Abstract: A time and wavelength division multiplexed passive optical network where a central office has a downstream transmitter and an upstream receiver. The downstream transmitter multiplexes and transmits downstream optical signals in a time region. The upstream receiver de-multiplexes, in a wavelength region, an upstream optical signal. An optical network unit has a downstream receiver and an upstream transmitter, where the downstream receiver de-multiplexes, in the time region, the downstream optical signals from the central office. The upstream transmitter multiplexes the upstream optical signal in the wavelength region and transmits the signal to the central office. A remote node, having an optical distributor and a wavelength division multiplexer, is connected between the central office and the optical network unit. The optical distributor distributes the downstream optical signals from the central office.

Abstract: Disclosed is a wavelength-division-multiplexed (WDM) passive optical network which comprises an optical network unit (ONU) for receiving and transmitting an optical communication service; a remote node having an amplifier for amplifying wavelength of light as being transmitted from the optical network unit; and a central office for receiving the amplified light. In accordance with the WDM passive optical network described herein, it is possible to enhance the quality of the optical communication service provided by the optical network.

Abstract: A wavelength converter for generating a wavelength tunable laser optical source in itself is disclosed. The wavelength converter includes a first semiconductor optical amplifier for generating an optical noise, generating and outputting a first optical source by amplifying the generated optical noise if an external current is applied, first and second distributed Bragg reflectors for reflecting only a component of a specified wavelength range among components of the optical noise and applying the reflected component to the first semiconductor optical amplifier, and a second semiconductor optical amplifier for receiving an optical source divided from the optical source reflected by and outputted from the first distributed Bragg reflector and an input data optical source, generating and outputting a second optical source by changing a phase of the divided optical source according to a digital signal from the input data optical source.

Abstract: An optical signal switching network having a transmitter and a receiver, wherein the transmitter includes a data generator for generating a data signal and a clock signal having the same frequency as the data signal; a clock attenuator for attenuating a frequency of clock signal generated in the data generator at a predetermined ratio; a signal synthesizer for synthesizing the data signal and the attenuated clock signal; a laser generator for generating a laser beam used to transmit the synthesized data signal and clock signal; and a modulator for coupling the synthesized data signal and clock signal to the laser beam and modulating the coupled signal, thereby providing the modulated optical signal to be transmitted to the receiver over an optical fiber

Abstract: A method for enhancing transmission efficiency of burst data by estimating a void between burst data and filling the void with new burst data in an optical burst switching (OBS) network. To this end, a node in the OBS network receives burst data (BD) aggregated from data packets, and a burst control packet (BCP) that is received prior to the BD by an offset time. The BCP contains information relating to the offset time and the BD. To predict the void between the BDs, a void filling time is defined within the offset time using the BCP. The present invention provides the method for determining whether to fill the void and filling the void by directly monitoring the BD over a preset time.

Abstract: A wavelength converter for generating a wavelength tunable laser optical source in itself is disclosed. The wavelength converter includes a first semiconductor optical amplifier for generating an optical noise, generating and outputting a first optical source by amplifying the generated optical noise if an external current is applied, first and second distributed Bragg reflectors for reflecting only a component of a specified wavelength range among components of the optical noise and applying the reflected component to the first semiconductor optical amplifier, and a second semiconductor optical amplifier for receiving an optical source divided from the optical source reflected by and outputted from the first distributed Bragg reflector and an input data optical source, generating and outputting a second optical source by changing a phase of the divided optical source according to a digital signal from the input data optical source.

Abstract: An apparatus for transforming a polarization and a method thereof are provided. The apparatus includes a polarization rotator for rotating a polarization plane of an input optical signal by a specified rotating angle, a polarization beam splitter for dividing the polarization of the optical signal output from the polarization rotator into first and second polarization components, a first monitoring unit for monitoring the first polarization component, a second monitoring unit for monitoring the second polarization component, and a controller for controlling a rotating angle of the polarization rotator so that strengths of the optical signals output from the first and second monitoring unit become equal to each other. Accordingly, a desired polarization component having a constant strength can be obtained by controlling only the rotating angle of the polarization rotator.

Abstract: An apparatus and method for effectively transmitting a packet data and a control data of path information about the packet data in an optical packet data switching network. The method includes grouping a plurality of wavelengths into at least two wavelength bandwidths, each wavelength bandwidth being composed of neighboring wavelengths, and transmitting the optical packet data and the control data with wavelengths of different wavelength bandwidths respectively. Since the wavelength to transmit the optical packet data and the wavelength to transmit the control data has a difference from each other, a node receiving optical data easily divides the packet data and the control data.

