Patent application number | Description | Published |
20100002881 | POLARIZATION-INSENSITIVE ONE-WAY QUANTUM KEY DISTRIBUTION RECEIVER, TRANSMITTER/RECEIVER SYSTEM - Provided are an apparatus for receiving a quantum cryptographic key and an apparatus for transmitting and receiving a quantum cryptographic key at high speed without polarization drift of an optical pulse signal and phase drift of an interferometer. The apparatus for receiving a quantum key includes: a polarization-insensitive optical phase modulator parts for receiving an optical pulse signal, and modulating and outputting a phase of the optical pulse signal without being affected by the polarization state of the optical pulse signal; an asymmetric Mach-Zehnder interferometer for causing interference in and outputting the optical pulse signal received from the polarization-insensitive optical phase modulator parts; and a photon detectors for detecting the optical pulse signal received from the asymmetric Mach-Zehnder interferometer. According to the apparatuses, it is possible to perform quantum cryptography communication at high speed without being affected by polarization drift of an optical pulse signal and phase drift of an interferometer. | 01-07-2010 |
20100158252 | POLARIZATION CODING QUANTUM CRYPTOGRAPHY SYSTEM - Provided is a polarization coding quantum cryptography system. The quantum cryptography includes a light source, a quantum channel, an optical path selector, and a path-dependent polarization selector. The light source generates a signal light. The quantum channel is used as a path to transmit the signal light to a receiver unit. The optical path selector is disposed between the light source and the quantum channel to transmit the signal light to one of a plurality of propagation paths. The path-dependent polarization selector is disposed between the optical path selector and the quantum channel. Herein, the path-dependent polarization selector is configured to determine the polarization direction of the signal light according to the propagation path of the signal light. | 06-24-2010 |
20110064422 | POLARIZATION SPLITTER, OPTICAL HYBRID AND OPTICAL RECEIVER INCLUDING THE SAME - Provided is an optical receiver used for an optical communication system, more particularly, a polarization split-phase shift demodulation coherent optical receiver. An optical hybrid includes a first optical splitter, a phase shift waveguide, a second optical splitter, and an optical coupler. The first optical splitter splits a first input optical signal to output first output optical signals. The phase shift waveguide receives the first output optical signals and controls and outputs the first output optical signals such that the first output optical signals have different phases. The second optical splitter splits a second input optical signal to output a plurality of second output optical signals. The optical coupler couples the first output optical signals one-to-one with the second output optical signals, respectively. | 03-17-2011 |
20110096855 | POLARIZATION DIVISION MULTIPLEXED OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING TRANSMITTER AND RECEIVER - Provided is a polarization division multiplexed optical OFDM transmitter. The polarization division multiplexed optical OFDM transmitter includes a data demultiplexer, a training symbol generation unit and an optical up-converter and polarization division multiplexing unit. The data demultiplexer divides a transmission signal into a plurality of groups. The training symbol generation unit allocates a plurality of training symbols for each OFDM data which is included in the respective multiplexed groups, and allocates repetitive data in a time domain for the respective training symbols for data of 0 to periodically appear for the respective training symbols in a frequency domain. The optical up-converter and polarization division multiplexing unit performs optical frequency band conversion and polarization division multiplexing on an output of the training symbol generation unit to output a polarization division multiplexed optical OFDM signal corresponding to a plurality of polarization components. | 04-28-2011 |
20110135319 | OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING RECEIVER AND OPTICAL SIGNAL RECEIVING METHOD THEREOF - Provided is an optical OFDM receiver. The optical OFDM receiver receives an optical signal dependent on the nonlinearity of a transmitter. The optical OFDM receives includes an optical down converter, a nonlinearity compensator, and an OFDM demodulator. The optical down converter converts the optical signal into an electrical signal. The nonlinearity compensator filters the electrical signal, for compensating distortion which is added to the optical signal when the transmitter performs optical modulation. The OFDM demodulator demodulates the distortion-compensated electrical signal in an OFDM scheme. | 06-09-2011 |
20110142398 | ADAPTER ASSEMBLY AND METHOD FOR COMPENSATING OPTICAL FIBERS FOR LENGTH DIFFERENCE - Provided are an adapter assembly and method for compensating optical fibers for a length difference. The adapter assembly includes a first adapter, a second adapter, and a member. The first adapter is configured to be connected to at least one optical communication unit. The second adapter is configured to be connected to at least another optical communication unit and be coupled to the first adapter. The member is configured to be interposed between the first and second adapters for providing an optical signal transmission path between the optical communication units. Owing to the member, a length difference between optical fibers can be compensated for. | 06-16-2011 |
20120114293 | OPTICAL WAVEGUIDE STRUCTURE HAVING ANGLED MIRROR AND LENS - The present disclosure relates to a planar optical waveguide element, and more particularly, to an optical waveguide end structure for effective optical signal connection with a light source, a light receiving element, or a different type of optical waveguide element. | 05-10-2012 |
