Abstract: A transmitter generates a first electrical signal comprising a first low-frequency signal, an empty period, and a pump pulse having a first frequency; and a second electrical signal comprising a second low-frequency signal and at least two probe pulses, each probe pulse having a second frequency that differs from the first frequency. The transmitter modulates first and second optical subcarriers having different polarizations using the first and second electrical signals, respectively. The transmitter generates an optical signal from the first and second optical subcarriers, wherein the first and second low-frequency signals overlap in time, wherein the empty period overlaps in time with one of the probe pulses, and wherein the pump pulse overlaps in time with another one of the probe pulses. The optical signal is detected at a receiver over an optical link, and the receiver uses the optical signal to estimate nonlinear phase shift in the optical link.

Abstract: A transmitter generates a first electrical signal comprising a first low-frequency signal, an empty period, and a pump pulse having a first frequency; and a second electrical signal comprising a second low-frequency signal and at least two probe pulses, each probe pulse having a second frequency that differs from the first frequency. The transmitter modulates first and second optical subcarriers having different polarizations using the first and second electrical signals, respectively. The transmitter generates an optical signal from the first and second optical subcarriers, wherein the first and second low-frequency signals overlap in time, wherein the empty period overlaps in time with one of the probe pulses, and wherein the pump pulse overlaps in time with another one of the probe pulses. The optical signal is detected at a receiver over an optical link, and the receiver uses the optical signal to estimate nonlinear phase shift in the optical link.

Abstract: A transmitter generates a first electrical signal comprising a first low-frequency signal, an empty period, and a pump pulse having a first frequency; and a second electrical signal comprising a second low-frequency signal and at least two probe pulses, each probe pulse having a second frequency that differs from the first frequency. The transmitter modulates first and second optical subcarriers having different polarizations using the first and second electrical signals, respectively. The transmitter generates an optical signal from the first and second optical subcarriers, wherein the first and second low-frequency signals overlap in time, wherein the empty period overlaps in time with one of the probe pulses, and wherein the pump pulse overlaps in time with another one of the probe pulses. The optical signal is detected at a receiver over an optical link, and the receiver uses the optical signal to estimate nonlinear phase shift in the optical link.

Abstract: A transmitter generates a first electrical signal comprising a first low-frequency signal, an empty period, and a pump pulse having a first frequency; and a second electrical signal comprising a second low-frequency signal and at least two probe pulses, each probe pulse having a second frequency that differs from the first frequency. The transmitter modulates first and second optical subcarriers having different polarizations using the first and second electrical signals, respectively. The transmitter generates an optical signal from the first and second optical subcarriers, wherein the first and second low-frequency signals overlap in time, wherein the empty period overlaps in time with one of the probe pulses, and wherein the pump pulse overlaps in time with another one of the probe pulses. The optical signal is detected at a receiver over an optical link, and the receiver uses the optical signal to estimate nonlinear phase shift in the optical link.

Abstract: The present invention uses digital subcarrier cross-connect switching to accomplish various network processes more efficiently. These processes include interconnecting network components, and performing optical and optoelectronic add/drop operations.

Abstract: A low-altitude altimeter (10) and a method of determining low altitudes for unmanned aerial vehicles (24). The altimeter includes at least two illuminators (12, 14), at least one sensor (16), and a computing device (18). The illuminators (12, 14) emit signals which are received by the sensor (16) in such a way that an angle at which they are received is determinable by the computing device (18). The computing device (18) processes each signal received by the sensor (16), determines the angle at which the sensor (16) received the signal, and, based thereon, determines the altitude of the unmanned aerial vehicle (24). When a first pair of illuminators are arranged along a fuselage axis, and a second pair of illuminators are arranged orthogonally to that axis, the computing device can combine first and second altitude, pitch angle, and roll angle measurements to provide a more refined altitude determination.

Abstract: A low-altitude altimeter (10) and a method of determining low altitudes for unmanned aerial vehicles (24). The altimeter includes at least two illuminators (12, 14), at least one sensor (16), and a computing device (18). The illuminators (12, 14) emit signals which are received by the sensor (16) in such a way that an angle at which they are received is determinable by the computing device (18). The computing device (18) processes each signal received by the sensor (16), determines the angle at which the sensor (16) received the signal, and, based thereon, determines the altitude of the unmanned aerial vehicle (24). When a first pair of illuminators are arranged along a fuselage axis, and a second pair of illuminators are arranged orthogonally to that axis, the computing device can combine first and second altitude, pitch angle, and roll angle measurements to provide a more refined altitude determination.

Abstract: A low-altitude altimeter (10) and a method of determining low altitudes for unmanned aerial vehicles (24). The altimeter includes at least two illuminators (12,14), at least one sensor (16), and a computing device (18). The illuminators (12,14) emit signals which are received by the sensor (16) in such a way that an angle at which they are received is determinable by the computing device (18). The computing device (18) processes each signal received by the sensor (16), determines the angle at which the sensor (16) received the signal, and, based thereon, determines the altitude of the unmanned aerial vehicle (24). When a first pair of illuminators are arranged along a fuselage axis, and a second pair of illuminators are arranged orthogonally to that axis, the computing device can combine first and second altitude, pitch angle, and roll angle measurements to provide a more refined altitude determination.

Abstract: The present invention uses digital subcarrier cross-connect switching to accomplish various network processes more efficiently. These processes include interconnecting network components, and performing optical and optoelectronic add/drop operations.

