Northrop Grumman Systems Corporation

Northrop Corporation

Trw Limited

Richard L Davis

Harold M Stoll

James G Ho

John C Brock

James J Reis

Thomas Jung

Terrance T Lam

Akhil R Shah

Sae H Lee

An integrated imaging spectrometer for hyperspectral imaging (HSI) system is disclosed. The integrated imaging spectrometer features photonic PLCs that include an array of input channel waveguides, one for each pixel of an image scene. Spectral grating filters are positioned along the length of each waveguide to extract the spectral components as the light propagates to the end of the waveguide. The filters route the optical energy to photodetectors and the detected electrical signals are captured by a read out integrated circuit (ROIC). Together the PLC, detectors, and ROIC form an imaging layer. Stacking imaging layers generates a device capable of recording an entire 3D high-resolution spatial/spectral image data cube in real-time.

Integrated imaging spectrometer for hyperspectral imaging systems

An optical channel waveguide having a reflection grating and a related method for its fabrication. The grating is apodized to provide a desired reflection or transmission spectral characteristic, by varying the grating width along the length of the grating in the direction of light propagation. The grating has multiple parallel elements extending across the waveguide channel width, and apodization is effected by appropriate selection of the width of each element relative to the width of the channel, without varying the grating duty cycle or other parameters.

Grating apodization technique for diffused optical waveguides

An optical channelizer system that is adapted to provide instantaneous RF signal channelization at frequencies on the order of 100 GHz or more into channels having bandwidth as small as a few megahertz. In order to improve the channel resolution the optical channelizer system is formed from a plurality of parallel subchannelizers, for example, twenty-five parallel sub channelizers which can provide 1 GHz channel spacing and 40 MHz signal resolution.

Hybrid coherent-optical, RF signal channelizer

A photonic arbitrary waveform modem utilizes a bipolar coding scheme. The bipolar coding scheme includes an arbitrary waveform modem which includes a plurality of tapped delay lines and is implemented by partitioning each optical frequency chip into positive and negative segments. Signals are decoded by effectively multiplying the transmit and receive code vectors and individually summing the positive and negative tap weights. The positive and negative tap weights are differenced to recreate the transmitted signal. The bipolar coding scheme allows for the use of truly orthogonal codes which decreases the interference and reduces the probability of detection.

Photonic bipolar modem for secure multi-channel communication

A compact and easily manufacturable waveguide optical frequency router ( ) is provided. The router ( ) has a transmit core region ( ) and a plurality of receive core regions ( ) formed within a slab region ( ). The router ( ) further includes an array of distributed Bragg deflectors (DBDs) ( ) formed within the core regions ( ) for coupling optical energy ( ) between the transmit core region ( ) and the receive core regions ( ) via the slab region ( ). The array of DBDs ( ) distributes the optical energy ( ) between the receive core regions ( ) based on optical wavelength and propagation angle.

Waveguide optical frequency router

A multispectral imaging system ( ) and method utilize an optical processor ( ) for simultaneously comparing an input wavelength spectrum observed in a single spatial pixel in a scene image from a multispectral imager ( ) with a plurality of template wavelength spectra to find a correlation. The optical processor exploits the three-dimensional attributes of optical correlation to perform massively parallel correlation processing by modulating ( ) respective ones of a plurality of spectral bands of the input wavelength spectrum of an incident light beam ( ) with modulating elements ( ) to alter at least one property of the incident light beam by a value corresponding to the observed intensity of the input spectrum in the respective spectral band. In a disclosed embodiment, the modulated beam is expanded and transited through a spatial light modulator ( ) having a two-dimensional array of modulating elements. Each row of the elements of the array alter the at least one property of the incident light by values corresponding to a particular template wavelength spectrum of a plurality of template wavelength spectra of the modulator. The values corresponding to each template spectrum are the conjugates of the representative values of the modulating elements of the template spectrum of the plurality of template spectra.