Abstract: Disclosed is an optical packet communication system using a wavelength-offset polarization-division multiplexing labeling. An optical signal transmitter which is provided at an ingress node positioned at a sending end in an optical packet switching network, generates and combines packet data and a label, and transmits the combined packet data and label to a core node, wherein the packet data and label have polarization directions perpendicular to each other and maintain a predetermined wavelength interval. A label swapping device detects the label from the combined packet data and label received from the optical signal transmitter, detects next moving position information of the packet data, for generating a new label, substitutes the detected label by the new label, combines the new label with the packet data, and transmits the combined packet data and new label to a next moving position.

Abstract: Apparatuses and methods are provided which suppress a surge component occurring at an optical amplifier on an optical path through which an optical burst signal is transmitted. An optical amplifier may experience a surge due to the power variation of the optical burst signal that is fed to the optical amplifier. To suppress such a surge component, a power corresponding to a number of wavelengths of an optical burst signal to be input is calculated. The optical amplifier is instructed to generate an optical signal with a power corresponding to a difference between a set value and the calculated power. The generated optical signal and the optical burst signal to be input are coupled and output according to the instruction. Thus, the optical amplifier can receive the optical signal with the constant power and the surge component at the optical amplifier can be suppressed.

Abstract: The present invention is directed to an optical router device that is configured to route optical packets in a TDM/WDM optical network. The optical device is disposed in a node of the WDM optical network. The WDM optical network is configured to accommodate a plurality of wavelength channels. Each of the plurality of wavelength channels is configured to propagate optical packets in a time division multiplexed (TDM) arrangement. Each optical packet includes a baseband-payload and a subcarrier modulated (SCM) header. The device includes an optical WDM demultiplexer configured to demultiplex the plurality of wavelength channels. A header recovery component is coupled to the optical WDM demultiplexer. The header recovery element is configured to recover the SCM header in each optical packet propagating on each demultiplexed wavelength channel. A routing control processor (RCP) is coupled to the header recovery component.

Abstract: An optical communication system that includes an optical network is disclosed having a plurality of nodes and a plurality of optical fiber links which includes optical fiber links that interconnect the nodes. Signals passing through the network are similarly pre-compensated and/or similarly post-compensated. The network preferably includes dispersion-managed optical fiber spans, and preferably further includes distributed amplification, preferably erbium amplifiers and/or Raman amplifiers. Preferably, the network is transparent.

Abstract: A method and a system are disclosed for reducing four-wave mixing (FWM) penalties in an optical transmission network. The FWM penalties are reduced by simultaneously and periodically modulating the phase of the optical signals propagating through a long fiber waveguide at a modulation frequency that causes destructive interference of the FWM products that are otherwise generated along the length of the long fiber waveguide. The method may be implemented in an optical transmitter for an optical transmission network by providing a phase modulator between the multiplexer and an optical boost amplifier so as to simultaneously modulate the phase of all the optical signals that are transmitted through the long fiber waveguide. Alternatively, a phase modulator may be disposed between each source of modulated optical signals and the multiplexer so as to separately modulate the phase of all the optical signals that are subsequently transmitted through the long fiber waveguide.

Abstract: The present invention is directed to a protection switch disposed at a node in a two-fiber optical channel protection ring. The protection switch includes a wavelength selective switch (WSS) coupled to the two-fiber optical channel protection ring. The WSS is configured to selectively drop at least one wavelength channel propagating in the two-fiber optical channel protection ring. A dynamic spectral equalizer (DSE) is coupled to the two-fiber optical channel protection ring. The DSE is configured to substantially block wavelengths corresponding to the at least one wavelength channel, and to optically manage at least one express wavelength channel not corresponding to the at least one wavelength channel.

Abstract: A DPSK communication system employs an optical signal which comprises plural, coherent, optical frequencies, each optical frequency positioned within a range of frequencies (i.e., a "frequency slot"). The optical signal comprises plural frequency slots, with the wavefront in each time segment of each frequency slot being phase modulated in accordance with data signals. Plural frequency slots are transmitted "in parallel", in each of a plurality of succeeding time segments. A demodulator includes first and second optical paths, the first component of the optical signal directed onto the first optical path and a second component directed onto the second optical path. A modulator is positioned in at least one of the optical paths and is responsive, during a time segment, to a first applied control signal, to alter the phase, and thus the frequency, of the first component by approximately one frequency slot.