Abstract: A system and method of adding a high-rate channel to a legacy baseband bus includes a bus communicatively coupled to a transmitter and a receiver via one or more transformer couplers, where the transmitter and receiver transmit and receive a first signal over the bus utilizing a differential mode. The system also includes at least two modems coupled to the bus, where a first modem transmits a second signal over the bus for receipt by a second modem, where the at least two modems are each coupled to the bus via the one or more transformer couplers, where the second signal is transmitted over the bus utilizing a common mode, and where the first signal and the second signal are spatially separated on the bus based on an isolation between the common mode and the differential mode.

Abstract: Provided are apparatus including a signal processing circuit. The signal processing circuit may be configured to process an input signal having an input bandwidth spanning a range of input radio frequencies, and may include a local oscillator to produce a local oscillator signal. In one embodiment, the signal processing circuit can include a staring mode of operation. In one embodiment, the signal processing circuit can include a selective mode of operation. In one embodiment, the signal processing circuit can include a staring mode of operation and a selective mode of operation.

Abstract: A high rate radio frequency (RF) link system and method for spatially multiplexing data transmission is presented. The system can comprise a common communications point characterized by a first collection of antennas having independent channels interconnected with a known latency connection to a central process location, such as with optical fiber; and a second similarly configured collective endpoint or set of endpoints wherein multi-path between the first collection and the second collection is negligible. Signal decorrelation between independent channels is achieved through a combination of spatial separation and signal processing. In one aspect, decorrelation is performed using near-maximum likelihood Multiple-Input Multiple-Output signal processing.

Abstract: A directional notch filter for simultaneous transmit and receive of wideband signals comprises an antenna, an antenna match, a receiver, a power combiner, a first directional coupler, a second directional coupler and a shaping filter accepting a signal and producing a compensation signal as a replica of an antenna reflection transfer function, wherein the first and second directional couplers produce signals and portions of signals received by the antenna and sent to the receiver via the power combiner. The receiver can produce a receiver signal and the first directional coupler can produce a first signal as a portion of an overall signal received by the antenna, the first signal comprising at least reflection of a signal from the power amplifier and the second directional coupler samples a small portion of the receiver signal, said second directional coupler producing a second signal.

Abstract: Apparatus and methods of simultaneous transmission and reception in a single-antenna radio transceiver. The transceiver may be used, for instance, for communication between at least two terminals, by use of multiple intermediate recruited transceiver nodes. The recruited transceiver nodes receive a signal from a master mode, and then retransmit the signal to a receiver. The recruited transceiver nodes are designed to have reduced interference between the transmit channel and the received channel. In accordance with one aspect of the present application, embodiments can achieve more robust wireless communication between a transmitter and an over-the-horizon receiver. The robust wireless communication will have improved resistance to interference, including self-interference, and improved communication range.

Abstract: A system and method for optimizing an optical RF photonic link system is presented. The system comprises a modulator subsystem in which nonlinear response is compensated by an envelope precompensation method and employs an optical filter to suppress optical carriers and extract modulated sidebands, an optical amplifier, and an array of photodetectors, each having a plurality of pairs of diodes. The modulator subsystem performs optical filtering on the signal, the signal is amplified by the optical amplifier and sent to the array of photodetectors. The optical amplifier can be an erbium doped fiber amplifier, or a phase sensitive amplifier. The optical power can be delivered to each diode of the array of photodetectors via a photonic integrated circuit.

Abstract: A system and method for transporting encrypted data having a transmitter and a receiver is provided. The transmitter generates a sequence of optical pulses, which are copied and output as identical channels. The identical channels are modulated by a plurality of modulators using data to generate a modulated data signal. Respective spectral phase encoders coupled to each of the plurality of data modulators encode respective modulated data signals using a plurality of mutually orthogonal phase codes that are individually associated with the respective spectral phase encoder. These encoded data signals are combined and code-scrambling by a spectral phase scrambler using a scramble code as an encryption key to generate an encrypted signal. A receiver reverses the encryption to extract the data.

Abstract: Systems and methods for improved photonically-assisted RF filtering. Presently, processing of wide-band RF signals involves the use of multiple specialized equipment to isolate a region of interest from the spectrum. The present invention discloses the use of a modulation system to upconvert the RF signal onto the sideband of a light source such as a laser, an optical filter sub-system comprising a plurality of filtering units that function as combinations of IIR and FIR filters, and a resonant channelizing filter for noise reduction and rejection of undesired channels, and means for control and agility of a piecewise coherent optical filter. The resulting filtered RF signal may then be downconverted to the electrical domain for further signal processing.

Abstract: A method for multiscale sampling for wide dynamic range electro-optic receivers is presented. The method comprises obtaining a signal, reproducing the signal into first and second signals, scaling one signal with respect to the other, modulating both signals with the same modulation function, and utilizing the resulting vector response function to invert the response of the link over a greater dynamic range than would otherwise be possible with a single instance of the modulated signal. The sealed modulation response may be obtained by splitting the signal into two polarizations and utilizing a modulator having different response for the two polarizations, or by utilizing two modulators.

