Hrl Laboratories, LLC

Hughes Aircraft Company

Hughes Electronics Corporation

Raytheon Company

The Aerospace Corporation

Willie W Ng

Daniel Yap

Robert R Hayes

Gregory L Tangonan

Mohiuddin Ahmed

Celestino J Gaeta

Stephen L Bourgholtzer

James H Schaffner

Robert Y Loo

Irwin L Newberg

Troy Dean Rockwood

Metin S Mangir

David L Persechini

Daniel Frederic Sievenpiper

Peter Petre

Robert A Rosen

Daniel J Gregoire

Tsung-Yuan Hsu

Jar Jar Lee

Kapriel V Krikorian

Joseph S Colburn

Shankar R Rao

Joseph L Pikulski

George C Valley

Kevin Geary

Shubha Kadambe

Brian N Limketkai

Richard C Lind

Harry T Wang

Michael Wechsberg

J J Lee

George Anthony Sefler

Andrew A Walston

Huan W Yen

Robert H Buckley

Andrew Walston

A controllable opto-electronic time stretcher comprising a first wave guide and a second waveguide coupled to the first waveguide along a coupling portion; wherein at least one of the first and second waveguides in the coupling portion has a controllable refractive index.

Controllable opto-electronic time stretcher, an electro-optical analog to digital converter having non-uniform sampling using the same, and related methods of operation

A back end-circuit for randomized non uniform and alias-free subsampling, comprising: an analog-to-digital converter (ADC) configured for sampling an input signal at random non uniform times; a compressive sensing processor, coupled to the ADC, to recover a sparse spectral representation of the input signal; and a Fourier transformer for converting the sparse spectral representation to a time sampled representation of the input signal.

Hardware based compressive sampling ADC architecture for non-uniform sampled signal recovery

This invention provides an approach to lock the optical phase of a single sideband, carrier-suppressed coherent-AM analog optical link, so that for example an RF signal can be transmitted with high fidelity over fibers. In some embodiments, a method comprises providing a RF locking signal; impressing an RF input signal and the RF locking signal onto the optical field of a suppressed carrier; introducing the optical spectrum to a photonic integrated circuit comprising a microresonator filter and a finite impulse response filter; selectively passing the double sideband, associated with the locking frequency, through the finite impulse response filter; and recovering a RF output signal, wherein a feedback loop provides dithering to stabilize the optical phase of the link and thus preserve amplitude/phase integrity for the RF-photonic signal. The disclosed method is especially suited to the filtering of RF-photonic signals via use of the resonance passbands derived from microdisks or micro-rings.

Methods and apparatus for locking the optical phase of single-sideband amplitude-modulation signals

A method of performing analog to digital conversation of an analog signal V(t), the method including the steps of: utilizing both of the complementary arms of an electro-optic modulator to recover the analog input signal V(t), while using only one time-stretch element and one &#x3bb;-demultiplexer after the electro-optic modulator. The single time-stretch element and one &#x3bb;-demultiplexer serve to stretch and demultiplex the signals from both of the complementary output arms of the electro-optic modulator thereby improving and simplifying post-processing algorithms used to correct for static distortions and nonlinearities that originate from imperfect photonic hardware. Double-balanced photoreceivers are preferably coupled to outputs of the single &#x3bb;-demultiplexer. The single time-stretch element is preferably implemented by a chirped fiber grating. Apparatus for carrying out the method is described.

Wideband high resolution time-stretched photonic analog-to-digital converter

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 some variations, the present invention provides a method for forming a chip-scale photonic frequency channelizer or spectrum analyzer. A low-loss waveguide forms a long delay-line in a first level, from which a large number of filter-taps form narrow channel passbands. Multi-dimensional laser-written waveguides feed a slab waveguide coupler located at a stacked, second level. A chip-scale RF-photonic spectrum analyzer provided by this invention has extremely high resolution, such as a passband width of about 30 MHz over a free spectral range of 12 GHz, while occupying a device footprint of only about 10 cmarea.

High-resolution multi-level frequency channelizers

A method and apparatus for implementing an RF photonic transversal filter that utilizes tap apodization and wavelength reuse to obtain a high side lobe suppression together with narrow and configurable passbands. Several taps are obtained from one wavelength by using dispersive optical delay lines such as chirped fiber gratings that introduce a delay between successive wavelengths. A selected subset of the input wavelengths is utilized to generate multiple taps per wavelength. Some of the taps are apodized to generate various filter transfer functions that yield a high side lobe suppression ratio.

RF-photonic transversal filter method and apparatus

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

A method of and apparatus for modulating an optical carrier by an incident electromagnetic field. The electromagnetic field propagates in a dielectric-filled transverse electromagnetic waveguide, At least one slice of an electro-optic material is disposed in the dielectric-filled transverse electromagnetic waveguide, the electro-optic material in the dielectric-filled transverse electromagnetic waveguide having at least one optical waveguide therein which has at least a major portion thereof guiding light in a direction orthogonal with respect to a direction in which the dielectric-filled transverse electromagnetic waveguide guides the incident electromagnetic field. Light is caused to propagate in the at least one optical waveguide in the at least one slice of an electro-optic material in the dielectric-filled transverse electromagnetic waveguide for modulation by the incident electromagnetic field.

Microwave receiver front-end assembly and array

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

A laser transmitter with a feedback control loop for minimizing noise. The novel laser transmitter includes a laser, an external reflector adapted to form an extended cavity to the laser, and a feedback control loop adapted to detect noise in the laser and in accordance therewith, adjust the optical phase of the extended cavity such that the noise is at a desired level. The optical phase of the extended cavity is adjusted by adjusting an operating parameter of the laser, such as its bias current. In an illustrative embodiment, the feedback control loop is adapted to compute the rate of change of the noise with respect to bias current and in accordance therewith, adjust the bias current of the laser such that relative intensity noise and interferometric intermodulation distortion are simultaneously minimized.

System and method for reducing interferometric distortion and relative intensity noise in directly modulated fiber optic links

Growing community of inventors

Agoura Hills, CA, United States of America

Willie W Ng