Patent application number | Description | Published |
20080310847 | OPTICAL FREQUENCY DIVISION MULTIPLEXED COMMUNICATIONS OVER THE HORIZON - A non-line of sight (NLOS) communications system and method are provided that implement orthogonal frequency, division multiplexing. A data generator produces a digital data stream, which is converted into M parallel frequency sub-carrier digital data streams (where M is an integer), each sub-carrier is encoded with data and an Inverse Fast Fourier Transform operation is applied, and an output signal is converted to an analog signal, which is imposed onto an optical beam generated by a light source. The beam is transmitted skywards at an elevation angle above the horizon in at least one direction. The beam is scattered due to Mie and Raleigh effects, forming a scattered waveform. At least a part of the scattered waveform is received by a receiver outputting an electrical signal, which enters a DSP unit. The DSP unit digitizes the electrical signal, performs Fourier transformation and recovers data from M sub-carrier signals. | 12-18-2008 |
20090067772 | MICROWAVE PHOTONIC DELAY LINE WITH SEPARATE TUNING OF OPTICAL CARRIER - This invention provides a tunable delay of an optical signal having a carrier with an angular frequency ω | 03-12-2009 |
20090123107 | TUNABLE OPTICAL GROUP DELAY BASED ON MICRORESONATOR STRUCTURES - This invention provides a tunable delay of an optical signal having multiple frequency components. The delay comprises at least a first and a second integrated resonators coupled sequentially to a waveguide; the resonators have angular resonant frequencies ω | 05-14-2009 |
20090142051 | COHERENT OPTICAL DETECTOR AND COHERENT COMMUNICATION SYSTEM AND METHOD - An optical device is provided with first and second inputs. A first coupler coupled is coupled to the first input and produces at least a first and second output. A second coupler is coupled to the second input and produces at least a first and second output. A third coupler is coupled to the first output of the first coupler and to the first output of the second coupler. A fourth coupler is coupled to the second output of the first coupler and to the second output of the second coupler. First and second crossing waveguides are provided with an angle selected to minimize crosstalk and losses between the first and second cross waveguides. The first crossing waveguide connects one of the first or second outputs from the first coupler with an input of the fourth coupler. The second crossing waveguide connects one of the first or second outputs from the second coupler with an input of the third coupler. A first phase shifter is coupled to the first and second waveguides. The first and second waveguides connect one of the outputs of the first or second coupler and one of the inputs of the third or fourth couplers. The first, second, third and fourth couplers, the two crossing waveguides and the phase shifter are each formed as part of a single planar chip made of an electro-optical material. | 06-04-2009 |
20090169221 | OPTICAL RECEIVER USING BEAM COMBINING AND SYSTEM USING THE SAME - An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free space optical communications, remote sensing, optical imaging and others. A multitude of transverse scattered optical beam portions is captured by the multi-aperture array positioned perpendicular to the beam projection direction. These beam portions are combined first into a single optical waveguide with minimal loss of power. This is achieved by modulating the beam portions phase and coupling ratio of couplers in the optical beam combiner tuned to maximize the final output power. The data is recovered from the received optical beam using coherent detection. | 07-02-2009 |
20090185811 | SPACE DIVERSITY OPTICAL RECEIVER AND SYSTEM AND METHOD USING THE SAME - An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free space optical communications, remote sensing, optical imaging and others. A multitude of optical beam portions is captured by a space diversity receiver that includes an optical beam combiner, which has a tree-like topology with interconnected waveguides, electro-optic phase shifters, and directional couplers. For each of the beam portions the phase of the phase shifter and the coupling ratio of coupler in the optical beam combiner are tuned sequentially to maximize the final output power in the final optical waveguide. A portion of the final output beam is used for the power detection and forming a feedback signal for the phases and coupling ratios adjustment. The data or information is recovered from the received final optical beam using coherent detection. | 07-23-2009 |