Abstract: A system and method for optimizing an optical RF photonic link system is presented. The system comprises a modulator subsystem in which nonlinear response is compensated by an envelope precompensation method and employs an optical filter to suppress optical carriers and extract modulated sidebands, an optical amplifier, and an array of photodetectors, each having a plurality of pairs of diodes. The modulator subsystem performs optical filtering on the signal, the signal is amplified by the optical amplifier and sent to the array of photodetectors. The optical amplifier can be an erbium doped fiber amplifier, or a phase sensitive amplifier. The optical power can be delivered to each diode of the array of photodetectors via a photonic integrated circuit.

Abstract: A directional notch filter for simultaneous transmit and receive of wideband signals comprises an antenna, an antenna match, a receiver, a power combiner, a first directional coupler, a second directional coupler and a shaping filter accepting a signal and producing a compensation signal as a replica of an antenna reflection transfer function, wherein the first and second directional couplers produce signals and portions of signals received by the antenna and sent to the receiver via the power combiner. The receiver can produce a receiver signal and the first directional coupler can produce a first signal as a portion of an overall signal received by the antenna, the first signal comprising at least reflection of a signal from the power amplifier and the second directional coupler samples a small portion of the receiver signal, said second directional coupler producing a second signal.

Abstract: Apparatus and methods of simultaneous transmission and reception in a single-antenna radio transceiver. The transceiver may be used, for instance, for communication between at least two terminals, by use of multiple intermediate recruited transceiver nodes. The recruited transceiver nodes receive a signal from a master mode, and then retransmit the signal to a receiver. The recruited transceiver nodes are designed to have reduced interference between the transmit channel and the received channel. In accordance with one aspect of the present application, embodiments can achieve more robust wireless communication between a transmitter and an over-the-horizon receiver. The robust wireless communication will have improved resistance to interference, including self-interference, and improved communication range.

Abstract: A high rate radio frequency (RF) link system and method for spatially multiplexing data transmission is presented. The system can comprise a common communications point characterized by a first collection of antennas having independent channels interconnected with a known latency connection to a central process location, such as with optical fiber; and a second similarly configured collective endpoint or set of endpoints wherein multi-path between the first collection and the second collection is negligible. Signal decorrelation between independent channels is achieved through a combination of spatial separation and signal processing. In one aspect, decorrelation is performed using near-maximum likelihood Multiple-Input Multiple-Output signal processing.

Abstract: A system and method for transporting encrypted data having a transmitter and a receiver is provided. The transmitter generates a sequence of optical pulses, which are copied and output as identical channels. The identical channels are modulated by a plurality of modulators using data to generate a modulated data signal. Respective spectral phase encoders coupled to each of the plurality of data modulators encode respective modulated data signals using a plurality of mutually orthogonal phase codes that are individually associated with the respective spectral phase encoder. These encoded data signals are combined and code-scrambling by a spectral phase scrambler t using a scramble code as an encryption key to generate an encrypted signal. A receiver reverses the encryption to extract the data.

Abstract: A method for multiscale sampling for wide dynamic range electro-optic receivers is presented. The method comprises obtaining a signal, reproducing the signal into first and second signals, scaling one signal with respect to the other, modulating both signals with the same modulation function, and utilizing the resulting vector response function to invert the response of the link over a greater dynamic range than would otherwise be possible with a single instance of the modulated signal. The sealed modulation response may be obtained by splitting the signal into two polarizations and utilizing a modulator having different response for the two polarizations, or by utilizing two modulators.

Abstract: Systems and methods for improved photonically-assisted RF filtering. Presently, processing of wide-band RF signals involves the use of multiple specialized equipment to isolate a region of interest from the spectrum. The present invention discloses the use of a modulation system to upconvert the RF signal onto the sideband of a light source such as a laser, an optical filter sub-system comprising a plurality of filtering units that function as combinations of IIR and FIR filters, and a resonant channelizing filter for noise reduction and rejection of undesired channels, and means for control and agility of a piecewise coherent optical filter. The resulting filtered RF signal may then be downconverted to the electrical domain for further signal processing.

Abstract: A method and system to economically monitor an optical OOK signal that can detect perceptible changes in signal quality and identify the type of optical impairment causing the change. The invention requires a new and novel combination of known techniques to create an eye diagram of the transmitted pulse in a wavelength division multiplexing systems and then removing the noise from the eye diagram. Economy of operation is achieve by using asynchronous sampling techniques for generating the eye diagram. The resulting “cleaner” eye diagram is then analyzed to identify any changes in performance. In the preferred embodiment, the analysis is conducted on histograms generated from eye diagram, the histograms are computed at a number of points across the optical signal pulse period.

Abstract: Apparatus and system for transmitting and receiving optical code division multiple access data over an optical network. The apparatus comprises a spectral phase decoder for decoding the encoded optical signal to produce a decoded signal, a time gate for temporally extracting a user signal from the decoded signal, and a demodulator that is operable to extract user data from the user signal. The system preferably comprises a source for generating a sequence of optical pulses, each optical pulse comprising a plurality of spectral lines uniformly spaced in frequency so as to define a frequency bin, a data modulator associated with a subscriber and operable to modulate the sequence of pulses using subscriber data to produce a modulated data signals and a Hadamard encoder associated with the data modulator and operable to spectrally encode the modulated data signal to produce an encoded data signal.