Abstract: A wavelength assignment system in one embodiment includes an upstream port, a sensor port, and a downstream port. The upstream port is configured to receive a transmitted signal including a drive component and a read component comprising individual read channel components at corresponding individual read wavelengths. The sensor port is configured to provide a sensor component of the transmitted signal including a sensor portion of the drive component and substantially all of an individual read channel component to a sensor. The downstream port is configured to provide a downstream component including a downstream portion of the drive component and at least one additional read channel component of the transmitted signal to at least one additional sensor disposed downstream of the sensor. The wavelength assignment system is configured to receive the transmitted signal and separate the transmitted signal into the sensor component and the downstream component.

Abstract: A pressure sensing cable in one embodiment includes an optical fiber having a first core and a second core. The first core extends along a length of the cable, and is sized and configured to provide propagation of light along the first core along the length of the cable. The first core has a first mode index corresponding to the speed of light propagation along the first core. The second core extends along the length, is spaced a distance from the first core, and is sized and configured to provide propagation of light along the second core along the length of the cable. The second core has a second mode index corresponding to the speed of light propagation along the second core. The second mode index is different from the first mode index, wherein light propagates along the second core at a different speed than along the first core.

Abstract: A pressure sensing cable in one embodiment includes an optical fiber having a first core and a second core. The first core extends along a length of the cable, and is sized and configured to provide propagation of light along the first core along the length of the cable. The first core has a first mode index corresponding to the speed of light propagation along the first core. The second core extends along the length, is spaced a distance from the first core, and is sized and configured to provide propagation of light along the second core along the length of the cable. The second core has a second mode index corresponding to the speed of light propagation along the second core. The second mode index is different from the first mode index, wherein light propagates along the second core at a different speed than along the first core.

Abstract: A wavelength assignment system in one embodiment includes an upstream port, a sensor port, and a downstream port. The upstream port is configured to receive a transmitted signal including a drive component and a read component comprising individual read channel components at corresponding individual read wavelengths. The sensor port is configured to provide a sensor component of the transmitted signal including a sensor portion of the drive component and substantially all of an individual read channel component to a sensor. The downstream port is configured to provide a downstream component including a downstream portion of the drive component and at least one additional read channel component of the transmitted signal to at least one additional sensor disposed downstream of the sensor. The wavelength assignment system is configured to receive the transmitted signal and separate the transmitted signal into the sensor component and the downstream component.

Abstract: A sensor interrogation unit in one embodiment includes a control module, a reading module, and a determination module. The control module is configured to control one or more lasers to provide a pulsed signal to at least one sensor. Each period of the pulsed signal has a first component having a first intensity and a second component having a second intensity that is lower than the first intensity. The reading module is configured to receive at least one return signal comprising reflections of the pulsed signal from the at least one sensor, to read one of the first component or the second component, and to provide frequency information based on the read reflections. The determination module is configured to determine at least one resonant frequency of the at least one sensor based on the frequency information.

Abstract: A pressure sensing cable in one embodiment includes a polarization maintaining (PM) optic fiber having a length; and a Fiber Bragg Grating (FBG) pair formed in the PM optic fiber. The FBG pair includes a first FBG formed at a location along the length of the optic fiber. The first FBG defines a first wavelength range at which the first FBG is reflective. The FBG pair also includes a second FBG spaced a distance from the first FBG to define a FBG cavity extending between the first FBG and the second FBG. The second FBG defines a second wavelength range at which the second FBG is reflective. The first wavelength range of the first FBG and the second wavelength range of the second FBG at least partially overlap.

Abstract: A system for optically monitoring a gas turbine engine includes an optical multiplexer configured to receive multiple images from respective viewports into the gas turbine engine. The optical multiplexer includes a movable reflective device configured to selectively direct at least a portion of each image toward a detector array, and the detector array is directed toward a fixed location on the optical multiplexer.

Abstract: A magnetic recording apparatus includes a write element and an optical device for heating a portion of a magnetic medium. The optical device and the write element are arranged to generally prevent the write element from affecting the optical fields generated by the optical device.

Abstract: A measurement system in one embodiment includes an acquisition module and a determination module. The acquisition module is configured to acquire resonant frequency information corresponding to a sensor disposed in a remote location from the acquisition module. The resonant frequency information includes first resonant frequency information for a first resonant frequency of the sensor corresponding to environmental conditions of the remote location, and also includes second resonant frequency information for a different, second resonant frequency of the sensor corresponding to the environmental conditions of the remote location. The determination module is configured to use the first resonant frequency information and the second resonant frequency information to determine the temperature and the pressure at the remote location.

Abstract: An apparatus including a near field transducer positioned adjacent to an air bearing surface, the near field transducer comprising silver (Ag) and at least one other element or compound; a first magnetic pole; and a heat sink positioned between the first magnetic pole and the near field transducer, wherein the heat sink includes: rhodium (Rh) or an alloy thereof; ruthenium (Ru) or an alloy thereof; titanium (Ti) or an alloy thereof; tantalum (Ta) or an alloy thereof; tungsten (W) or an alloy thereof; borides; nitrides; transition metal oxides; or palladium (Pd) or an alloy thereof.

