Abstract: A method and system for remote sensing. The method includes applying an orbital angular momentum (OAM) mode on a light beam to generate an OAM light beam having an optical OAM spectrum, exposing a target object to the OAM light beam such that the target object absorbs energy of the OAM light beam to generate ultrasonic emissions, the ultrasonic emissions having a reflected OAM spectrum associated with the target object, and generating a high resolution image of the target object based on the reflected OAM spectrum.

Abstract: Systems and methods for detection of atmospheric conditions using optical orbital angular momentum (OAM)-based spectroscopy include applying OAM states to a light beam to generate an OAM spectrum, transmitting OAM light beams into an atmosphere, and determining degradation of the generated OAM light beams passing through atmospheric turbulence. A rotation rate of aerosols in the atmosphere is determined by analyzing different frequency shifts in OAM states of OAM light beams. A reflected OAM spectrum including a plurality of OAM light beams associated with the aerosols in the atmosphere may be received, and Doppler frequency shifts caused by reflection off the aerosols in the atmosphere may be measured. Laguerre-Gaussian (LG) modes of the received light beams may be detected and sorted based on the OAM states of the LG modes, and wind turbulence values are predicted by analyzing a difference in the Doppler frequency shifts for the received OAM light beams.

Abstract: A method and system are provided. The method includes converting, using a spatial mode converter, an input signal into a plurality of spatial modes and performing polarization multiplexing and mode multiplexing, using a polarization multiplexer and a mode multiplexer, respectively, on the input signal. The method further includes injecting the input signal into a fiber optic medium. The method additionally includes applying, using at least one spatial filter in each of a forward and a backward direction within the fiber optic medium, the plurality of spatial modes within the fiber optic medium to transmit the input signal and perform distributed fault sensing on the input signal simultaneously.

Abstract: A sensor system includes a femtosecond infrared (fs-IR) laser to generate a laser beam; a reflecting mirror optically receiving the laser beam; a lens optically coupled to the reflecting mirror to focus the laser beam; a phase mask receiving the laser beam from the lens to generate an index modulated pattern; and a few-mode fiber (FMF) receiving the index modulated pattern.

Abstract: Methods and systems for sensing conditions of a fiber include splitting a light signal into two branches. A first branch is converted to have a mode different from that of the second branch. Both branches are mode multiplexed into a single fiber. An output of the fiber is mode demultiplexed into the two branches. The first branch is mode converted to its original mode. Brillouin scattering patterns of the two branches are compared to determine a temperature and strain profile of the fiber.

Abstract: A method and system for optical angular momentum (OAM) spectroscopy includes generating a beam of light having a single OAM mode. A first spectrum of the beam of light is detected and the beam of light is passed through a gas to attenuate the beam of light in accordance with a presence and concentration of a respective gas. A second spectrum the beam of light is coherently detected and a difference between the first and second spectrum for the beam of light is analyzed to determine the presence and concentration of the respective gas.

Abstract: A sensor system includes a femtosecond infrared (fs-IR) laser to generate a laser beam; a reflecting mirror optically receiving the laser beam; a lens optically coupled to the reflecting mirror to focus the laser beam; a phase mask receiving the laser beam from the lens to generate an index modulated pattern; and a few-mode fiber (FMF) receiving the index modulated pattern.

Abstract: Methods and systems of sensing conditions in a fiber includes launching a light beam into a fiber. A first branch of scattered light is set to a mode other than a fundamental mode. A second branch of scattered light is optically filtered to remove unscattered input light. Brillouin scattered light is coherently detected on the first branch to produce a combined temperature/strain profile of the fiber. Raman scattered light on the second branch is directly detected to produce a temperature profile of the fiber. A strain profile of the fiber is determined, using a processor, based on the combined temperature/strain profile and the temperature profile.

