Patent application number | Description | Published |
20100092172 | APPARATUS AND METHOD FOR CROSS-CONNECTING OPTICAL PATH IN WAVELENGTH DIVISION MULTIPLEXING SYSTEM - Provided is an optical network in which a wavelength division multiplexing-based optical transmission scheme is implemented. An apparatus for cross-connecting an optical path includes a path switch including a plurality of input terminals receiving optical signals from other nodes, and a plurality of output terminals sending the optical signals to the other nodes, the path switch switching the path of the optical signal so that the optical signal input via one of the input terminals is output to one of the output terminals; and a wavelength converter converting a wavelength of the optical signal input via the input terminal and outputting the wavelength-converted optical signal to the output terminal according to a switching result of the path switch. Thus, inefficient use of a network resource due to wavelength collision can be prevented, the path can be automatically cross-connected and thus quickly established, path switching and branch combination can be performed irrespective of wavelength, and switching can be performed irrespective of direction. | 04-15-2010 |
20100142964 | OPTICAL TRANSMISSION APPARATUS WITH STABLE OPTICAL SIGNAL OUTPUT - An optical transmission apparatus for high-speed optical signal transmission is provided. The optical transmission apparatus includes an optical modulator which includes first and second modulators of a Mach-Zehnder (MZ) interferometer type which are connected in parallel, and an output stabilizer which controls biases for the first modulator, the second modulator and the optical modulator and stabilizes a final output optical signal of the optical modulator. The optical transmission apparatus can perform a stable optical signal output. | 06-10-2010 |
20100142971 | APPARATUS FOR SYNCHRONIZING DIGITAL SIGNALS OF COHERENT OPTICAL RECEIVER - Provided is a digital signal synchronization device of a coherent optical receiver. The digital signal synchronization device includes a digital signal processing unit to perform synchronization on a digital signal of an output optical signal generated by interfering an optical signal received through an optical fiber with an optical signal of laser output from a local oscillator and to perform decoding using the synchronized digital signal, and a digital signal managing unit to monitor the digital signal processing unit to output data of the optical signal normally, which has been received through the optical fiber, according to the synchronized digital signal. | 06-10-2010 |
20100150576 | OPTICAL TRANSMITTING APPARATUS FOR RETURN-TO-ZERO DIFFERENTIAL PHASE-SHIFT-KEYING (RZ-DPSK) OR RETURN-TO-ZERO DIFFERENTIAL QUADRATURE PHASE SHIFT KEYING (RZ-DQPSK) - An optical transmitting apparatus is disclosed. The optical transmitting apparatus outputs a signal having the same phase characteristics as a Return-to-Zero Differential Phase-Shift-Keying (RZ-DPSK) signal by using a single phase modulator. Accordingly, it is possible to generate RZ-DPSK signals without using a separate RZ modulator. | 06-17-2010 |
20100158531 | CHANNEL ASSIGNMENT METHOD AND APPARATUS FOR WAVELENGTH-DIVISION-MULTIPLEXED TRANSMISSION SYSTEM - Provided is a channel assignment method in a wavelength-division-multiplexed transmission system. The channel assignment method includes obtaining information about signal modulation schemes from a plurality of optical transmitters, and assigning channels to the respective optical transmitters in consideration of the obtained information about the signal modulation schemes. Accordingly, in transmission of channels of different modulation formats, cross phase modulation is minimized, thereby reducing inter-channel interference. | 06-24-2010 |
20110008059 | DIGITAL EQUALIZATION APPARATUS AND METHOD FOR COHERENT OPTICAL RECEIVER - Disclosed are a digital equalization apparatus for a coherent optical receiver and a digital equalization method for a coherent optical receiver, capable of compensating for chromatic dispersion and polarization impairment through a digital signal processing, and capable of performing a clock recovery and a data recovery through a digital symbol synchronization. The digital equalization apparatus and the method compensate for various impairments occurring on an optical path in a digital manner and achieve synchronization through a simple structure. | 01-13-2011 |
