Abstract: Example embodiments disclose a tunable optical pair source (TOPS) configured to generate first and second output optical beams having respective first and second frequencies that are phase locked with each other. The TOPS may include a first laser, such as a tunable laser, configured to generate a first laser beam, a radio frequency (RF) oscillator configured to transmit an RF reference signal, a beam splitter in optical communication with the first laser, and an electro-optic modulator configured to modulate the second split beam with the RF reference signal to form a modulated beam having a first sideband comb comprising a plurality of harmonics. Additionally, the TOPS may include an optical filter configured to receive the modulated beam and output a filtered optical beam, and a second laser configured to generate a second laser beam at the second frequency, the second laser being configured to receive the filtered optical beam as a seed.

Abstract: An transmitter to be used in wireless multi-user MIMO has been described above. The system combines the virtues of digital, analog and optical processing to arrive at a solution for scalable, non-blocking, simultaneous transmission to multiple UE-s. The system architecture is independent of the RF carrier frequency, and different frequency bands can be accessed easily and rapidly by tuning the optical source (TOPS). The data channels are established in the digital domain and the RF beam-forming accuracy is only limited by the available resolution of DAC, which can be as high as 16 bits for 2.8 GSPS in off-the-shelf components.

Abstract: A hyperspectral radiometer may comprise one or more antennas, a electro-optical modulator modulating the received RF signal onto an optical carrier to generate a modulated signal having at least one sideband; a filter filtering the modulated signal to pass the sideband to a photodetector; and a photodetector producing an electrical signal from which information of the RF signal can be extracted. In some examples, the optical sideband may be spatially dispersed to provide a plurality of spatially separate optical components to the photodetector, where the spatially separate optical components having different frequencies and correspond to different frequencies of the received RF signal. In some examples, the passed sideband may be mixed with an optical beam having a frequency offset from the optical carrier to form a combined beam having at least one optical signal component having a beat frequency from which information of the RF signal can be extracted.

Abstract: This disclosure is directed to two-dimensional conformal optically-fed phased arrays and methods for manufacturing the same. The method includes providing a wafer substrate, depositing a first cladding layer on the wafer substrate, and depositing a core layer on the first cladding layer. The method further includes photolithographically patterning the core layer to provide a plurality of optical waveguide cores, and depositing a second cladding layer on the core layer to cover the plurality of optical waveguide cores to provide a plurality of optical waveguides. In addition, the method includes forming a plurality of antennas on the second cladding layer, each antenna of the plurality of antennas located near a termination of a corresponding optical waveguide of the plurality of optical waveguides, and providing a plurality of photodiodes on the second cladding layer, each photodiode of the plurality of photodiodes connected to a corresponding antenna.

Abstract: An optical imaging system and method that reconstructs RF sources in k-space by utilizing interference amongst modulated optical beams. The system and method involves recording with photodetectors the interference pattern produced by RF-modulated optical beams conveyed by optical fibers having unequal lengths. The photodetectors record the interference, and computational analysis using known tomography reconstruction methods is performed to reconstruct the RF sources in k-space.

Abstract: A system and method reconstructs RF sources in k-space by utilizing interference between RF signals detected by an array of antennas. The system and method may include detecting an RF interference pattern resulting from interference between RF signals in an RF coupler, where the RF signals are detected by the antennas and provided to the RF coupler by RF waveguides. The RF waveguides may have unequal RF path lengths. K-space information of the RF sources may be reconstructed from the detected RF interference pattern using known tomography reconstruction methods.

Abstract: A method and apparatus for simultaneously modulating at least two distinct characteristics of an optical carrier propagating in an optical waveguide with at least two electrical signals includes transmitting an optical beam that includes the optical carrier into an optical waveguide defined in electro-optic material, and applying the at least two electrical signals at the same time to generate an electric field in the optical waveguide. The instantaneous predominant orientation of the electric field in the optical waveguide generated by the applied at least two electrical signals depends on the relative instantaneous values of the applied electrical signals. The at least two distinct characteristics of the optical carrier propagating in the optical waveguide are simultaneously and independently modulated depending on the predominant orientation of the electric field in the optical waveguide as a result of the application of the at least two electrical signals.

Abstract: A photodiode device and method of manufacturing the same are disclosed. A stack of functional layers of the photodiode device, formed of crystalline semiconductor material, may be formed on a diamond substrate. The stack of functional layers may be in contact with or close proximity to the diamond substrate to thereby provide an efficient thermal conductive path between the functional layers and an external source, thereby mitigating problems that may result from overheating the photodiode device.

Abstract: A vehicle such as a helicopter may scan a scene using a transmitter mounted on a rotating part like a rotor and a receiver mounted on a body of the vehicle. Based on a Doppler shift caused by the rotation of the rotating part, patterns may be recorded and used to develop a holographic image of the scene.

