An optical processor for controlling a phased antenna array uses a frequency-shifted feedback cavity (FSFC), which includes a traveling-wave cavity. The FSFC incrementally delays and incrementally frequency shifts optical signals circulating in the traveling-wave cavity. Optical signals coupled out of the FSFC are separated by frequency, hence by delay, and processed to control either or both transmit and receive beam-forming operations. The FSFC provides a receiver with multiple receive signals which have incremental values of frequency. Each frequency corresponds to an incremental time sampling of optical signals input into the FSFC. Transmit signals coupled out of the FSFC have frequency and phase relationships that result in short time-domain pulses when combined. Controlling modulation and frequency of the transmit signals achieves carrier interference multiple access, a new type of spread-spectrum communications.

Frequency-shifted feedback cavity used as a phased array antenna controller and carrier interference multiple access spread-spectrum transmitter

An adaptation to Carrier Interferometry synthesis and analysis provides for frequency-varying subcarriers. Coding and decoding functionality can be extended to orthogonal chirped and frequency-hopped waveforms. Poly-amplitude codes permit successive interference cancellation in spatial and frequency-domain processing. Dynamic re-sectorization and bandwidth exchange are facilitated by subcarrier allocation.

Carrier interferometry coding with applications to cellular and local area networks

A photonic device for controlling phased array beam direction includes an electro-optic substrate; a plurality of waveguides formed in the substrate, each of which is capable of simultaneously propagating light signals with orthogonal polarizations; an input waveguide for inputting into each one of the plurality of waveguides a pair of copropagating polarized light signals having orthogonal polarizations and different frequencies; a plurality of electrodes on the substrate configured to phase shift the signals traveling through each waveguide by a different amount in response to a common applied voltage, thereby creating phase shifted polarized signals; and means for combining the phase shifted polarized signals within each one of the waveguides and propagating these combined signal to an antenna element The basic operating principle of the invention is based on the differential phase shift between optical waves of orthogonal polarizations traveling in an electro-optic optical waveguide This differential phase shift is directly proportional to the voltage applied to a control electrode and to the length of that electrode If the two optical waves are slightly offset in optical frequency, they produce a beat frequency when photodetected whose phase shift equals the optical differential phase shift An array of such phase shifters forms the basis for the photonic beam controller of the invention

Phased array beam controller using integrated electro-optic circuits

In a method and apparatus for maintaining a minimum transmission power level between two communication stations, each station measures the other's received signal quality, and returns an indication of signal quality as part of a regular maintenance burst. Each station adjusts its own transmission power level based on the returned signal quality indication. The signal quality indication is based on the received ratio of bit energy to total noise power spectral density which is calculated from an estimated bit-error-rate.

Method and apparatus for bi-directional power control in a digital communication system

A system for scanning an antenna array of the present invention. The system includes a first mechanism for modulating a desired signal on an optical carrier signal. The first mechanism includes a frequency-tunable optical oscillator with a phase shifter for changing an output frequency of the optical oscillator. A second mechanism employs the optical carrier signal to derive signals having predetermined phase relationships. A third mechanism receives the feed signals and radiates corresponding transmit signals in response thereto to the antenna array to steer the array. In more specific embodiment, the desired signal is a Radio Frequency (RF) signal, and the phase shifter is an electrically controlled optical RF phase shifter. The optical carrier signal includes a first optical carrier signal and a second optical carrier signal. The frequency-tunable optical oscillator includes a first tunable optical oscillator for providing the first optical carrier signal and a second tunable optical oscillator for providing the second optical carrier signal. The first and second optical oscillators include first and second optical RF phase shifters, respectively, that include feedback paths having optical and electrical sections.

Optically frequency generated scanned active array

A method of controlling an active antenna comprising a matrix of individual transmitting/receiving elements. Two optical frequencies are superposed to generate an optical beat signal in the microwave frequency range. After electrical/optical conversion the beat signal is fed with a defined phase and amplitude to the individual transmitting/receiving elements of the antenna.

Method and apparatus for controlling an active antenna

A method for controlling an active antenna of individual transmitting/receiving elements, an optical beat signal being generated in the microwave frequency range by heterodyning two optical frequencies and, after electro-optical conversion, being applied with defined phase and amplitude to the individual transmitting/receiving elements of the antenna.

Method for controlling an active antenna

Vorrichtung zur ansteuerung einer aktiven antenne

In this method, in each case one of the high-frequency signals (Si) to be measured modulates one branch of a centrally generated optical carrier signal (B) and the modulated optical signals of the individual branches are subsequently superimposed to form an aggregate signal (C), - the optical path lengths being selected to be different for each branch and - the aggregate signal (C) being measured with regard to amplitude and phase of the principal line and at least one side band relative to the centrally generated carrier signal (B) for a number of frequencies of the centrally generated optical carrier signal, and - the response of the individual branches being determined separated from one another from the frequency response thus determined for the principal line and at least one side band at a number of frequencies of the centrally generated optical carrier signal (B), the response of the side band of one branch being normalised to the response of the associated principal line.

Michael Dipl Phys Voelker

Papers

Method and apparatus for controlling an active antenna

Method for controlling an active antenna

Vorrichtung zur ansteuerung einer aktiven antenne

Method for measuring the amplitude and phase of a plurality of high frequency signals.

Verfahren zur Messung von Amplitude und Phase mehrerer hochfrequenter Signale