20090190929 | OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLEXED COMMUNICATIONS WITH NONLINEARITY COMPENSATION - The present invention discloses a transmitter and receiver for optical communications system, which provide compensation of the optical link nonlinearity. M-PSK modulating is used for data embedding in an optical signal in each WDM channel using orthogonal frequency division multiplexing (OFDM) technique. At the receiver side electrical output signals from a coherent optical receiver are processed digitally with the link nonlinearity compensation. It is followed by the signal conversion into frequency domain and information recovery from each subcarrier of the OFDM signal. At the transmitter side an OFDM encoder provides a correction of I and Q components of a M-PSK modulator driving signal to compensate the link nonlinearity prior to sending the optical signal to the receiver. | 07-30-2009 |
20090220246 | OPTICAL RECEIVER AND A FREE-SPACE OPTICAL COMMUNICATIONS USING THE SAME - A device for phase distortion compensation across an optical beam is provided. The device is a part of an optical receiver, which can be used in free space optical communications, remote sensing, optical imaging and others. 2 | 09-03-2009 |
20090236528 | CHEMICAL SENSING SYSTEM AND METHOD - A photo-thermal, interferometric spectroscopy system is disclosed that provides information about a chemical, such as explosives and the like, at a remote location. It may be used for solid residue detection on a surface. The system includes a novel light detector system with a matrix of optical elements focusing portions of a received light beam on input waveguides of an optical combiner. The combiner adjusts the phases of the received beam portions and combines them together to maximize the intensity of an output beam. The output beam is detected by a detector, and information about at least one of, absorption spectrum and concentration of the chemical is recovered. In the preferred embodiment the detector is a coherent detector based on 90-degrees optical hybrid. | 09-24-2009 |
20090269083 | SPACE DIVERSITY RECEIVER FOR OPTICAL COMMUNICATIONS - An optical beam combiner is provided, which allows efficient collection of light for various applications: non-line of sight and free-space optical communications, remote sensing, optical imaging and others. A multitude of transverse scattered optical beam portions is captured by the multi-aperture array positioned perpendicular to the beam projection direction. These beam portions are combined first into a single optical waveguide with modulating the beam portions phase and coupling ratio of directional couplers in the optical beam combiner tuned to maximize the final output power. A portion of the output beam is used for the power detection and forming a feedback signal for the phases and coupling ratios adjustment. The data is recovered from the received optical beam using coherent detection. | 10-29-2009 |
20100135656 | OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLEXED COMMUNICATIONS WITH NONLINEARITY COMPENSATION - The present invention discloses a transmitter and receiver for optical communications system, which provide compensation of the optical link nonlinearity. M-PSK modulating is used for data embedding in an optical signal in each WDM channel using orthogonal frequency division multiplexing (OFDM) technique. At the receiver side electrical output signals from a coherent optical receiver are processed digitally with the link nonlinearity compensation. It is followed by the signal conversion into frequency domain and information recovery from each subcarrier of the OFDM signal. At the transmitter side an OFDM encoder provides a correction of I and Q components of a M-PSK modulator driving signal to compensate the link nonlinearity prior to sending the optical signal to the receiver. | 06-03-2010 |
20110019955 | TUNABLE OPTICAL GROUP DELAY - This invention provides a balanced thermal approach to the tuning of an optical time delay device in order to eliminate any long-term time response of the device performance due to thermal time constants of the device, its mount, packaging or electronic temperature control circuits. The invention provides multiple ways to improve the thermal tuning speed of the balanced thermal approach. Additionally, the invention overcomes an issue of microresonator non-uniformity by operating a large group of microresonators as a ‘super-ring’ by tuning the large group together to provide a controllable group delay with large bandwidth. | 01-27-2011 |
20110164299 | SUPER-RING RESONATOR BASED DEVICES - This invention provides an optical device comprising a large group of non-uniform resonators operating cumulatively as a ‘super-ring’ to provide a controllable group delay with large bandwidth. The super-ring tuning is performed by a single control. The device may include two super-rings, each includes a large number of resonators with a resonant frequencies centered around ω | 07-07-2011 |
20130108279 | LASER COMMUNICATION SYSTEM | 05-02-2013 |