Abstract: A light source apparatus for use with optical communication using external-injection light sources, and an optical communication system using the light source apparatus. The light source apparatus for optical communication includes external-injection light sources, and a multiplexer/demultiplexer. The multiplexer/demultiplexer provides light components spectrum-sliced broadband light from a broadband light source as respective external injection light inputs. The multiplexer/demultiplexer includes a first waveguide to transmit the broadband light and multiplexed light with a plurality of wavelengths, a plurality of second waveguides each to transmit light with an associated one of the wavelengths, and a plurality of optical filters each to pass light with an associated one of the wavelengths and to reflect the remaining wavelengths.

Abstract: Disclosed is a method for maintaining wavelength-locking of a Fabry-Perot laser regardless of a change of external temperature even though a temperature controller is not used, and a wavelength division multiplexing (WDM) light source using the method, as an economical light source used in a WDM optical communication field. The WDM light source comprises a Fabry-Perot laser for injecting spectrum-spliced incoherent light to amplify and output only an oscillation mode matching with a wavelength of the injected light, and a bias controlling unit for adjusting a bias current supplied to the Fabry-Perot laser to a value adjacent to a threshold current of the Fabry-Perot laser, whose threshold current is changed according to a temperature and a relationship between the injected light changed depending to a temperature and a wavelength of the oscillation mode.

Abstract: A wavelength-division-multiplexed light source for transmitting broadband light through a fiber and receiving an optical signal through the fiber is disclosed. The wavelength-division-multiplexed light source includes: a light source for outputting broadband light; and a coupler for outputting the broadband light, which has been input from the light source, to the fiber through cross coupling, and outputting an optical signal, which has been input from the fiber, through bar coupling, based on a predetermined cross coupling ratio, wherein the cross coupling ratio of the coupler is adjusted depending on a power of the optical signal.

Abstract: A bidirectional add/drop multiplexer includes first input/output unit inputs a first optical signal multiplexed from a plurality of odd channels and outputs a second optical signal multiplexed from a plurality of added or dropped even channels; a second input/output unit outputs the first optical signal multiplexed from a plurality of added or dropped odd channels and outputs the second optical signal multiplexed from a plurality of even channels; an optical arrayed waveguide grating for multiplexing added or dropped odd channels of the first optical signal input to a first terminal for subsequent transmission to the second input/output unit, multiplexing added or dropped even channels of the second optical signal input to a second terminal for subsequent transmission to the first input/output unit; and an optical combining unit that amplifies the first optical signal and the second optical signal input from the first input/output unit and the second input/output unit.

Abstract: Disclosed is a Fabry-Perot laser device connected with an optical transmission link. The device comprises an optical circulator for forming an optical waveguide loop and circulating light through the optical waveguide loop and for outputting light from the optical waveguide loop through an external port; an optical fiber amplifier located on the optical waveguide loop and for amplifying the light circulating in the optical waveguide loop; a laser light source connected with the exterior port and being self-seeded by the light inputted through the exterior port and for outputting wavelength-locked light to the exterior port; and, a first splitter located on the loop for splitting a portion of the circulating light and for outputting the split-off light to the optical transmission link.

Abstract: A wavelength division multiplexed light source for a passive optical network using the same includes broadband light sources arranged at a desired interval on a wavelength axis, so as to output wavelength bands each having a plurality of structural wavelengths. Further included is a main coarse wavelength division multiplexer (M-CWDM) for multiplexing the lights and a dense wavelength division multiplexer (DWDM) for spectrally dividing the multiplexed light into the channels corresponding to structural wavelengths of the multiplexed light. Groups are consequently generated each of which has a plurality of channels spaced at wavelength period.

Abstract: A method for maintaining the mode-locked state of a Fabry-Perot (FP) laser and a WDM light source using the same method for use in WDM optical communication are disclosed. The mode-locked state can be maintained irrespective of temperature change, without use of a temperature controller, by spectrum-slicing the incoherent light generated by a light source element and injecting the spectrum-sliced light to the FP laser, then the FP laser amplifies and outputs only a lasing mode coinciding with the wavelength of the injected light, wherein a lasing-mode interval of the FP laser is set to be less than a 3 dB linewidth of the injected light, so that at least one lasing mode exists inside the 3 dB linewidth of the injected light irrespective of changes in external temperature.

Abstract: A SCM-PON using WDM includes: an OLT for transferring downstream data from an external service provider through downstream optical signals and transferring upstream data transferred through upstream optical signals to an outside; an ODN for distributing the downstream optical signals from the OLT and multiplexing the upstream optical signals to the OLT; and a plurality of ONUs for processing the downstream optical signals transferred from the OLT through the ODN and transferring upstream data of subscribers for the OLT through the upstream optical signals, wherein the optical signals between the OLT and the ONUs are divided into wavelength channels with different wavelengths and sub-carrier channels obtained by time-dividing the wavelength channels, and the upstream data and the downstream data are transferred through the sub-carrier channels.

Abstract: Disclosed is an optical semiconductor device that provides an optical gain or optical loss depending on application of electric current. The optical semiconductor device comprises: a lower clad layer; an active layer disposed on the lower clad layer, the active layer generating optical gain or optical loss depending on injection of carriers; an upper clad layer disposed on the active layer, the upper clad layer serving to trap light in the active layer in cooperation with the lower clad layer; and a temperature control part for controlling the temperature distribution of the active layer along the light propagation axis in such a manner that temperature of the active layer varies depending on positions in the active layer.