Multispectral imaging system and method

A mode locked semiconductor laser that can generate relatively high-power output pulses. The semiconductor mode locked laser is formed from an array of optical amplifiers that are coupled to a common resonant cavity by way of an optical channelizer or wavelength division multiplexer (WDM). By utilizing an array of optical amplifiers, the output pulses will have a relatively higher power than known mode locked lasers. As such, the mode locked semiconductor laser in accordance with the present invention does not depend on the power handling capability of the individual optical amplifiers and allows the average output power to be scaled, for example, up to the kilowatt range using semiconductor optical amplifiers. A mode locked laser in accordance with the present invention can be implemented with active mode locking, passive mode locking or a hybrid of the two. In embodiments utilizing active mode locking, the output pulse shape can be tailored by the amplifier drive current distribution.

Multi-amplifier, high power mode locked laser

In a method for addressing holograms stored in a plurality of separate storage media, a reference beam is directed to a selected one of the plurality of storage media, the reference beam is then focused so as to obtain a substantially flat wavefront within a reference beam plane of the selected storage medium, and the angle of the reference beam is then varied so as to select a hologram stored therein.

Reference beam auto-focus apparatus for modularized volume-holographic

A method is described for producing stacked optical waveguides in a silicon dioxide substrate and includes the steps of: etching a first trench in the substrate; filling the first trench with a glassy optical transmission media; depositing a layer of silicon dioxide over the filled trench; etching a second trench in the silicon dioxide layer, the second trench aligned with the first trench; and filling the second trench with a glassy optical transmission media.

Method for the production of optical waveguides employing trench and

A tunable, integrated WDM optic couler for coupling optical energy to and from channel waveguides in response to the application of Surface Acoustic Waves (SAW's ), and a distributed processor computer control system utilizing the couplers. A first range of SAW's is used to couple optical energy of selected wavelengths from a channel waveguide driven by a LED to multiplex optical energy to a common optic loop and a second, non-overlapping range of SAW's is used to couple optical energy from the loop to a second channel waveguide. The second, receiving channel waveguide includes a Bragg deflector, planar waveguide and photodetector arrays to demultiplex the optical energy by focusing selected wavelengths of optical energy on selected portions of the photodetector arrays. Changes in the acoustic wavelengths and amplitudes permit tuning of the coupler and computer system by altering the portion and wavelengths, respectively, of optical energy coupled by each section of each coupler.

High density integrated optical multiplexer/demultiplexer

An integrated optical waveguide structure which provides for efficient, single-mode propagation of light across an interface between two contiguous waveguide layers of differing effective refractive index. The waveguides are formed by layers of increased index of refraction formed at the surface of a substrate and serve to support propagation of optical electromagnetic radiation along the surface of the substrate. A refractive interface is provided at the interface of two such surface layers supporting modes of differing effective indexes of refraction. By underlying one of the surface layers with an additional layer having a particular, but different, index of refraction, a single mode of propagation is supported throughout both of the surface waveguides. General applications in the formation of optical waveguide components as well as a more extensive treatment with the formation of a lens is also disclosed using proton exchange in crystalline LiNbO.sub.3.

Refractive optical waveguide interface and lens

Described herein is an integrated acousto-optic circuit for analyzing the spectrum of a radar signal. A waveguided optical beam is first split into two parts, one of which interacts with a surface acoustic wave generated by a reference signal and the second of which interacts with a surface acoustic wave generated by the signal to be analyzed. The two resulting phase-modulated optical waves then are recombined, Fourier transformed by a lens and finally caused to impinge on an array of photodetectors. The array of detectors is arranged so that each element of the array responds to the combination of one component of the time-varying signal to be analyzed and one component of the time-varying reference signal, that response being an output signal at some preselected radio frequency which is proportional to the amplitude of the frequency component of the radar signal to be analyzed. The several optical components are disclosed as formed on a single substrate integrated optical circuit.

Growing community of inventors

Redondo Beach, CA, United States of America

Richard L Davis