Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An optical add/drop multiplexer includes a multiplexing/demultiplexing unit having an input multiplexing port, an output multiplexing port and a plurality of demultiplexing ports each connected to a respective optical circulator. Each optical circulator includes a first port for internally inputting an added channel, a second port for outputting the added channel to a corresponding demultiplexing port and receiving a channel outputted by the corresponding demultiplexing port, and a third port for outputting the channel received from the second port.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An optical add/drop multiplexer for adding or dropping a channel to an optical signal. The optical add/drop multiplexer includes a wavelength-division multiplexer to receive and transmit an optical signal, and a plurality of demultiplexing ports, each demultiplexing port is a path for a demultiplexed channel of the optical signal; and a plurality of add/drop multiplexers, wherein respective add/drop multiplexers are connected to respective demultiplexing ports, each of the add/drop multiplexers having a reflector for transmitting or reflecting an input channel, wherein each add/drop multiplexers is configured to add and/or drop a channel to/from from the wavelength-division multiplexer using the reflector.

Abstract: A PON (Passive Optical Network) and method employing CDMA for upstream communications to avoid complicated systems such as Machine Access Control. The downstream communications are broadcast in a non-CDMA protocol such as TDM.

Abstract: An optical switching device has a plurality of input ports, and a plurality of output ports, that uses only circulators and reflectors to perform optical switching. A plurality of circulators each having a plurality of ports while operating to output an optical signal are input to a higher-order port thereof, to a lower-order port thereof arranged adjacent to the higher-order port. Each of the circulators being connected at a highest-order port thereof to an associated one of the input ports, at a lowest-order port thereof to an associated one of the output ports, and at each intermediate port thereof to a corresponding intermediate port of another one of the circulators. A plurality of reflectors each of which is adapted to reflect an optical signal, inputted thereto, or to allow the optical signal to pass there through. Each of the reflectors being connected between two intermediate ports of every two of the circulators connected to each other at the two intermediate ports.

Abstract: 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.

Abstract: 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.

Abstract: 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×N demultiplexer and a 1×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.

Abstract: 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.

Abstract: 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.

Abstract: Disclosed is a system and method for supplying driving power to media converters for optical communication, which can realize a communication system employing a simple circuit construction at a minimal expense even in the case where the communication system includes a plurality of media converters. Each media converter converts an interface of an electrical-communication device to an interface of an optical-communication device and converts the interface of the optical-communication device to the interface of the electrical-communication device. The system includes: a power-supply device constructed independently from the media converters; and, at least one power-supply socket device to supply power from the power-supply device to the media converters.

Abstract: An optical cross-connect system is disclosed that use reduces the number of AWGs (Arrayed-Waveguide Grating) as compared to prior art systems so that the hardware complexity is reduced while simultaneously reducing its production costs. The optical cross-connect system includes N×N AWGs for performing multiplexing/demultiplexing functions, an optical circulator for transmitting bidirectional signals via the AWGs, an optical coupler for interconnecting N individual ports of the AWGs, and an optical switching block connected to the optical coupler. One of the optical signals branched from the optical coupler is input to the optical switching block having a corresponding wavelength and distributed to a desired output terminal, and the other one of the optical signals is input to an optical switching block being out of an operable wavelength range and filtered by the optical switching block.

Abstract: There is disclosed an optical source generator for wavelength division multiplexing optical communication systems.

Abstract: 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.