a MEMS package, the MEMS package comprising a substrate which comprises a recess, and a MEMS device, situated in the recess.

Abstract: An integrated optical signal handling device comprises a substrate; a lightguiding waveguide formed in or on the substrate, the waveguide being arranged to carry an input optical signal; a resonator cavity region formed in or on the substrate, of a material having a rate of change of refractive index with temperature of greater magnitude than that of the substrate or waveguide material, the resonator region being adjacent to the waveguide so as to allow optical coupling between the waveguide and the res-onator region at one or more coupling wavelengths; and a heating and/or cooling arrangement operable to vary the temperature of at least the resonator region so as to cause corresponding variation in the coupling wavelengths.

Abstract: An optical device comprises a substrate having at least one light-guiding core and cladding material surrounding the core; a cladding-modifying element disposed alongside, at least in part, a portion of the light-guiding core, the cladding-modifying element being formed of a material different to the cladding material so that the refractive index difference between the material of the cladding-modifying element and the cladding material is dependent upon the temperature of the cladding-modifying element; and a heating and/or cooling arrangement for altering the temperature of the cladding-modifying element.

Abstract: An optical device comprises a substrate having at least one light-guiding core; a core-modifying element disposed at least partly within the light-guiding core, the core-modifying element being formed of a material different to the substrate material so that the refractive index difference between the material of the core-modifying clement and the light-guiding core is dependent upon the temperature of the core-modifying element; and a heating and/or cooling arrangement for altering the temperature of the core-modifying element.

Abstract: An optical device comprises a substrate having at least one light-guiding core and cladding material surrounding the core; a cladding-modifying element disposed alongside, at least in part, a portion of the light-guiding core, the cladding-modifying element being formed of a material different to the cladding material so that the refractive index difference between the material of the cladding-modifying element and the cladding material is dependent upon the temperature of the cladding-modifying element; and a heating and/or cooling arrangement for altering the temperature of the cladding-modifying element.

Abstract: The invention pertains to an optical waveguide component comprising a substrate, a core-matching refractive index lower cladding layer, a core layer, a core-matching refractive index upper cladding layer, a low refractive index upper cladding, wherein the core-matching refractive index lower cladding layer is deposited directly onto the substrate and has a thickness sufficient to avoid substantial capture and/or absorption by the substrate of a guided mode in the core layer, whereas slab modes, quasi-guided modes and/scattered light leak to the substrate. The components according to the invention allow high switching speeds and high confinement of a guided mode on the one hand and, on the other hand, absorption by the substrate of stray-light and radiation modes, which, in turn, leads to improved optical devices, such as optical switches with improved isolation.

Abstract: The invention pertains to a thermo-optical switch comprising a cascade of 1×M optical switches, gates for selectively blocking and unblocking the output paths of the cascaded switch, and means for driving the 1×M switches and the gates, which means are arranged to switch a data signal from an input path of the cascaded switch to one of the output paths, wherein the said means are also arranged to switch an unwanted signal, by means of a number of the remaining 1×M switches, to at least one of the remaining output paths. In the cascaded switch according to the invention, the generated heat is distributed evenly over the area of the switch and the overall amount of heat generated is reduced.

Abstract: The invention pertains to a polymeric optical waveguide device, such as an optical switch, splitter, phased array, Mach Zehnder interferometer, or the like, comprising at least one polymer waveguide channel embedded in a polymer cladding, said waveguide channel having a refractive index higher than that of the cladding and comprising at least one bend or curved section at least part of which has a refractive index contrast higher than that in the rest of the waveguide channel. The devices according to the invention are relatively compact.

Abstract: The invention pertains to a thermo-optical switch comprising at least one input channel, one output channel, one switching channel, and one heating element, where for at least part of the cross-sections of the switch the position of the heating element has been selected such that the difference in effective refractive index, in the switched state, between two of the output channels in said cross-section is at least 80% of the maximally attainable difference. As a result, the load on the switches can be reduced substantially, increasing their lifespan.

Abstract: The present invention is in the field of optical components, more particularly, polymeric optical components, even more particularly, thermo-optical components, electro-optical components or passive components. The present invention pertains to an optical component having an at least penta-layered polymer structure on a substrate comprising:A) a low refractive index lower cladding layer,B) a core-matching refractive index lower cladding layer,C) a core layer,D) a core-matching refractive index upper cladding layer, andE) a low refractive index upper cladding layer.With this specific layer structure an optimum traversal confinement can be obtained, which results in less loss of light and an improved switching efficiency.