Abstract: A system for optically monitoring a gas turbine engine includes an optical multiplexer configured to receive multiple images from respective viewports into the gas turbine engine. The optical multiplexer includes a movable reflective device configured to selectively direct at least a portion of each image toward a detector array, and the detector array is directed toward a fixed location on the optical multiplexer.

Abstract: A system for optically monitoring a gas turbine engine includes a viewport having an opening disposed within a casing of the gas turbine engine. The opening extends from an interior side of the casing to an exterior side of the casing, and the viewport is configured to receive an image from inside the casing. The system also includes an optical connection positioned outside the casing and optically coupled to the viewport. The optical connection is configured to convey the image from the viewport to a detector array, and the optical connection includes multiple optical fibers fused to one another to form a unitary substantially rigid fiber bundle.

Abstract: An apparatus including a near field transducer positioned adjacent to an air bearing surface, the near field transducer including an electrically conductive nitride; a first magnetic pole; and a heat sink, a diffusion barrier layer, or both positioned between the first magnetic pole and the near field transducer, wherein the heat sink, the diffusion barrier or both include rhodium (Rh) or an alloy thereof; ruthenium (Ru) or an alloy thereof titanium (Ti) or an alloy thereof tantalum (Ta) or an alloy thereof tungsten (W) or an alloy thereof borides; nitrides; transition metal oxides; or palladium (Pd) or an alloy thereof.

Abstract: An apparatus includes a write pole, a waveguide adjacent to the write pole, the waveguide having a truncated end, and a blocking layer positioned adjacent the truncated end and extending from one side of the waveguide across a portion of an aperture at the truncated end. The waveguide can be a solid immersion mirror or a channel waveguide.

Abstract: Optical-based apparatus and method for sensing parameters in connection with an asset, such as a pipeline, are provided. At least two sites in an optical fiber may include a respective fiber grating arranged to have a respective optical response in a wavelength spectrum having a distinguishing feature indicative of a value of a respective local parameter at a respective grating site. The two fiber gratings may be further arranged to form, in combination with a respective portion of the optical fiber which extends between the two sites, respective optical backscatter portions that when combined with one another are effective to sense an optical change in the fiber portion between the sites indicative of a value of a distributed parameter. This is a parameter modality different from a parameter modality of the respective local parameters at the respective grating sites.

Abstract: An apparatus includes a near field transducer positioned adjacent to an air bearing surface, a first magnetic pole, a heat sink positioned between the first magnetic pole and the near field transducer, and a diffusion barrier positioned between the near field transducer and the first magnetic pole. The diffusion barrier can be positioned adjacent to the magnetic pole or the near field transducer.

Abstract: An apparatus including a near field transducer positioned adjacent to an air bearing surface, the near field transducer comprising silver (Ag) and at least one other element or compound; a first magnetic pole; and a heat sink positioned between the first magnetic pole and the near field transducer, wherein the heat sink includes: rhodium (Rh) or an alloy thereof; ruthenium (Ru) or an alloy thereof; titanium (Ti) or an alloy thereof; tantalum (Ta) or an alloy thereof; tungsten (W) or an alloy thereof; borides; nitrides; transition metal oxides; or palladium (Pd) or an alloy thereof.

Abstract: An apparatus including a near field transducer positioned adjacent to an air bearing surface, the near field transducer including an electrically conductive nitride; a first magnetic pole; and a heat sink, a diffusion barrier layer, or both positioned between the first magnetic pole and the near field transducer, wherein the heat sink, the diffusion barrier or both include rhodium (Rh) or an alloy thereof; ruthenium (Ru) or an alloy thereof titanium (Ti) or an alloy thereof tantalum (Ta) or an alloy thereof tungsten (W) or an alloy thereof borides; nitrides; transition metal oxides; or palladium (Pd) or an alloy thereof.

Abstract: A near field transducer antenna has a first end proximate a media writing surface and a second end proximate a waveguide that delivers light to the antenna. The antenna includes an aperture disposed along a propagation axis that extends from the first end to the second end. A notch protrudes within the aperture. The notch is facing an opening of the aperture that extends along the propagation axis. A magnetic pole is proximate the antenna, and includes a first portion of magnetic material and a second portion of antenna material. The second portion is disposed over the opening of the aperture and facing the notch of the antenna.

Abstract: A near field transducer antenna has a first end proximate a media writing surface and a second end proximate a waveguide that delivers light to the antenna. The antenna includes an aperture disposed along a propagation axis that extends from the first end to the second end. A notch protrudes within the aperture. The notch is facing an opening of the aperture that extends along the propagation axis. A magnetic pole is proximate the antenna, and includes a first portion of magnetic material and a second portion of antenna material. The second portion is disposed over the opening of the aperture and facing the notch of the antenna.