Hrl Laboratories, LLC

Hughes Aircraft Company

The Boeing Company

Hughes Electronics Corporation

Raytheon Company

The Directv Group, Inc.

Robert R Hayes

Willie W Ng

Daniel Yap

Peter Petre

Stanislav I Ionov

Irwin L Newberg

Andrew L Strodtbeck

Brian N Limketkai

David A Langsam

Cecilia Y Cheng

James H Schaffner

Keyvan R Sayyah

Robert A Rosen

Kapriel V Krikorian

Robert Y Loo

George C Valley

William B Bridges

Hossein H Izadpanah

Shubha Kadambe

Adrian E Popa

Harry T Wang

John K Keigharn

Thomas R Cooper

Irina Ionova, Legal Representative

Alan R Kost

Bill H Otoide

Willie N Ng

Andrew Walston

The present invention describes a microresonator that can be used as a 1:f variable coupler in a unit cell. It is described how a cascade of unit cells can be used to form a tunable, higher-order RF-filter with reconfigurable passbands. The disclosed filter structure can be utilized for the narrowband channelization of RF signals that have been modulated onto optical carriers. It is also disclosed how to utilize add/drop capabilities of the contemplated microdisks to confer connectivity and cascading in two dimensions. The present invention can conveniently provide a wavelength division multiplexing router, where an array of unit cells as provided herein can form a programmable optical switching matrix, through electronic programming of filter parameters.

Reconfigurable optical filters formed by integration of electrically tunable microresonators

In one of many possible implementations and embodiments, a method is provided for providing linearized phase modulation and demodulation in an RF-photonic link. This includes phase modulating a photonic carrier signal in a signal arm using the RF input and using the RF output in a negative feedback phase tracking loop to modulate either the RF input modulated carrier signal in the signal arm, or a signal in a local oscillator arm. Optical signals from the signal arm and the local oscillator arm are optically coupled. The optically coupled signals are photodetected and differentally combined. The differentially combined signals are amplified to provide the RF output signal. In some implementations, the photonic carrier signal is suppressed prior to photodetection. Further, in some implementations a small portion of the local oscillator signal may be coupled with the carrier suppressed optical signal.

Coherent RF-photonic link linearized via a negative feedback phase-tracking loop

In one embodiment, a down conversion receiver is provided for a phase modulated optical signal. This may include an optical coupler coupled to be capable of receiving a phase modulated signal and a local oscillator signal, and a modulator coupled to an input of the optical coupler so as to be capable of modulating one of: (1) a phase modulated signal; or (2) a local oscillator signal. A photodetector circuit is located to be capable of detecting signals coupled by the optical coupler, with a sub-band selector circuit coupled to be capable of receiving signals from the photodetector circuit. The sub-band selector circuit has an output coupled to a modulating input of the modulator.

Down conversion for distortion free recovery of a phase modulated optical signal

There is provided in one of the embodiments of the disclosure a lithium niobate modulator structure for mitigating DC bias drift comprising a highly doped semiconductor layer patterned above an optical waveguide having one or more DC sections and an RF section, wherein a metal layer or contact is in contact with a portion of the semiconductor layer and a buffer layer is deposited in the RF section. There is provided in another embodiment of the disclosure a method for making a lithium niobate electro-optical modulator for mitigation of DC bias drift.

Lithium niobate modulator having a doped semiconductor structure for the mitigation of DC bias drift

The present invention relates to a laser transmitter capable of being configured to transmit one of a plurality of wavelengths. Specifically, the laser transmitter may be reconfigured using the resonance passbands of a tunable microresonator coupled with a fixed grating.

Wavelength reconfigurable laser transmitter tuned via the resonance passbands of a tunable microresonator

Transversal equalization is used to obtain broadband linearization of photonic modulation. A photonic link comprises a signal path and a feed-forward path. The feed-forward path includes an optical linearizer and a transversal equalizer connected with the optical linearizer. In this way, amplitude and phase matching of the error in the signal path is obtained over a wide bandwidth. This, in turn, enables a broadband enhancement of the link's spur free dynamic range (SFDR).

Broadband linearization of photonic modulation using transversal equalization

Electromagnetic radiation sources operating in the Terahertz (THz) region capable of overcoming the Manley-Rowe limits of known optical schemes by achieving phase matching between a THz wave and optical pulse in a nonlinear waveguide, or by achieving both phase and group velocity matching between a THz wave and optical pulse in a nonlinear waveguide to yield even higher efficiencies in converting optical power to the THz region.

