An optical-electronic integrated RF leakage interference cancellation system and method for continuous wave radars belongs to the technical filed of radars. The optical-electronic integrated RF leakage interference cancellation system cancels the RF leakage interference by integrating of the microwave photonic link and the cable link. The microwave photonic link implements the phase adjustment, time delay adjustment and amplitude adjustment of the microwave signal tapped from the continuous wave source in the transmitter and realizes the cancellation matching conditions of the out of phase, the matching delay time and the same amplitude with the leakage interference signal. It has the advantages of broad frequency band, large bandwidth, and high tuning resolution, which enables the effective suppression of the RF leakage interference and ensures the high transmit-to-receive isolation for continuous wave radars.

Devices, methods and systems for generating wideband, high-fidelity arbitrary radio frequency (RF) passband signals are described. A voltage tunable optical filter for arbitrary RF passband signal generation includes a first input configured to receive a broadband optical pulse train, a second input configured to receive a first control voltage representative of an amplitude signal, an electrooptic modulator to receive the broadband optical pulse train and the first control voltage, to modulate the broadband optical pulse train in accordance with the amplitude signal, and to produce two complementary optical outputs that form two arms of an interferometer, an optical delay component to impart an optical path difference into one of the complementary outputs of the electrooptic modulator, and a combiner or a splitter to receive two complementary optical outputs of the electrooptic modulator after impartation of the optical path difference and to produce an output interference pattern of fringes.

Methods, devices and systems for providing accurate measurements of timing errors using optical techniques are described. An example timing measurement device includes an optical hybrid that receives two optical pulse trains and produces two or more phase shifted optical outputs. The timing measurement device further includes two or more optical filters that receive the outputs of the optical hybrid to produce multiple pulse signals with distinctive frequency bands. The device also includes one or more photodetectors and analog-to-digital converters to receive to produce electrical signals in the digital domain corresponding to the optical outputs of the hybrid. A timing error associated with the optical pulse trains can be determined using the electrical signals in digital domain based on a computed phase difference between a first frequency band signal and a second frequency band signal and a computed frequency difference between the first frequency band signal and the second frequency band.

The disclosed systems, apparatuses and methods are directed to controlling a difference between a first center frequency of a first optical subcarrier and a second center frequency of a second optical subcarrier of an optical super-channel signal in an optical network. The method comprises modulating the first optical subcarrier at a first optical side component frequency with a first side modulation frequency and modulating the second optical subcarrier at a second optical side component frequency with a second side modulation frequency. The method further comprises detecting a radio-frequency (RF) power at a modulated beat frequency tone in the modified optical signal.

Device, methods and systems for the electronic demodulation of optically phase demodulated signals are described. An example optical local oscillator generator configured to generate a radio frequency (RF) tone at a desired RF frequency includes a first input configured to receive a broadband optical pulse train, a second input coupled to a delay line interferometer to receive a first control voltage for controlling a delay value of the interferometer and to produce an output optical pulse train, a dispersive element, coupled to the delay line interferometer, to map the output optical pulse train to a time-domain modulated optical pulse train, an optical-to-electrical converter, coupled to the dispersive element, to convert the time-domain modulated optical pulse train to an analog electrical signal, and an RF filter, coupled to the optical-to-electrical converter, to filter the analog electrical signal to generate the RF tone at the desired RF frequency.

An RF signal to be carried by an optical link is modulated onto two optical beams. The modulators are tuned differently so that the distortion products carried on one beam are relatively larger compared to the fundamental compared with other beam. One of the beams is optically upconverted by the appropriate Brillouin shift frequency and the two beams counter-propagated through an optical waveguide in order to create a Brillouin grating. The grating acts to separate the distortion products from the fundamental so as to provide at an output of the link a signal in which the distortion products are insignificant is not absent.

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.

An optical delay method, and related system, includes propagating an optical signal along an optical delay device (10) with a first stage (11) having a variable input coupler (20) and a delay element. An intermediate stage (12) has a variable intermediate coupler (30) and a delay element. An output stage (13) includes a variable output coupler (40). The method sets a coupling ratio of the input (20) and output couplers (40) equal to a value K1 selected among a plurality of at least three values. A coupling ratio of the intermediate coupler (30) is set equal to a value K2, wherein K1=sin.sup.2() & K2=sin.sup.2(A*) with greater than or equal to zero and less than or equal to /2 and A greater than or equal to 1.5 and less than or equal to 2.5.

The subject matter described herein relates to various antenna element configurations, antenna array configurations, their operations including various systems and methods to generate modulated data for transmission by an RF antenna array via an optical processing engine. The subject matter includes optical processing engine structure and methods (e.g., modulating in the optical domain, MIMO and spatial modulation via RF beam formation, coherent transmission of RF signal components, coherent operation of spatially separate RF antenna arrays) that may be implemented with the various RF antenna array structures. In some examples, 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. Much of 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). In some examples, multiple communication channels may be transmitted simultaneously to different locations. The transmitter may be formed by an array of optically fed antennas.

An underwater wireless communication network includes a first buoyant platform, including a radio-frequency communication transceiver and a wired communication transceiver, floating at a surface of a body of water. A first underwater sensor node is coupled to the first buoyant platform by at least one wire over which the first buoyant platform and the first underwater sensor node communicate. The first underwater sensor includes a wired communication transceiver to communicate with the first buoyant platform over the at least one wire. The first buoyant platform or the first underwater sensor node includes a first ambient energy collector configured to power the first buoyant platform or the first underwater sensor node. A second underwater sensor node, arranged under the body of water, includes a second ambient energy collector configured to power the second underwater sensor node. The first and second underwater sensor nodes each comprise a sensor, an optical communication transceiver, and an acoustic positioning system.