Photonic Systems, Inc.

Edward I Ackerman

Charles H Cox

William K Burns

Gary E Betts

Harold V Roussell

Joelle Prince

A method of separating a desired signal from an undesired signal includes obtaining a total input signal comprising the desired signal and the undesired signal in a time domain occupying a time duration from time tto time tof a single symbol in the desired signal. A transform is performed of the total input signal wherein an output of the transform is a time domain signal representing the desired signal.

RF signal separation and suppression system and method

A same-aperture any-frequency simultaneously transmit and receive (STAR) system includes a signal connector having a first port electrically coupled to an antenna, a second port electrically coupled to a transmit signal path, and a third port electrically coupled to receive signal path. The signal connector passes a transmit signal in the transmit signal path to the antenna and a receive signal in the receive signal path. A signal isolator is positioned in the transmit signal path to remove a residual portion of the receive signal from transmit signal path. An output of the signal isolator provides a portion of the transmit signal with the residual portion of the receive signal removed. A signal differencing device having a first input electrically coupled to the output of the signal isolator and a second input electrically coupled to the third port of the signal connector subtracts a portion of the transmit signal in the receive signal path thereby providing a more accurate receive signal.

Same-aperture any-frequency simultaneous transmit and receive communication system

A method of interference suppression with intermodulation distortion mitigation includes processing an RF signal comprising an RF signal of interest and an RF interfering signal to produce a first and second RF drive signal each with a desired RF interference signal power and having a 90 degree relative phase. The first RF drive signal is imposed onto a first optical signal with a modulator to generate a first modulated optical signal so that the modulator has a large-signal behavior that is characterized by a Bessel function of the first kind J(&#x3d5;), wherein the desired power at a frequency of the interference signal of the first drive signal is chosen to correspond to a zero of the Bessel function of the first kind J(&#x3d5;). The second RF drive signal is imposed onto a second optical signal with a modulator to generate a second modulated optical signal so that the modulator has a large-signal behavior that is characterized by a Bessel function of the first kind J(&#x3d5;), wherein the desired power at a frequency of the interference signal of the second drive signal is chosen to correspond to another zero of the Bessel function of the first kind J1(&#x3d5;). The first and second modulated optical signal are combined with an optical power ratio that is selected to suppress third-order intermodulation distortion products in an electrical signal generated by detecting the optically combined first and second modulated optical signals.

Interference suppression with mitigation of intermodulation distortion

An electromagnetic interface having an impedance with a resistive and a reactive component generates an electromagnetic field in both the reactive near-field region and the radiating far-field. A sensing circuit generates voltage and/or current having at least one of real and imaginary components that are proportional to an electromagnetic field in at least one of the reactive near-field region and the radiating far-field region. An electromagnetic modifier minimizes the electromagnetic field in the reactive near-field region in response to the signal generated at the output of the electromagnetic sensor.

Method and apparatus for electromagnetic field manipulation using near-field and far-field sensing

A linearized electro-optic modulator includes a substrate comprising a first Mach Zehnder interferometer comprising a first and second optical waveguide and a second Mach Zehnder interferometer comprising a first and a second optical waveguide. A signal electrode is positioned on the substrate to receive a modulation signal. First and second ground electrodes are positioned on the substrate and are electrically connected to ground potential. The signal electrode and the first and second ground electrodes are positioned so that an electric field generated by the signal electrode modulates both the first and second Mach Zehnder interferometers to generate a first and a second linearized modulated optical signal.

Inherently broadband linearized electro-optic modulator with customizable performance

A radio frequency (RF) signal separation and suppression system includes an input that couples in a radio frequency signal comprising desired and undesired radio frequency signals. The RF signal separation and suppression system also includes a reproduction generator connected to the input. The reproduction generator produces a reproduction from the radio frequency signal of the undesired signal at an output. The RF signal separation and suppression system also includes an electrical subtractor having a first input that is electrically connected to the output of the reproduction generator and a second input that is electrically connected to the input of the radio frequency signal separation system. An output of the subtractor generates an output radio frequency signal comprising the desired radio frequency signal and a suppressed undesired radio frequency signal.

An electromagnetic field optimization apparatus providing a means of more independently modifying the field in either the reactive near-field region or the far-field region while having significantly less modification to the other field. This means that a design to affect the real component of the impedance that affects the radiation in the far-field region does not affect, or minimally affects, the reactive component of the impedance that affects the field in the reactive near-field region.

An electro-optic modulator includes a Mach-Zehnder interferometer having a bias input, an optical input, and an optical output. A first arm comprises an optical waveguide. A second arm comprises an optical waveguide. A plurality of electrode segments is distributed along or proximate to a length of the optical waveguides of the first and second arms. A plurality of amplifiers, where at least one of the plurality of amplifiers has an RF input that receives an electrical modulation signal, and where each of the plurality of amplifiers are electrically connected to one of the plurality of electrode segments so as to provide distributed gain. A number of the plurality of amplifiers is chosen to achieve a desired combination of noise figure and spur-free dynamic range.

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Cambridge, MA, United States of America

Edward I Ackerman