Abstract: An electrode for use in bio-electrochemical systems is described, including: a substantially planar electrode material; a frame comprising a non-conductive substance; and one or more first conductive substances linked or secured to the frame. Bio-electrochemical systems, racks for inserting the electrode, and methods of using the racks are also described.

Abstract: An aerial vehicle with a plurality of selectively collapsible arms capable of transitioning between an extended state and a contracted state is described. In the extended position, the distance between the main body of the vehicle and the rotor associated with each arm is maximized. In the contracted state, the distance between the main body of the vehicle and the rotor associated with each arm is minimized. In certain embodiments, each of the arms may include one or more tape springs that are biased to selectively move the associated one or more rotors of each arm between the retracted and extended states.

Abstract: An aerial vehicle with a plurality of selectively collapsible arms capable of transitioning between an extended state and a contracted state is described. In the extended position, the distance between the main body of the vehicle and the rotor associated with each arm is maximized. In the contracted state, the distance between the main body of the vehicle and the rotor associated with each arm is minimized. In certain embodiments, each of the arms may include one or more tape springs that are biased to selectively move the associated one or more rotors of each arm between the retracted and extended states.

Abstract: An imaging system includes a metering structure and a plurality of foldable members disposed around a periphery of the metering structure. Each foldable member in the plurality of foldable members includes an arm comprising a strain deployable composite and a reflector disposed on the arm. The arm in a respective foldable member in the plurality of foldable members is configured to hold the respective foldable member toward the metering structure in a first state and to hold the respective foldable member away from the metering structure in a second state such that the reflector of the respective foldable member forms part of a sparse aperture in the second state.

Abstract: An imaging system includes a metering structure and a plurality of foldable members disposed around a periphery of the metering structure. Each foldable member in the plurality of foldable members includes an arm comprising a strain deployable composite and a reflector disposed on the arm. The arm in a respective foldable member in the plurality of foldable members is configured to hold the respective foldable member toward the metering structure in a first state and to hold the respective foldable member away from the metering structure in a second state such that the reflector of the respective foldable member forms part of a sparse aperture in the second state.

Abstract: An imaging system includes a metering structure and a plurality of foldable members disposed around a periphery of the metering structure. Each foldable member in the plurality of foldable members includes an arm comprising a strain deployable composite and a reflector disposed on the arm. The arm in a respective foldable member in the plurality of foldable members is configured to hold the respective foldable member toward the metering structure in a first state and to hold the respective foldable member away from the metering structure in a second state such that the reflector of the respective foldable member forms part of a sparse aperture in the second state.

Abstract: An imaging system includes a metering structure and a plurality of foldable members disposed around a periphery of the metering structure. Each foldable member in the plurality of foldable members includes an arm comprising a strain deployable composite and a reflector disposed on the arm. The arm in a respective foldable member in the plurality of foldable members is configured to hold the respective foldable member toward the metering structure in a first state and to hold the respective foldable member away from the metering structure in a second state such that the reflector of the respective foldable member forms part of a sparse aperture in the second state.

Abstract: An aircraft ground collision detection system comprising: an object detection device for mounting on an aircraft and arranged to detect objects and output the location of each detected object; and a processor arranged to: receive the ground speed of the aircraft and the heading of the aircraft and the detected location of each detected object; predict the aircraft's path based on the ground speed and the heading; compare the predicted aircraft path with the object locations; and output an alert based on the overlap or proximity of the predicted aircraft path with the object locations. By predicting the path of the aircraft based on detected ground speed and heading, the system can accurately assess which detected objects pose a collision threat.

Abstract: A side pumped laser comprises an elongated gain medium (10) provided between an output coupler (20) and a counter reflector (15) and a pump source (65) configured to provide radiation to the gain medium (10) along a side axis of the gain medium, wherein the laser is configured such that radiation from the pump source is directly incident on the gain medium; and the pump source is provided proximate, adjacent or in contact with the gain medium. The laser material and compositions, geometries and dimensions are designed to both maximize laser performance and to permit the use of construction techniques commonplace in the production of equipment designed for optical telecoms systems to facilitate low cost high volume and miniaturization.

Abstract: An aircraft ground collision detection system comprising: an object detection device for mounting on an aircraft and arranged to detect objects and output the location of each detected object; and a processor arranged to: receive the ground speed of the aircraft and the heading of the aircraft and the detected location of each detected object; predict the aircraft's path based on the ground speed and the heading; compare the predicted aircraft path with the object locations; and output an alert based on the overlap and/or proximity of the predicted aircraft path with the object locations. By predicting the path of the aircraft based on detected ground speed and heading, the system can accurately assess which detected objects pose a collision threat. An object which is in relatively close proximity to the aircraft, but which does not lie on the path will be detected, but the system is capable of assessing that the object does not pose a collision risk.