Abstract: A phased antenna array comprises a plurality of antennas and photodiodes arranged on a substrate. Each antenna is driven by an electrical signal output by the photodiode. The photodiodes each receive an optical signal via an optical fiber. The optical fibers conform to the sheet-like shape of the antenna array (which may be planar or curved) and optically communicate with a corresponding photodiode via a corresponding reflector, such as a ninety degree reflector. The reflectors may comprise a v-groove in a silicon substrate on which the optical fiber is positioned and a reflecting surface. Each reflector may be attached to the substrate or a ground plane positioned parallel to the substrate and the optical fiber may connect to the reflector in a direction running parallel to the phased antenna array. This optical feed network may accommodate tight spacing of the antenna elements (such as spacing less than 5 mm apart) with a thin profile.

Abstract: A method of RF signal processing comprises receiving an incoming RF signal at each of a plurality of antenna elements that are arranged in a first pattern. The received RF signals from each of the plurality of antenna elements are modulated onto an optical carrier to generate a plurality of modulated signals that each have at least one sideband. The modulated signals are directed along a corresponding plurality of optical channels with outputs arranged in a second pattern corresponding to the first pattern. A composite optical signal is formed using light emanating from the outputs of the plurality of optical channels. Non-spatial information contained in at least one of the received RF signals is extracted from the composite signal.

Abstract: An optically-fed tightly-coupled array (TCA) antenna comprises a plurality of photodiodes and antennas. Each photodiode may receive an optical signal from an optical fiber and convert the optical signal into an RF driving signal to drive a corresponding antenna to which it is connected. Each photodiode may be connected to the antenna. In some examples, the TCA is capable of ultra-wideband operation ranging from 2-12 GHz and wide beam-steering capability up to 40° from the broadside. Inductance peaking and resistance matching may be employed.

Abstract: An transmitter to be used in wireless multi-user MIMO has been described above. The system combines the virtues of digital, analog and optical processing to arrive at a solution for scalable, non-blocking, simultaneous transmission to multiple UE-s. The system architecture is independent of the RF carrier frequency, and different frequency bands can be accessed easily and rapidly by tuning the optical source (TOPS). The data channels are established in the digital domain and the RF beam-forming accuracy is only limited by the available resolution of DAC, which can be as high as 16 bits for 2.8 GSPS in off-the-shelf components.

Abstract: A system and method reconstructs RF sources in k-space by utilizing interference between RF signals detected by an array of antennas. The system and method may include detecting an RF interference pattern resulting from interference between RF signals in an RF coupler, where the RF signals are detected by the antennas and provided to the RF coupler by RF waveguides. The RF waveguides may have unequal RF path lengths. K-space information of the RF sources may be reconstructed from the detected RF interference pattern using known tomography reconstruction methods.

Abstract: An optical imaging system and method that reconstructs RF sources in k-space by utilizing interference amongst modulated optical beams. The system and method involves recording with photodetectors the interference pattern produced by RF-modulated optical beams conveyed by optical fibers having unequal lengths. The photodetectors record the interference, and computational analysis using known tomography reconstruction methods is performed to reconstruct the RF sources in k-space.

Abstract: A method of RF signal processing comprises receiving an incoming RF signal at each of a plurality of antenna elements that are arranged in a first pattern. The received RF signals from each of the plurality of antenna elements are modulated onto an optical carrier to generate a plurality of modulated signals that each have at least one sideband. The modulated signals are directed along a corresponding plurality of optical channels with outputs arranged in a second pattern corresponding to the first pattern. A composite optical signal is formed using light emanating from the outputs of the plurality of optical channels. Non-spatial information contained in at least one of the received RF signals is extracted from the composite signal.

Abstract: A phased antenna array comprises a plurality of antennas and photodiodes arranged on a substrate. Each antenna is driven by an electrical signal output by the photodiode. The photodiodes each receive an optical signal via an optical fiber. The optical fibers conform to the sheet-like shape of the antenna array (which may be planar or curved) and optically communicate with a corresponding photodiode via a corresponding reflector, such as a ninety degree reflector. The reflectors may comprise a v-groove in a silicon substrate on which the optical fiber is positioned and a reflecting surface. Each reflector may be attached to the substrate or a ground plane positioned parallel to the substrate and the optical fiber may connect to the reflector in a direction running parallel to the phased antenna array. This optical feed network may accommodate tight spacing of the antenna elements (such as spacing less than 5 mm apart) with a thin profile.

Abstract: An optical imaging system and method that reconstructs RF sources in k-space by utilizing interference amongst modulated optical beams. The system and method involves recording with photodetectors the interference pattern produced by RF-modulated optical beams conveyed by optical fibers having unequal lengths. The photodetectors record the interference, and computational analysis using known tomography reconstruction methods is performed to reconstruct the RF sources in k-space.

Abstract: A method of RF signal processing comprises receiving an incoming RF signal at each of a plurality of antenna elements that are arranged in a first pattern. The received RF signals from each of the plurality of antenna elements are modulated onto an optical carrier to generate a plurality of modulated signals that each have at least one sideband. The modulated signals are directed along a corresponding plurality of optical channels with outputs arranged in a second pattern corresponding to the first pattern. A composite optical signal is formed using light emanating from the outputs of the plurality of optical channels. Non-spatial information contained in at least one of the received RF signals is extracted from the composite signal.

Abstract: An optical feed network for a phased-array antenna may comprise a phase-based feed network that may include electro-optical phase shifting.