20120132792 | OPTICAL MODULE COMPRISING OPTICAL HYBRID USING METAL OPTICAL WAVEGUIDE AND PHOTO DETECTOR - An exemplary embodiment of the present disclosure provides an optical module including: an optical hybrid including a metal optical waveguide; a photo detector configured to receive light; and a platform including an optical hybrid supporting section for supporting the optical hybrid, a photo detector supporting section for supporting the photo detector, and an inclined surface configured to change a propagation direction of light emitted from the optical hybrid, and configured to combine the optical hybrid and the photo detector. | 05-31-2012 |
20120155887 | METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING COHERENT OPTICAL OFDM - Disclosed are a method and an apparatus for transmitting and receiving coherent optical OFDM. The apparatus includes: a transmitted OFDM digital signal processing unit outputting an in-phase (I) component digital signal and a quadrature phase (Q) component digital signal; a digital-analog converter converting the in-phase (I)-component digital signal and the quadrature-phase (Q)-component digital signal into an in-phase (I)-component analog signal and a quadrature-phase (Q)-component analog signal, respectively; an adder adding an additional pilot tone signal to each of the in-phase (I)-component analog signal and the quadrature-phase (Q)-component analog signal outputted from the digital-analog converter; and an optical I/Q modulator up-converting the in-phase (I)-component analog signal added with the additional pilot tone signal and the quadrature-phase (Q)-component analog signal added with the additional pilot tone signal to an optical domain to output a coherent optical OFDM signal including the additional pilot tone signal. | 06-21-2012 |
20130156362 | CORE AND OPTICAL WAVEGUIDE - Provided is a core which reduces optic splice loss between discontinuous optical waveguides. The core includes a first waveguide propagation portion having first light-receiving width, a first lightwave discontinuous portion having second light-receiving width, a first taper structure portion having both ends connected to the first lightwave propagation portion and to the first lightwave discontinuous portion, respectively and decreasing in light-receiving width as it goes from the first lightwave propagation portion to the first lightwave discontinuous portion, a second lightwave propagation portion having third light-receiving width, a second lightwave discontinuous portion having fourth light-receiving width, and a second taper structure portion having both ends connected to the second lightwave propagation portion and to the second lightwave discontinuous portion, respectively and decreasing in light-receiving width as it goes from the second lightwave propagation portion to the second lightwave discontinuous portion. | 06-20-2013 |
20130156394 | OPTICAL COMMUNICATION MODULE AND METHOD OF MANUFACTURING THE SAME - The inventive concept relates to an optical communication module. The optical communication module may include a metal block: an electrical device formed on the metal block; an optical device adhesive block formed on the metal block; an optical device formed on the optical device adhesive block and connected to the electrical device through a bonding interconnection; and a flat type optical waveguide formed on one side of the optical device adhesive block and optically aligned with the optical device. | 06-20-2013 |
20130156424 | APPARATUS FOR MEASURING PERFORMANCE OF COHERENT OPTICAL RECEIVER - An apparatus for measuring performance of a coherent optical receiver includes a beam splitter splitting light into first and second paths, a first optical modulator modulating the first path light, a variable optical attenuator controlling an optical power of the first optical modulator, a first polarization controller transmitting a signal controlling polarization of an output of the variable optical attenuator to the coherent optical receiver, a second optical modulator modulating the second path light, a variable optical delay line delaying time of an output of the second optical modulator, a second polarization controller transmitting a signal controlling polarization of an output of the variable optical delay line to the coherent optical receiver, a network analyzer measuring performance of the coherent optical receiver and controlling the optical modulators, and a controller transmitting a control signal to the optical modulators. | 06-20-2013 |
20130308949 | OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLE MULTIPLEXING RECEIVER AND OPTICAL SIGNAL RECEIVING METHOD THEREOF - Provided is an optical OFDM receiver. The optical OFDM receiver receives an optical signal dependent on the nonlinearity of a transmitter. The optical OFDM receives includes an optical down converter, a nonlinearity compensator, and an OFDM demodulator. The optical down converter converts the optical signal into an electrical signal. The nonlinearity compensator filters the electrical signal, for compensating distortion which is added to the optical signal when the transmitter performs optical modulation. The OFDM demodulator demodulates the distortion-compensated electrical signal in an OFDM scheme. | 11-21-2013 |
20140169786 | APPARATUS AND METHOD FOR MEASURING IQ IMBALANCE FOR OPTICAL RECEIVER - Provided is an apparatus and method for measuring IQ imbalance, and in particular, is an apparatus and method for measuring IQ imbalance for an optical receiver. The apparatus for measuring IQ imbalance for an optical receiver includes a light generating unit generating optical and reference signals to provide the optical and reference signals to an optical receiver, a graph creating unit creating a Lissajous figure by using an in-phase (I) signal and a quadrature-phase (Q) signal output from the optical receiver in response to the optical and reference signals, and a calculating unit calculating IQ imbalance for the optical receiver with reference to the Lissajous figure. | 06-19-2014 |
20140205280 | MEASURING DEVICE AND METHOD OF MEASURING SIGNAL TRANSMISSION TIME DIFFERENCE THEREOF - Provided is a method of measuring signal transmission time difference of a measuring device. The measuring device according to embodiments, by measuring a skew on two optical paths through signal delays of sufficient sizes for skew measurement on the optical paths, even a skew having a minute size can be measured within a measureable range. | 07-24-2014 |