Samsung Electronics Co., Ltd.

Other

Jong-Kwon Kim

Ki-Cheol Lee

Yun-Je Oh

Jun-Ho Koh

Seong-Taek Hwang

Sang-Hyun Doh

Jong-Hun Lee

Se-Kang Park

Hak-Phil Lee

Tae-Sung Park

Jun-ho Koh

Chan-yul Kim

Sang-Il Lee

Disclosed is a method for estimating an available bandwidth of a network. A plurality of periodic time-stamp packets are transmitted to a receiving-party communication apparatus, which is connected to the network, through the network at a currently-set test transmission rate, and then a changing tendency of transmission delay time differences between the time-stamp packets is checked on the basis of reception times at which the receiving-party communication apparatus have received the respective time-stamp packets. When the transmission delay time differences are located outside a stable range and show a tendency to increase, the test transmission rate is set to a decreased value and the time-stamp packets are repeatedly transmitted at the decreased rate and when the transmission delay time differences are located outside the stable range and show a tendency to decrease, the test transmission rate is set to be an increased value and the time-stamp packets are repeatedly transmitted at the increased rate. A test transmission rate is determined as the available bandwidth when the transmission delay time differences are within the stable range.

Method for estimating available bandwidth of network

A large-capacity optical router is disclosed that exchanges data traffic such as IP packets, Ethernet frames, etc., at high speed in units of optical frames. The large-capacity optical router uses an electric buffer including input ports, output ports, an add port for inputting data received from a lower IP router, a drop port for outputting data to the lower IP router, a wavelength division demultiplexing section for wavelength-division-demultiplexing wavelength signals input through the input ports and the add port, an input interface section for converting optical frames from the wavelength division demultiplexing section into electric signals, and an optical switch for performing a high-speed switching of the optical frames from the input interface section. The large-capacity optical router also includes an output interface section for processing the optical frames output from the optical switch, a wavelength division multiplexing section for wavelength-division-multiplexing outputs of the output interface section and transmitting the multiplexed outputs to another large-capacity optical router, a drop interface section for processing the optical frames from the wavelength division multiplexer to the lower IP router, a header processing section for recognizing header information, an optical switch control section for controlling a connection state of the optical switch, a header reinserting section for reinserting headers into outputs of the optical router, and an edge traffic aggregator including of an ingress part for converting IP packets input from the lower IP router into optical frames and an egress part for converting the optical frames into IP packets and transmitting the converted packets to the IP router.

Large-capacity optical router using electric buffer

An optical source generator for wavelength-division-multiplexing optical communication systems includes a wavelength-division multiplexer/demultiplexer, optical amplifiers, and wavelength-dependent reflectors such as optical fiber-Bragg gratings or wavelength-independent reflectors such as mirrors, so as to form laser resonant cavities. Lasing of the optical fibers therefore generates spontaneously emitted lights. Further, the optical source generator controls each reflectance of the respective wavelength-dependent or independent reflectors so that lights amplified within the laser resonant cavities can be used as multi-wavelength optical sources or independent optical sources.

Optical source generator for wavelength division multiplexing optical communication systems

A bi-directional wavelength division multiplexing self-healing optical ring network is disclosed, in which N optical signals are processed at both first and second ring network so that a protection switch mechanism is performed when a link failure occurs in any one of the first and second ring networks. The bi-directional WDM self-healing optical ring network includes a plurality of nodes having optical add/drop multiplexers, each being provided on the first and second ring networks and further including a demultiplexer and a multiplexer, each of which has a capacity of 1&#xd7;N; a pair of switching devices provided across the first and second ring networks and connected between the optical add/drop multiplexers and fiber optic links connected with another node; and, wavelength interleavers, each being provided on both ends of each optical add/drop multiplexer provided on the first and second ring networks, includes three ports, of which one port is connected to each switching device and allows for passing signals of all wavelength bands, another port allows for passing only signals of some wavelength bands processed on any one of the first and second ring networks, and the third port allows for passing only signals of the other wavelength bands processed on the other.

Bi-directional wavelength division multiplexing self-healing optical ring network

A PON and a method of transmitting data employing different upstream and downstream transmission protocols are disclosed. The PON includes: a plurality of ONTs; WDM filters; an OLT receiving and transmitting optical signals to and from the ONTs and a higher network; and an optical coupler. The ONT includes a first switching unit, a level transformer converting two level Ethernet signals into a three level data signals, a first code generator generating a specific CDMA codes that distinguish the ONT from another ONT, and a first multiplier performing a spread spectrum function with the CDMA codes. The OLT includes an optical receiver, a branching filter branching the upstream CDMA signals, a plurality of second code generators generating codes for despread, a plurality of second multipliers multiplying the received signals by the despread codes, and a plurality of data decider extracting data through correlation calculation.

