Patent application number | Description | Published |
20090092392 | VIRTUAL I/Q MULTIPLEXING IN OPTICAL CODE DIVISION FOR SECURE LOCAL AREA OFDM - A system and method for virtual I/Q multiplexing in optical code division for secure local area OFDM includes encoding a wide spectrum signal, which includes a plurality of spectral bins, to provide a complementary spectral coding over at least two channels. The complementary spectral codings are intensity modulated with opposite polarity for each channel. An M-ary Orthogonal Frequency Division Multiplexing (OFDM) signal is modulated using the complementary spectral codings of opposite polarity with separate complementary spectral encoded (CSE) optical codes to provide a virtual in-phase (I) and quadrature (Q) (I/Q) multiplexing for the OFDM signal. | 04-09-2009 |
20090245810 | Dynamic Signal Equalization in Optical Transmission Systems - In an optical transmission system, data is transmitted via an optical beam modulated with an arbitrary waveform. The optical beam is transmitted through at least one optical element. Transmission through at least one optical element degrades the signal quality of the initial optical beam. The signal characteristics of at least one optical beam at the output of least one optical element are used as feedback to shape the arbitrary waveform to improve signal characteristics. An arbitrary waveform may be used to compensate signal degradation caused by a multiplexer/demultiplexer in a wavelength division multiplex system. | 10-01-2009 |
20090251345 | PHOTONIC FILTER BANK FOR HIGH-SPEED ANALOG-TO-DIGITAL CONVERSION - An analog to digital converter (ADC) structure and method includes a photonic filter bank having at least two filters. The at least two filters are configured to create a corresponding spectral tributary from an input signal at a target rate, and the at least two filters are configured to exhibit orthogonality properties between respective tributaries. An optical/electrical (O/E) converter is coupled to each of the at least two filters in a respective spectral tributary to convert an optical input to an electrical output. An analog to digital converter (ADC) is coupled to each of the O/E converters in a respective spectral tributary to sample the electrical output at a fraction of a target rate and to convert a sampled analog electrical output into a digital signal. A synthesis filter is coupled to each of the ADCs in a respective spectral tributary to reconstruct the input signal digitally at the target rate. | 10-08-2009 |
20090257344 | ALL OPTICAL OFDM WITH INTEGRATED COUPLER BASED IFFT/FFT AND PULSE INTERLEAVING - A method and apparatus for all optical orthogonal frequency division multiplexing (OFDM) employing Inverse Fast Fourier Transform/Fast Fourier Transform by integrated coupler interferometrically. | 10-15-2009 |
20100054737 | Parallel Optical Polarization Tracking - A system to communicate optical data signals in parallel includes an optical splitter to split the data signals into two polarization multiplexed (PM) signals; and two reception channels coupled to the optical splitter, where each reception channel tracks and isolates a PM signal independently. | 03-04-2010 |
20100086303 | HIGH SPEED POLMUX-OFDM USING DUAL-POLMUX CARRIERS AND DIRECT DETECTION - A polarization multiplexing, orthogonal frequency division multiplexing (POMUX) transmission system utilizing direct detection. | 04-08-2010 |
20120219294 | DIGITAL SIGNAL-TO-SIGNAL BEAT NOISE REDUCTION FOR FILTER-LESS COHERENT RECEIVING SYSTEM - Systems and methods are disclosed for a filter-less coherent receiving system with a filter-less coherent receiver frontend; a signal-signal beat-noise detector coupled to the filter-less coherent receiver frontend; and a real-time processor coupled to the filter-less coherent receiver frontend and the signal-signal beat-noise detector to reject signal-signal interference. | 08-30-2012 |
20120263467 | Polmux-OFDM-DD Transmitter and Receiver for Reduced Complexity and Overhead in Optical Access/Metro Transmission - An optical communication system includes a polarization multiplexed orthogonal frequency-division multiplexing POLMUX-OFDM transmitter for generating a POLMUX-OFDM double sideband signal, an optical processing path for processing the double sideband signal from the transmitter; an analog-to-digital convert ADC-OFDM receiver coupled to the optical processing path for receiving the double sideband signal processed by the optical path; and a block-diagonal multiple-input multiple-output MIMO equalizer responsive to the receiver for enabling correct operation for a completely random incoming signal polarization state without adaptive polarization control at said receiver, which enables complexity. | 10-18-2012 |
20120301142 | Optical Superchannel Method and System - Optical superchannel methods and systems that couple two or more local oscillators into a single coherent receiver front end to receive multiple optical subcarriers are shown and described. With multiple local oscillators coupled into a single coherent receiver and appropriate optical selective filtering of the superchannel signal, non-neighboring subcarriers may be received by the single coherent optical receiver. | 11-29-2012 |
20120321323 | Variable Line-Rate Optical Transmitter by Modulation Format Hopping Using Electrical-Optical-Electrical EOE Generated QAM Signal - The present method is for generating a 4-level optical signal and it includes providing a continuous wave CW optical source; modulating the CW optical source with a first intensity modulator driven by a binary electrical signal a n Gbits/s to generate an optical signal; employing a second intensity modulator as a pulse carving modulator that is driven by an RF signal at n GHz thereby generating a 4 level optical signal for subsequent detection by a receiver. | 12-20-2012 |
20130058648 | Variable Rate Optical Transmitter Based on All-Optical OFDM Super-Channel Technology - The present invention is directed to a method including determining an appropriate power level for a phase modulator for an optimum number of subcarriers; and applying the determined appropriate power level via a controller to produce the optimum number of subcarriers, wherein the optimum number of subcarriers enables an optical-orthogonal frequency division multiplex O-OFDM based variable rate transmitter with automatic control by a controller to produce an optimum setting based on a required rate. | 03-07-2013 |
20130089340 | HIGH-SPEED OPTICAL 8-QAM MODULATION BY CASCADING DUAL-DRIVE MACH-ZEHNDER MODULATOR WITH I/Q MODULATOR - Structures and methods of generating 8-QAM signals through the effect of a cascaded I/Q modulator and Mach-Zhender modulator. The 8-QAM signals are generated by applying one binary sequence to the dual-drive Mach-Zehnder modulator (MZM) and two binary sequences to the I/Q modulator. Operationally, the I/Q modulator generates QPSK constellation(s), while the dual drive MZM either maintains the QPSK constellation at an out ring, or attenuates its amplitude to the inner ring and rotates its phase by π/4 phase depending on the binary data it was driven by. | 04-11-2013 |
20140099127 | Optical Phase Conjugation Aided Long-Haul Transmission System with Enhanced Signal-to-Noise Ratio and Nonlinear Tolerance - A long haul transmission system uses a digital signal processor DSP instead of an additional optical phase conjugate copier because the optical phase conjugate copier requires high quality optical carrier regeneration to recover the pump and optical PLL to maintain phase matching between signal and pump. Therefore, the use of DSP to process the signal and idler at receiver end greatly simplifies the system setup, increases the system stability and decreases the system cost. | 04-10-2014 |
20140314411 | OPTICAL NYQUIST SUPERCHANNEL GENERATION USING MICROWAVE LOW-PASS FILTERING AND OPTICAL EQUALIZATION - Disclosed are structures and methods for generating a Nyquist superchannel. | 10-23-2014 |