Abstract: A side pumped laser comprises an elongated gain medium (10) provided between an output coupler (20) and a counter reflector (15) and a pump source (65) configured to provide radiation to the gain medium (10) along a side axis of the gain medium, wherein the laser is configured such that radiation from the pump source is directly incident on the gain medium; and the pump source is provided proximate, adjacent or in contact with the gain medium. The laser material and compositions, geometries and dimensions are designed to both maximise laser performance and to permit the use of construction techniques commonplace in the production of equipment designed for optical telecoms systems to facilitate low cost high volume and miniaturisation.

Abstract: A buried heterojunction laser optically coupled with a buried waveguide electro-absorption (EA) optical modulator via an active layer is fabricated on a substrate carrying a number of deposited semiconductor layers. The laser component includes a laser current conduction region and an adjacent laser current confinement region. The waveguide component includes a waveguide current confinement region comprising first and second current blocking structures formed from different grown semiconductor layers. An extension of the first current blocking structure is interposed between the second current blocking structure and the waveguide current conduction region. Because each of the components is flanked by current confinement regions of differing structures, the resistive and capacitative properties of the current confinement regions can be selected to optimise the performance of that component for a particular use.

Abstract: An integrated buried heterojunction laser optically coupled to a ridge waveguide electro-absorption (EA) optical modulator having a raised ridge structure is manufactured on a single semiconductor substrate on which a plurality of semiconductor layers are grown, including at least one active layer through which optical radiation is coupled from the laser to the waveguide. Semiconductor layers above the active layer form a laser current conduction region and semiconductor layers adjacent the active layer form a laser current confinement region. The ridge structure is formed from one or more layers also used to form the laser current conduction region. The layers used to form the laser current confinement region do not extend adjacent the ridge structure.

Abstract: The present invention relates to solid state distributed feedback (DFB) lasers in which a phase shift is introduced to optical radiation circulating in a laser cavity in order to stabilise the laser into single mode operation. A solid state single mode distributed feedback (DFB) laser (1), comprises a laser waveguide (10), a DFB grating structure (6) optically coupled to the waveguide (10) for stabilising the wavelength of optical radiation (7) in the waveguide (10), one or more current conduction regions (4?, 4?) for guiding an applied electrical current to pump the laser waveguide (10) and at least one current constriction region (40) adjacent the one or more current conduction regions (4?, 4?). The DFB structure (6) extends in the current constriction region (40) and at least one of the current conduction regions (4?, 4?).

Abstract: A buried heterojunction laser optically coupled with a buried waveguide electro-absorption (EA) optical modulator via an active layer is fabricated on a substrate carrying a number of deposited semiconductor layers. The laser component includes a laser current conduction region and an adjacent laser current confinement region. The waveguide component includes a waveguide current confinement region comprising first and second current blocking structures formed from different grown semiconductor layers. An extension of the first current blocking structure is interposed between the second current blocking structure and the waveguide current conduction region. Because each of the components is flanked by current confinement regions of differing structures, the resistive and capacitative properties of the current confinement regions can be selected to optimise the performance of that component for a particular use.

Abstract: An integrated buried heterojunction laser optically coupled to a ridge waveguide electro-absorption (EA) optical modulator having a raised ridge structure is manufactured on a single semiconductor substrate on which a plurality of semiconductor layers are grown, including at least one active layer through which optical radiation is coupled from the laser to the waveguide. Semiconductor layers above the active layer form a laser current conduction region and semiconductor layers adjacent the active layer form a laser current confinement region. The ridge structure is formed from one or more layers also used to form the laser current conduction region. The layers used to form the laser current confinement region do not extend adjacent the ridge structure.

Abstract: The or each strained quantum well layer of a quantum confined Stark effect modulator is provided with a substructure of substructure layers not all having the same lattice constant. The thickness and composition of these substructure layers may be arranged to produce a differential strain that is asymmetric with respect to the mid-plane of the quantum well and so skews the hole wavefunctions for heavy-holes, HH1, and light-holes, LH1, in opposite directions. This enables the choice of composition designed to provide substantial matching of the E1-HH1 and E1-LH1 Stark shifts for one particular polarity of applied field, thereby providing a modulation facility that is substantially polarisation insensitive. Alternatively, the thickness and composition of the layers may be chosen to produce a symmetrical strain profile in which the same effect is provided, but for both polarities of applied field.