Passive optical network employing code division multiple access

Disclosed is an optical cross-connect device for communication between first and second optical networks communicating with each other using forward and backward optical signals each including of a plurality of channels. The device includes a first circulating part having first through fourth ports configured to output an optical signal, which is input to a higher-order port thereof, from a lower-order port thereof arranged adjacent to the higher-order port. The first circulating part is connected at the first and third ports thereof to a first optical network. A second circulating part has first through fourth ports configured to output an optical signal, which is input to a higher-order port thereof, from a lower-order port thereof arranged adjacent to the higher-order port. A first reflecting part is connected to respective second ports of the first and second circulating parts, and adapted to selectively reflect each channel of a forward optical signal which is input thereto or allow the channel to pass therethrough, and a second reflecting part is connected to respective fourth ports of the first and second circulating parts, and adapted to selectively reflect each channel of a backward optical signal which is input thereto or allow the channel to pass therethrough.

Bi-directional optical cross-connect device

A high speed optical routing apparatus and method, in which data traffic, such as an IP packet, an Ethernet frame, etc., is switched in an optical frame unit at a high speed. The apparatus is provided with a plurality of input and output ports, and with one add port for adding data received from a lower IP router, and one drop port for dropping processed data toward the lower IP router. A header wavelength dividing unit extracts the header wavelength signals from among input optical signals inputted through the input ports and the add port. The header wavelength signals contain header information on data wavelength signals contained in the input optical signals. An optical signal inputting section demultiplexes optical signals having the data signals according to the wavelength, and for dividing and inputting the wavelength-based demultiplexed data wavelength signals according to a frame. The data wavelength signals are divided with the header wavelength signals through the header wavelength dividing section, an optical switch for switching the frame-based divided optical signals outputted from the optical signal inputting, an optical signal outputting section for combining the frame-based divided optical signals switched and outputted at the optical switch, for wavelength-multiplexing the combined optical signals into one output optical signal and for outputting the multiplexed output optical signal, a controlling section for controlling the optical signal inputting section, the optical switch and the optical signal outputting section.

High speed optical routing apparatus and method

Disclosed is a bi-directional optical add/drop multiplexer connected to an optical fiber for transmitting optical signals multiplexed in a wavelength division multiplexing optical network and which performs adding/dropping of the optical signals. The optical add/drop multiplexer includes a first wavelength division multiplexer provided with a multiplexing port functioning as a path for forward or backward optical signals and with a plurality of demultiplexing ports, each functioning as a path of demultiplexed channels. A plurality of add/drop parts, each performing adding/dropping of preset channels, and connected with the demultiplexing ports of the first wavelength division multiplexer in one-to-one. A second wavelength division multiplexer connected with the plurality of add/drop parts in one-to-one, provided with a plurality of demultiplexing ports, each functioning as a path for demultiplexed channels and with a multiplexing port functioning as a path for forward or backward optical signals. The first wavelength division multiplexer has a free spectral range equal to that of the second wavelength division multiplexer, in which a wavelength band of the forward optical signals is included in the free spectral range having one period, while a wavelength band of the backward optical signals is included in the free spectral range having another period.

Bi-directional optical add/drop multiplexer for WDM optical networks

A passive optical network (PON) for providing a large amount of data at high speed to subscribers is provided. In particular, a PON employing a multi-carrier CDMA in which a CDMA method is applied for an upstream signal is provided. The PON employing a multi-carrier CDMA includes: optical network terminals (ONTs) for transmitting CDMA-based data using multiple carriers to an optical line terminal (OLT) and for receiving Ethernet-based data transmitted from the OLT; the OLT for transforming CDMA-based data received from the ONT into Ethernet-based data, for transmitting the Ethernet-based data to a higher network, and for transmitting Ethernet-based date to the ONTs; and an optical coupler for coupling CDMA-based optical signals transmitted from the ONTs, for transmitting the coupled optical signal to the OLT, and for distributing an Ethernet-based optical signal transmitted from the OLT to the ONTs.