Abstract: Disclosed is a method for removing cross-talk in a wavelength division multiplexed passive optical network (WDM-PON). The WDM-PON and the method remove cross-talk between adjacent wavelength channels due to incomplete alignment of wavelength channels in a MUX/de-MUX between a central office and a remote node in the WDM-PON employing light-injected light sources. The WDM-PON includes at least two broadband light sources having different bands, which provide injection light to be injected to light-injected channels light sources, a transmitter receiving injection from the broadband light sources, injecting the injection light to odd channel light-injected light sources and even channel light-injected light sources, arraying odd and even channels in such a manner that the odd and even channels belong to different spectrum bands, multiplexing the signal according channels, and transmitting the multiplexed signal.

Abstract: Disclosed is a self-healing passive optical network comprising: a station, such as a central office, for outputting first and second multiplexed downstream optical signals to first and second feeder fibers; a remote node connected to the central office through the first and second feeder fibers to demultiplex each input multiplexed downstream optical signal into a plurality of downstream optical signals and to output the demultiplexed downstream optical signals; and a plurality of optical network units for receiving one or more downstream optical signals, each of the optical network units are connected to the remote node through at least one distribution fiber, wherein the station outputs the first and second multiplexed downstream optical signals to the first and second feeder fibers, respectively, and outputs the first and second multiplexed downstream optical signals to one of the first and second feeder fibers when a defect occurs in a fiber.

Abstract: Disclosed are an optical transceiver and an passive optical network using the same. The optical transceiver includes a polarization splitter for splitting injected light input from an outside of the optical transceiver into a first polarization component and a second polarization component, a light injected transmitter for receiving the first polarization component and outputting an optical signal generated based on the first polarization component, and an optical receiver for detecting an electrical signal based on the second polarization component.

Abstract: Disclosed are an optical transceiver and an passive optical network using the same. The optical transceiver includes a polarization splitter for splitting injected light input from an outside of the optical transceiver into a first polarization component and a second polarization component, a light injected transmitter for receiving the first polarization component and outputting an optical signal generated based on the first polarization component, and an optical receiver for detecting an electrical signal based on the second polarization component.

Abstract: Disclosed is a method for operating a wavelength-division-multiplexed passive optical network (WDM-PON) including an optical line terminal (OLT) and a plurality of optical network units (ONUs), each of which is connected to the OLT and communicates with the OLT. The method comprises the steps of transmitting a first control channel including allocation information of downstream data channels and allocation information of time slots for the downstream data channels to each of the plurality of ONUs; and transmitting downstream data to the plurality of ONUs using their associated downstream data channels, each having at least one time slot, based on the information included in the first control channel.

Abstract: A bi-directional metro-access optical network includes a central office for generating beams of different wavelength bands and a plurality of wavelength locked downward optical signals and for detecting wavelength locked upward optical signals; a plurality of nodes for detecting the downward optical signals of different wavelengths and for generating the wavelength locked upward optical signals of which wavelengths are locked by respective wavelength beams; a first optical fiber line for linking together each of the nodes with the central office in a ring shape, transmitting the upward optical signals to the central office, and transmitting the downward optical signals and the beams to each of the nodes; and a second optical fiber line for linking together each of the nodes with the central office in a ring shape along the circumference of the first optical fiber line.

Abstract: Disclosed is a bidirectional optical add/drop multiplexer that includes a first filter for reflecting a first optical signal pre-selected among input forward optical signals and transmitting the remaining forward optical signals, a second filter for reflecting a second optical signal pre-selected among input reverse optical signals and transmitting the remaining reverse optical signals, a first optical splitter for combining the first optical signal and the forward optical signals by reflection from the first filter, wherein the reflected second optical signal having passed through the first filter is outputted to a connected second drop terminal and the first optical signal input from a connected first add terminal is outputted to the first filter, and a second optical splitter for adding the second optical signal and the reverse optical signals by reflection from the second filter, wherein the reflected first optical signal having passed through the second filter is outputted to a connected first drop termi

Abstract: A wavelength division multiplexed optical access network including a central office for multiplexing first optical signals used for transmitting a high-speed wire data service to a subscriber side and second optical signals used for transmitting a wireless data service to a remote subscriber terminal, a remote node connected to the central office through an optical fiber and for de-multiplexing a multiplexed optical signal received from the central office, a plurality of subscribers connected to the remote node, each subscriber receiving a first optical signal having a corresponding wavelength from among the de-multiplexed first optical signals, and a plurality of radio access units connected to the remote node, each radio access unit converting a second optical signal having a corresponding wavelength from among the de-multiplexed second optical signals into a wireless electric signal and wirelessly transmitting the wireless electric signal.

Abstract: An optical access network of wavelength division method and passive optical network using the same are disclosed. The wavelength division multiplexed optical access network includes a central office for multiplexing first optical signals for wire communication and second optical signals for wireless communication and a remote node connected to the central office through an optical fiber and for demultiplexing a multiplexed optical signal received from the central office. A plurality of subscribers may be connected to the remote node. Each subscriber receives a first optical signal having a corresponding wavelength from among the demultiplexed first optical signals. The network also includes a plurality of radio relay stations connected to the remote node, each radio relay station converting a second optical signal having a corresponding wavelength from among the demultiplexed second optical signals into a radio electric signal and wirelessly transmitting the radio electric signal.

Abstract: A passive optical network using downstream and upstream optical signals for achieving a two-way communication is provided, wherein the downstream and upstream optical signals have different polarization components and an equal wavelength band.

Abstract: The present invention relates to Wavelength Division Multiplexing (WDM) based optical communications, and more particularly to an Fabry-Perot (FP) laser apparatus mode-locked to a multi-frequency lasing light source and an optical transmission apparatus using the same.