Abstract: A leak detection system performs actions based upon the type and location of the detected leak. A plurality of sensors and sensor types are used at various locations in a building where leaks are likely to occur. Upon detection of a leak, a sensor transmits an RF signal identifying the sensor. A controller receives the RF signal and performs actions associated with the identifier for the sensor. Actions may include selectively closing or opening valves and electrical connections. Notifications are also sent by the system to building owners or occupants.

Abstract: A leak detection and control system provides for remote user control of devices in responding to detected leaks of other problems. A plurality of sensors and sensor types are used at various locations in a building where leaks are likely to occur. Upon detection of a leak, a sensor sends an RF signal identifying the sensor. A controller receives the RF signal and performs actions associated with the identifier for the sensor. Actions may include selectively closing or opening valves and electrical connections. Notifications are also sent by the system to building owners, occupants, maintenance personnel or operators. An operator can contact the controller from a remote location via a telephone system or a network to check status and to activate devices.

Abstract: A semiconductor optical component is disclosed which comprises a current injection region and at least one electrically isolated region referred to as a first plateau, each region containing a contact layer of an alloy based on gallium arsenide, GaAs, deposited on a semiconductor material upper confinement layer. The component further comprises in the first plateau a dielectric material isolation layer on top of the contact layer. An attachment layer is disposed between the contact layer and the isolation layer to increase the adhesion of the isolation layer to the contact layer. A method of fabricating the above kind of component is also disclosed.

Abstract: A semiconductor optical component is disclosed which comprises a current injection region and at least one electrically isolated region referred to as a first plateau, each region containing a contact layer of an alloy based on gallium arsenide, GaAs, deposited on a semiconductor material upper confinement layer. The component further comprises in the first plateau a dielectric material isolation layer on top of the contact layer. An attachment layer is disposed between the contact layer and the isolation layer to increase the adhesion of the isolation layer to the contact layer. A method of fabricating the above kind of component is also disclosed.

Abstract: Two semiconductor layers of the laser form a tunnel junction enabling an electrical current for pumping the laser to pass from an N doped semiconductor Bragg mirror to a P doped injection layer belonging to the light-amplifying structure. The Bragg mirror co-operates with another mirror of the same type having the same doping to include said structure in an optical cavity of the laser. In a variant, the tunnel junction may be buried and located so as to constitute confinement means for said pumping current. The laser can be used in an optical fiber communications network.

Abstract: The energization current of an indium phosphide or gallium arsenide double channel semiconductor laser is confined within a laser stripe by near and far current blocking arrangements. The near current blocking arrangements are formed by a blocking junction formed in two lateral channels delimiting the stripe. The far current blocking arrangements are formed by an iron-doped semi-insulative layer grown epitaxially before the lateral channels are etched. A particular application is to the fabrication of pump lasers used in optical amplifiers of optical fiber links.