Passive optical network employing multi-carrier code division multiple access

A multi-wavelength light source unit for optical communication system is disclosed. The light source includes a demultiplexer for demultiplexing a multiplexed light signal into a plurality of lights having different wavelengths and a multiplexer that receives the demultiplexed lights and multiplexes the demultiplexed lights into the multiplexed light signal. Input ports of the multiplexer are respectively port-to-port connectable to each one of a plurality of output ports of the demultiplexer. The light source unit includes a plurality of semiconductor optical amplifiers amplifying the demultiplexed lights output form the demultiplexer, and a plurality of beam splitters for splitting the amplified demultiplexed lights into two parts, so as to provide the respective input ports of the multiplexer with a split part of the lights, while to transmit the other part of the lights out of the beam splitters.

Multi-wavelength light source

A passive optical network includes a central office and a subscriber-side apparatus connected with the central office through an optical fiber link. The subscriber-side apparatus performs communication with the central office based on wavelength-division-multiplexed optical signals. The central office has a routing section, provided with first to fourth multiplexing ports, for demultiplexing multi-wavelength light inputted from the fourth multiplexing port into a plurality of channels. Each of the demultiplexed channels is amplified and multiplexed for output through the first multiplexing port. Optical signals inputted through the third multiplexing port are demultiplexed and outputted upstream. The routing section also multiplexes channels for downstream optical signals, outputting the multiplexed channels through the second port. A splitting section, provided with first to third splitting ports and arranged on a loop optical waveguide connects the first and fourth multiplexing port with each other. The splitting section causes some of multi-wavelength light inputted into the first splitting port to be outputted through the second splitting port and causes the remainder of multi-wavelength light to be outputted through the third splitting port connected with the fourth multiplexing port. A circulator causes the multi-wavelength light inputted through the second splitting port to be transmitted to the subscriber-side apparatus and causes upstream optical signals received from the subscriber-side apparatus to be outputted to the third multiplexing port.

Passive optical network using loop back of multi-wavelength light generated at central office

A wavelength-path-monitoring/correcting apparatus used in a transparent OXC is disclosed. The apparatus includes: a path-information-generating section for generating path-monitoring information; a plurality of optical couplers for coupling each output signal of the wavelength-division demultiplexers with the pertinent path-monitoring information; a plurality of optical switches for switching each optical signal inputted from the optical couplers; a plurality of wavelength-division multiplexers for multiplexing optical signals inputted through the optical switches; a path-information-detecting section for detecting the path-monitoring information from optical signals outputted from the wavelength-division multiplexers; and, a path-control section for comparing the path-monitoring information detected through the path-information-detecting section with predetermined optical-switching information and for correcting switched paths.

Wavelength path monitoring/correcting apparatus in transparent optical cross-connect and method thereof

A wideband erbium-doped optical fiber amplifier is disposed among an optical fiber through which a first and second band-band optical signals (for example, the C-band and L-band) are transmitted and forms a first optical path and a second optical path parallel to each other. The wideband erbium-doped optical fiber amplifier comprising a first amplifying section disposed on the first optical path, including a first erbium-doped optical fiber to amplify the first-band optical signals, a filter to gain-flatten the amplified first-band optical signals, wherein a reflected portion of the first band optical signal by the filter is directed to the second optical path; and a second amplifying section disposed on the second optical path, having a second erbium-doped optical fiber to amplify received second-band optical signals, wherein the reflected first-band optical signal is used to pump the second erbium-doped optical fiber.

Gain-flattened wideband erbium-doped optical fiber amplifier

A bidirectional WDM self-healing ring network is provided and includes an outer ring network and an inner network for processing N units of optical signals and for performing a protection switching by using the outer ring network when the inner ring network suffers a link failure.

Bidirectional WDM self-healing ring network

A WDM bidirectional self-healing optical ring network is provided in which an outer ring network and an inner ring network can both handle N optical signals. The network includes a node; an optical add/drop multiplexer having a 1&#xd7;N demultiplexer and a 1&#xd7;N multiplexer; a pair of optical switching devices each connected to an optical fiber link intervening between the optical add/drop multiplexer and another node on the both ends of the optical add/drop multiplexer; and, a pair of circulators each connected between the optical add/drop multiplexer and a particular optical switching device in the optical switching device pair, each circulator having three ports, two of the three ports being connected to a corresponding optical switching device and remaining one port being connected to the optical add/drop multiplexer.

Growing community of inventors

Taejonkwangyok-shi, South Korea

Jong-Kwon Kim