Abstract: A low-altitude altimeter (10) and a method of determining low altitudes for unmanned aerial vehicles (24). The altimeter includes at least two illuminators (12,14), at least one sensor (16), and a computing device (18). The illuminators (12,14) emit signals which are received by the sensor (16) in such a way that an angle at which they are received is determinable by the computing device (18). The computing device (18) processes each signal received by the sensor (16), determines the angle at which the sensor (16) received the signal, and, based thereon, determines the altitude of the unmanned aerial vehicle (24). When a first pair of illuminators are arranged along a fuselage axis, and a second pair of illuminators are arranged orthogonally to that axis, the computing device can combine first and second altitude, pitch angle, and roll angle measurements to provide a more refined altitude determination.

Abstract: A mobile target screen is described for ball game practicing and simulation. Tow force sensors are mounted at each of the four corners of the frame which holds a target screen. Measurements form the force sensors are used to compute and display a representation of ball speed, the location of the ball on the target screen, and the direction of the ball motion. These parameters can be used to predict the shooting distance and the landing position of the ball. It also provides enough information to predict the trajectory of the ball which can be displayed on a video screen which communicates with the sensors through a wireless transceiver.

Abstract: A method is provided for measuring polarization dependent loss in an optical transmission system. In the method, a first optical signal is generated, and a polarization of the first optical signal is altered over time. The first optical signal is combined with a second optical signal from the optical transmission system to yield a combined optical signal, which is coherently detected to yield a radio frequency signal. A power of the radio frequency signal is measured. The measured power of the radio frequency signal is processed to generate an indication of the polarization dependent loss of the optical transmission system.

Abstract: An optical homodyne detection scheme for FM chirped lidar is described. The system performs de-chirping within a photodetector, and it does not require high-speed photo-detection or RF mixing. Embodiments are also described for dealing with phase noise.

Abstract: The present disclosure relates to the use of III-nitride wide bandgap semiconductor materials for optical communications. In one embodiment, an optical device includes an optical waveguide device fabricated using a III-nitride semiconductor material. The III-nitride semiconductor material provides for an electrically controllable refractive index. The optical waveguide device provides for high speed optical communications in an infrared wavelength region. In one embodiment, an optical amplifier is provided using optical coatings at the facet ends of a waveguide formed of erbium-doped III-nitride semiconductor materials.

Abstract: An optical homodyne detection scheme for FM chirped lidar is described. The system performs de-chirping within a photodetector, and it does not require high-speed photo-detection or RF mixing. Embodiments are also described for dealing with phase noise.

Abstract: A laser system (10) for use in photonic excitation investigation of a target object, in which the target object interacts with incident photons and emits a corresponding photon which is detected and used to generate an image of the target object. The laser system (10) includes a pulsed fiber laser (14) for producing a laser beam, and a non-linear photonic crystal fiber (16) for carrying the laser beam from the laser (14) to an instrument (18) for photonically exciting the target object. The photonic crystal fiber (16) allows for switching, or tuning, the wavelength of the laser beam. In two-photon microscopy, the laser system (10) allows for providing multiple wavelengths for exciting a plurality of different fluorophores simultaneously. In coherent Raman imaging and spectroscopy, the laser system (110) allows for using a single laser to provide two laser beams of different wavelengths.

Abstract: A receiver system processes a received optical signal that carries user information. The receiver system includes a splitter, a first converter, a second converter, and a detection system. The splitter splits the received optical signal based on polarization into a first optical signal and a second optical signal. The first converter converts the first optical signal into a corresponding first electrical signal. The second converter also converts the second optical signal into a corresponding second electrical signal. The detection system applies radio frequency detection to the first electrical signal to generate a third electrical signal. The detection system applies radio frequency detection to the second electrical signal to generate a fourth electrical signal. The detection system then combines the third electrical signal and the fourth electrical signal to form a fifth electrical signal that carries the user information.

Abstract: The present disclosure relates to the use of III-nitride wide bandgap semiconductor materials for optical communications. In one embodiment, an optical device includes an optical waveguide device fabricated using a III-nitride semiconductor material. The III-nitride semiconductor material provides for an electrically controllable refractive index. The optical waveguide device provides for high speed optical communications in an infrared wavelength region. In one embodiment, an optical amplifier is provided using optical coatings at the facet ends of a waveguide formed of erbium-doped III-nitride semiconductor materials.

Abstract: An Optical Domain Signal Analyzer, having an optical filter, a dispersive element and a detector is utilized to provide high resolution spectrum analysis over a wide optical bandwidth. The optical domain signal analyzer broadly includes an optical filter for providing wavelength samples of a received optical signal, a dispersive element for receiving the samples and dispersing the samples, and a detector for receiving the dispersed signal and for providing electrical signals representative of the dispersed sample. A preferred embodiment includes a processor for receiving the electrical signal and calculating the characteristics of the spectrum.

Abstract: The present invention provides a method and apparatus for monitoring optical signals with an expanded frequency resolution. The invention permits high-resolution measurements of optical signal spectrums while retaining wide bandwidth operation through appropriate control circuitry. An interferometer having a periodic frequency response formed of equally spaced narrow-band peaks is used to sweep the entire signal spectrum. The interferometer frequency response is incrementally tuned in cycles so that each of its frequency response peaks cyclically scans a particular spectral band of the signal spectrum. During each cycle, the interferometer isolates multiple spectrally resolved portions of the optical signal spectrum where each portion originates from a different spectral band. In this way, a high-resolution measurement of the entire signal spectrum can be obtained. The invention may be network protocol independent and can be incorporated into an optical spectrum analyzer or directly into any optical terminal.