Abstract: Systems and methods for mapping location and characteristics about traffic participants are described. The systems and methods advantageously use correlative receivers for observing wireless emissions from or reflected by a plurality of traffic participants to allow for tracking geolocation and velocimetry information in real-time. The real-time geolocation and velocimetry information can be useful in autonomous vehicle navigation applications and useful for reducing computational burdens associated with tracking locations of many multiple traffic participants using direct sensor measurements, for example.

Abstract: Systems and methods for mapping location and characteristics about wireless emitters are described. The systems and methods advantageously use correlative receivers for observing the emissions from the wireless emitters without decrypting or decoding information included in the emissions from the wireless emitters to allow for tracking location and emitter class and type in real-time. The real-time geolocation and emitter class information for many receivers in a geographic area can be determined and overlaid on a map, for example.

Abstract: Various embodiments and methods relating to an optical fiber alignment and splicing system are described herein. The optical fiber alignment and splicing system includes a first rotation stage having a first central axis, a first end, and a second end, and a second rotation stage having a second central axis, a third end, and a fourth end. The first central axis extends from the first end to the second end of the first rotation stage, and the second central axis extends from the third end to the fourth end. The first rotation stage includes a first optical fiber channel extending from the first end of the first rotation stage to the second end of the first rotation stage, and the second rotation stage includes a second optical fiber channel extending from the third end of the second rotation stage to the fourth end of the second rotation stage.

Abstract: Various embodiments and methods related to an optical fiber alignment system are provided herein. The optical fiber alignment system includes a controller and a rotation stage having a central axis, a first end, and a second end. The central axis extends from the first end to the second end of the rotation stage. The rotation stage includes an optical fiber channel extending from the first end of the rotation stage to the second end of the rotation stage and may be operationally coupled with the controller. The rotation stage is configured to rotate about the central axis of the rotation stage. The optical fiber alignment system includes a light source positioned to emit light onto the optical fiber channel at an oblique angle from the central axis of the rotation stage. The optical fiber alignment system includes an image sensor positioned adjacent to the second end of the rotation stage.

Abstract: Various embodiments and method relating to an optical fiber curvature measurement system are described herein. The optical fiber curvature measurement system includes a controller and a rotation stage. The rotation stage includes a central axis, a first end, and a second end. The central axis extends from the first end to the second end of the rotation stage. The rotation stage includes an optical fiber channel extending from the first end of the rotation stage to the second end of the rotation stage. The rotation stage is operationally coupled with the controller and configured to rotate about the central axis of the rotation stage. An optical fiber may be positioned within the optical fiber channel. The optical fiber curvature measurement system also includes a light source positioned to emit light onto the optical fiber channel at an oblique angle from the central axis of the rotation stage.

Abstract: A system for determining the profile of a laser beam includes a detector having a thermochromic liquid crystal film (TLCF) in thermal communication with a heat spreader and a thermoelectric cooler. The liquid crystal film has a thermochromic response such that heating of the film by a received laser beam creates a detectable color response at the film. The system also includes an image sensor and a controller configured to output an operating current for the TEC and receive images from the sensor. The system can selectively vary the temperature set point of the TEC to change the steady state temperature of the TLCF to examine the full intensity profile of the received beam even when the temperature response bandwidth of the TLCF is too narrow to display the full beam profile in a single color spot.

Abstract: An apparatus includes a first antenna, a tunable optical carrier source, a second antenna, and a delay generation module coupled to the first antenna and the tunable optical carrier source. The apparatus also includes a fixed wavelength optical carrier source, an optical carrier generation module coupled to the fixed wavelength optical carrier source, and a local oscillator generation module. The apparatus further includes a correlative kernel generation and integration module coupled to the delay generation module and the local oscillator generation module and an optoelectronic conversion module coupled to the correlative kernel generation and integration module.

Abstract: An apparatus for generating a time-delayed product of two independent signals includes a fixed-wavelength laser. A first optical modulator is optically coupled to the fixed-wavelength laser and configured to modulate a fixed wavelength optical carrier with a first input signal of a set of input signals. The apparatus also includes a tunable laser. A second optical modulator is optically coupled to the tunable laser and configured to modulate a tunable optical carrier with a second input signal of the set of input signals. The apparatus also includes a dispersive element coupled to the second optical modulator, a first optical detector coupled to the dispersive element, a third optical modulator optically coupled to the first optical detector and the first optical modulator, an optical 90-degree hybrid element optically coupled to the third optical modulator, and a plurality of optical detectors optically coupled to the optical 90-degree hybrid element.

Abstract: A multi-wavelength laser system includes a first fiber laser having a first cavity mirror and a first output coupler, a first optical coupler configured to receive light from the first output coupler, a second fiber laser having a second cavity mirror and a second output coupler, and a second optical coupler configured to receive light from the second output coupler. The multi-wavelength laser system also includes a spectral beam combiner configured to receive first output light from the first optical coupler, receive second output light from the second optical coupler, combine the first output light and the second output light, and form a multi-wavelength output beam.

Abstract: A system for stabilizing optical parameters of a fiber Bragg grating (FBG) includes a mechanical mount, a heating element coupled to the mechanical mount, and a base plate coupled to the heating element. The base plate comprises a longitudinal groove. The system also includes a fiber anchor coupled to the mechanical mount and a fiber including the FBG mechanically attached to the fiber anchor. The FBG of the fiber is disposed in the longitudinal groove.