Highly efficient waveguide pulsed THz electromagnetic radiation source and group-matched waveguide THz electromagnetic radiation source

An architecture that enables one to realize a FIR transversal filter with apodized, interlaced bipolar tap coefficients (a). The tap coefficients, a, are varied via the control of the optical powers emitted by an array of WDM laser sources. Also, a filter architecture where tap coefficients can be agilely reconfigured in both polarity and magnitude. One chirped fiber-grating may be used to implement a series of wavelength-dependent tap-weights. The filter designs can be utilized to eliminate the low-pass response centered at DC, allowing one to place the center frequency (f)of the first passband at a targeted intermediate frequency (IF).

Bipolar RF-photonic transversal filter with dynamically reconfigurable passbands

A method and apparatus that can generate two frequencies separated by the atomic hyperfine frequency separation needed to excite resonance in a Cs atom. In the present invention a coherent light source is frequency modulated with a modulation frequency having a sine wave to generate a lightwave. The lightwave comprises the two coherent optical fields having the frequency separation needed to excite resonance in the Cs atom. The modulation frequency can then be adjusted in order to fine-tune the frequency separation of the two coherent optical fields. The present invention also provides a method for localizing about 50% of the power in the lightwave at the two coherent optical fields by frequency modulating the light source with a square wave.

Method and apparatus for generating two frequencies having a frequency separation equal to the atomic frequency of an atomic species

A data signal is modulated onto an optical carrier, sub-band channels are then removed therefrom by microresonators, and each data sub-band channel is then combined in a detector with a corresponding local oscillator optical signal removed by a microresonator from a frequency comb modulated onto another optical carrier.

Method and apparatus for optical division of a broadband signal into a plurality of sub-band channels

A method and apparatus for generating a series of positive and negative signals from an optical signal. The optical signal is fed into a loop of optical fiber. The loop of optical fiber is provided with a first and second directional coupler. As the optical signal circulates through the optical loop, the first and second directional coupler extract a percentage of light from the optical signal, and couple the extracted light to a photodetector which converts the extracted light into electrical energy. The present invention also provides an impulse cancellation line. The impulse cancellation line is provided to neutralize the problematic initial light extracted from the optical signal in the first directional coupler and coupled to the photodetector. However, as the optical signal continues to circulate through the optical loop, the extracted light is not neutralized.

Recursive optical delay line filter with neutralization

An optical communication terminal transmits data via an optical signal with a transmit mirror positioned to direct the optical signal. The optical communication terminal includes a processor configured to develop a control signal for a mirror controller to establish an optimal position of the transmit mirror. The optical communication terminal further includes a modulator coupled to the processor that modulates the optical signal in accordance with a position of the transmit mirror during transmission of the optical signal. The optimal position of the transmit mirror may be established by a scanning routine that adjusts the position of the transmit mirror to a plurality of predetermined offset positions during transmission of the optical signal. The intensity of the optical signal as received by a further optical communication terminal is then determined and provided via modulation of a further optical signal transmitted back to the first-named optical communication terminal. The predetermined offset positions and the corresponding received intensities may then be utilized to determine the optimal position of the transmit mirror.

Alignment system and method for optical satellite communication

A method and apparatus for pulse frequency modulation for analog optical communication. A train of optical pulses is generated. The spectrum of the optical pulses in the train of optical pulses can be broadened to provide a train of broad spectrum optical pulses. The broadening can be provided by self-phase modulation. Alternatively, broad spectrum optical pulses can be provided by merely having the optical pulses be less than 1 ps duration. A desired optical frequency slice from the train of spectrum broadened optical pulses is selected by a tunable Fabry-Perot filter. A desired optical frequency slice from the broad spectrum optical pulses is selected by a tunable Fabry-Perot filter. The tunable Fabry-Perot filter has a pair of Distributed Bragg Reflectors separated by an electro-refractive section. The electro-refractive section has tuning electrodes for applying transverse electric fields to the electro-refractive section, corresponding to an analog waveform being applied to the tuning electrodes, to provide a pulse-frequency modulated train of optical pulses.

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Calabasas, CA, United States of America

Robert R Hayes