Abstract: Systems and methods for detection of atmospheric conditions using optical orbital angular momentum (OAM)-based spectroscopy include applying OAM states to a light beam to generate an OAM spectrum, transmitting OAM light beams into an atmosphere, and determining degradation of the generated OAM light beams passing through atmospheric turbulence. A rotation rate of aerosols in the atmosphere is determined by analyzing different frequency shifts in OAM states of OAM light beams. A reflected OAM spectrum including a plurality of OAM light beams associated with the aerosols in the atmosphere may be received, and Doppler frequency shifts caused by reflection off the aerosols in the atmosphere may be measured. Laguerre-Gaussian (LG) modes of the received light beams may be detected and sorted based on the OAM states of the LG modes, and wind turbulence values are predicted by analyzing a difference in the Doppler frequency shifts for the received OAM light beams.

Abstract: Systems and methods are disclosed for sensing acceleration or vibration of a physical object, by placing a two-mode elliptical-core optical fiber on the object; receiving optical signals using photo-detector; and determining acceleration as perturbation effects on the differential phase shift between two spatial modes in each polarization or between two polarization modes in each spatial mode for the two-mode elliptical-core optical fiber.

Abstract: A method and system for remote sensing. The method includes applying an orbital angular momentum (OAM) mode on a light beam to generate an OAM light beam having an optical OAM spectrum, exposing a target object to the OAM light beam such that the target object absorbs energy of the OAM light beam to generate ultrasonic emissions, the ultrasonic emissions having a reflected OAM spectrum associated with the target object, and generating a high resolution image of the target object based on the reflected OAM spectrum.

Abstract: A method and system are provided. The method includes converting, using a spatial mode converter, an input signal into a plurality of spatial modes and performing polarization multiplexing and mode multiplexing, using a polarization multiplexer and a mode multiplexer, respectively, on the input signal. The method further includes injecting the input signal into a fiber optic medium.

Abstract: Methods and systems of sensing conditions in a fiber includes launching a light beam into a fiber. A first branch of scattered light is set to a mode other than a fundamental mode. A second branch of scattered light is optically filtered to remove unscattered input light. Brillouin scattered light is coherently detected on the first branch to produce a combined temperature/strain profile of the fiber. Raman scattered light on the second branch is directly detected to produce a temperature profile of the fiber. A strain profile of the fiber is determined, using a processor, based on the combined temperature/strain profile and the temperature profile.

Abstract: A method and system for optical angular momentum (OAM) spectroscopy includes generating a beam of light having a single OAM mode. A first spectrum of the beam of light is detected and the beam of light is passed through a gas to attenuate the beam of light in accordance with a presence and concentration of a respective gas. A second spectrum the beam of light is coherently detected and a difference between the first and second spectrum for the beam of light is analyzed to determine the presence and concentration of the respective gas.

Abstract: Methods and systems for sensing conditions of a fiber include splitting a light signal into two branches. A first branch is converted to have a mode different from that of the second branch. Both branches are mode multiplexed into a single fiber. An output of the fiber is mode demultiplexed into the two branches. The first branch is mode converted to its original mode. Brillouin scattering patterns of the two branches are compared to determine a temperature and strain profile of the fiber.

Abstract: A system and method is provided for improved and efficient decoding of a received data sequence. The invention can perform the decoding using a LogMap function for a set of N inputs, where N is greater than 2.

Abstract: A system and method is provided for improved and efficient forward and backward recursive computations that may be used, for example, with turbo code decoding applications. The invention performs the forward computations using a full length of a sequence to be decoded and performs the reverse computations using a sliding window over the sequence.

Abstract: A system and method is provided for improved and efficient forward and backward recursive computations that may be used, for example, with turbo code decoding applications. The invention performs the forward computations using a full length of a sequence to be decoded and performs the reverse computations using a sliding window over the sequence.

Abstract: A multiple stage matched filter for a wireless receiver comprises a receiver configured to develop a received signal, the received signal comprising a bit stream of signal samples, and a multiple stage matched filter configured to parallel process the received signal such that multiple codes are analyzed simultaneously to determine a frequency offset and code location.

Abstract: A system and method is provided for improved and efficient forward and backward recursive computations that may be used, for example, with turbo code decoding applications. The invention performs the forward computations using a full length of a sequence to be decoded and performs the reverse computations using a sliding window over the sequence.