20110026924 | OFDM OPTICAL TRANSMITTER AND OPTICAL TRANSMISSION METHOD - An OFDM optical transmitter and optical transmission method is provided. The OFDM optical transmitter includes a signal converter controlling amplitude of each of data signals according to a position of each of the data signals and converting the controlled data signal into a time-domain signal. Accordingly, it is possible to generate optical OFDM carriers which are uniform in size. | 02-03-2011 |
20110090992 | OFDM RECEIVER AND METHOD FOR COMPENSATING FOR I/Q IMBALANCE - An OFDM receiver for compensating for I/Q imbalance is provided. The OFDM receiver includes an I/Q demodulator demodulating a received signal into a baseband in-phase (I) channel signal and a baseband quadrature (Q) channel signal, and an I/Q imbalance compensator compensating for imbalance between the I-channel signal and the Q-channel signal in a time domain. Accordingly, it is possible to solve the I/Q imbalance and suppress degradation in the performance of the OFDM communication device. | 04-21-2011 |
20120020676 | APPARATUS FOR RECEIVING OPTICAL SIGNAL AND METHOD OF CONTROLLING PHASE OFFSET FOR DIFFERENTIAL QUADRATURE PHASE SHIFT KEYING - An apparatus for receiving optical signals in DQPSK and method of controlling a phase offset in receiving optical signals for DQPSK is provided. An original optical signal modulated in DQPSK is received. The original optical signal is delayed by one bit to make a delay optical signal such that an interference on the original optical signal and the delay optical signal is performed. A control signal is generated by use of an interference result between the original optical signal and the delay optical signal. A phase offset for the interference between the original optical signal and the delay optical signal is controlled by use of the generated control signal. In receiving optical signals, the phase offset between the delay optical signal and the original optical signal is precisely controlled, thereby optimizing the transfer characteristics of an optical delay interferometer. | 01-26-2012 |
20120148265 | COHERENT OPTICAL RECEIVING DEVICE CAPABLE OF DIGITAL EQUALIZATION OF OPTICAL INPUT, DIGITAL EQUALIZATION METHOD FOR OPTICAL INPUT AND COHERENT OPTICAL TRANSMITTING/RECEIVING DEVICE - A coherent optical receiving device capable of digital equalization of an optical input, and a method thereof. The coherent optical receiving device includes a chromatic dispersion compensating unit configured to comprise a filter for chromatic dispersion compensation and compensate for chromatic dispersion with respect to a digital signal that corresponds to an optical input using the filter; a decoder configured to generate a bit sequence of the signal which has been compensated for chromatic dispersion; a bit error calculating unit configured to calculate a bit error amount in the bit sequence; and a controller configured to monitor the bit error amount, determine a filter coefficient that makes the bit error amount a minimum, and set the determined filter coefficient in the chromatic dispersion compensating unit. | 06-14-2012 |
20140199075 | APPARATUS AND METHOD FOR CONTROLLING MULTICARRIER LIGHT SOURCE GENERATOR - An apparatus and method for controlling a multicarrier light source generator are provided. The apparatus includes N-light source input units configured to input light sources to a multicarrier light source generator that generates multicarrier light sources at a frequency interval of F [Hz], and a control unit configured to adjust the frequency interval of the multicarrier light sources generated from the multicarrier light source generator, by adjusting a frequency interval between the light sources input from the N-light source input unit as F/N [Hz]. | 07-17-2014 |
20140294401 | OPTICAL TRANSMITTER AND METHOD THEREOF - An optical transmitter including an optical modulator comprising a first modulator and a second modulator connected in parallel to each other in the form of a Mach-Zehnder interferometer, and a phase shifter connected to the second modulator in series, a high-speed generator configured to generate a single carrier signal or multi-carrier signals and apply the generated single carrier signal or multi-carrier signals to the optical modulator, and an output stabilizer configured to stabilize a final output optical signal of the optical modulator by controlling a bias of each of the first modulator, the second modulator and the phase shifter. | 10-02-2014 |