Abstract: A code acquisition module for a direct sequence spread spectrum (DSSS) receiver includes: a Sparse Discrete Fourier transform (SDFT) module configured to perform an SDFT on a finite number of non-uniformly distributed frequencies comprising a preamble of a received DSSS frame to calculate Fourier coefficients for the finite number of non-uniformly distributed frequencies; a multiplier configured to multiply the Fourier coefficients for the finite number of non-uniformly distributed frequencies of the received DSSS frame by complex conjugate Fourier coefficients for the finite number of non-uniformly distributed frequencies to generate a cross-correlation of the received DSSS frame and the complex conjugate Fourier coefficients; and a filter module configured to input the cross-correlation and output a delay estimation for the received DSSS frame.

Abstract: An apparatus for generating a set of spectral correlation coefficients of an input signal includes: a master laser configured to generate an optical frequency comb signal; a first optical modulator configured to modulate the optical frequency comb signal with an input signal to generate a plurality of spectral copies of the input signal; a dispersive element configured to delay the plurality of spectral copies of the input signal by a wavelength-dependent time delay; a second optical modulator configured to modulate the delayed plurality of spectral copies with a conjugate of the input signal; and an optical comb filter configured to integrate the conjugate modulated plurality of spectral copies of the input signal to generate a set of cyclic autocorrelation coefficients.

Abstract: An immersion grating includes a dielectric substrate having an incident light surface and a second surface opposing the incident light surface. The dielectric substrate is characterized by a substrate index of refraction. The immersion grating also includes at least one dielectric layer coupled to the second surface of the dielectric substrate. The at least one dielectric layer is characterized by a layer index of refraction greater than the substrate index of refraction. The immersion grating further includes a periodic structure formed in the at least one dielectric layer. The immersion grating is characterized by a diffraction efficiency greater than 99% over a wavelength range from 1041 nm to 1066 nm.

Abstract: A code acquisition module for a direct sequence spread spectrum (DSSS) receiver includes: a Sparse Discrete Fourier transform (SDFT) module configured to perform an SDFT on a finite number of non-uniformly distributed frequencies comprising a preamble of a received DSSS frame to calculate Fourier coefficients for the finite number of non-uniformly distributed frequencies; a multiplier configured to multiply the Fourier coefficients for the finite number of non-uniformly distributed frequencies of the received DSSS frame by complex conjugate Fourier coefficients for the finite number of non-uniformly distributed frequencies to generate a cross-correlation of the received DSSS frame and the complex conjugate Fourier coefficients; and a filter module configured to input the cross-correlation and output a delay estimation for the received DSSS frame.

Abstract: An apparatus for generating a set of spectral correlation coefficients of an input signal includes: a master laser configured to generate an optical frequency comb signal; a first optical modulator configured to modulate the optical frequency comb signal with an input signal to generate a plurality of spectral copies of the input signal; a dispersive element configured to delay the plurality of spectral copies of the input signal by a wavelength-dependent time delay; a second optical modulator configured to modulate the delayed plurality of spectral copies with a conjugate of the input signal; and an optical comb filter configured to integrate the conjugate modulated plurality of spectral copies of the input signal to generate a set of cyclic autocorrelation coefficients.

Abstract: A spectral beam combining system includes a plurality of input fibers and a prism having a curved input surface. The plurality of input fibers are attached to the curved input surface. The spectral beam combining system also includes an immersion grating defined on a second surface of the prism, a protective cap disposed over the immersion grating, and an output surface.

Abstract: A code acquisition module for a direct sequence spread spectrum (DSSS) receiver includes: a Sparse Discrete Fourier transform (SDFT) module configured to perform an SDFT on a finite number of non-uniformly distributed frequencies comprising a preamble of a received DSSS frame to calculate Fourier coefficients for the finite number of non-uniformly distributed frequencies; a multiplier configured to multiply the Fourier coefficients for the finite number of non-uniformly distributed frequencies of the received DSSS frame by complex conjugate Fourier coefficients for the finite number of non-uniformly distributed frequencies to generate a cross-correlation of the received DSSS frame and the complex conjugate Fourier coefficients; and a filter module configured to input the cross-correlation and output a delay estimation for the received DSSS frame.

Abstract: A spectral beam combining system includes a plurality of input fibers and a prism having a curved input surface. The plurality of input fibers are attached to the curved input surface. The spectral beam combining system also includes an immersion grating defined on a second surface of the prism, a protective cap disposed over the immersion grating, and an output surface.

Abstract: A code acquisition module for a direct sequence spread spectrum (DSSS) receiver includes: a Sparse Discrete Fourier transform (SDFT) module configured to perform an SDFT on a finite number of non-uniformly distributed frequencies comprising a preamble of a received DSSS frame to calculate Fourier coefficients for the finite number of non-uniformly distributed frequencies; a multiplier configured to multiply the Fourier coefficients for the finite number of non-uniformly distributed frequencies of the received DSSS frame by complex conjugate Fourier coefficients for the finite number of non-uniformly distributed frequencies to generate a cross-correlation of the received DSSS frame and the complex conjugate Fourier coefficients; and a filter module configured to input the cross-correlation and output a delay estimation for the received DSSS frame.

Abstract: A code acquisition module for a direct sequence spread spectrum (DSSS) receiver includes: a Sparse Discrete Fourier transform (SDFT) module configured to perform an SDFT on a finite number of non-uniformly distributed frequencies comprising a preamble of a received DSSS frame to calculate Fourier coefficients for the finite number of non-uniformly distributed frequencies; a multiplier configured to multiply the Fourier coefficients for the finite number of non-uniformly distributed frequencies of the received DSSS frame by complex conjugate Fourier coefficients for the finite number of non-uniformly distributed frequencies to generate a cross-correlation of the received DSSS frame and the complex conjugate Fourier coefficients; and a filter module configured to input the cross-correlation and output a delay estimation for the received DSSS frame.