Abstract: Apparatus and method for equalizing a multiplicity of amplifier optical output signals comprised of a combined broadcast optical signal and a narrowcast optical signal having different bands of wavelengths of light by adjusting the power output level of at least one the signals in response to an amplified sample of the signal. A light switch or attenuator and a sensor for determining whether a transmission fiber is in place is connected to each of the multiplicity of optical output signals to allow the optical output signals to be turned on and off for maintenance and repair.

Abstract: In one embodiment, a method of passively adding traffic from a first optical network to a second optical network includes receiving ingress traffic from an optical ring of the first network at a node coupled to the first network, generating a first and second copy of the traffic, passively forwarding the first and second copies of the traffic, splitting the second copy of the traffic into multiple substantially identical copies, and filtering at least one of the copies of the second copy of the traffic into one or more constituent wavelengths. The method further includes selectively forwarding the signal in one or more constituent wavelengths of the second copy of the traffic to a node coupled to the second network, receiving the forwarded signal in one or more wavelengths at the node, and adding the forwarded signal in one or more wavelengths to an optical ring of the second network.

Abstract: An optical multilevel-coded signal transmission system transmits information from an optical transmitter to an optical receiver through an optical transmission line using optical intensity and optical phase separately. The optical transmitter includes an inverted RZ signal light generator to generate an inverted RZ signal light intensity-modulated with a first data, and an optical phase modulator to phase-modulate the inverted RZ signal light according to a second data. The optical receiver includes a splitter to split a light input from the optical transmission line into first and second portions, an inverter to invert the first portion from the splitter, a first detector to detect the first data in the first portion inverted by the inverter, a converter to convert a phase-modulated signal included in the second portion from the splitter into an optical intensity-modulated signal, and a second detector to detect the second data in the optical intensity-modulated signal from the converter.

Abstract: An optical data processing network having an optical network interface is disclosed. The optical data processing network includes a first multi-processor system and a second multi-processor system. The first multi-processor system includes a first set of processors and a first set of optical network interfaces electrically coupled to the first set of processors. Similarly, the second multi-processor system includes a second set of processors and a second set of optical network interfaces electrically coupled to the second set of processors. An optical cable is connected between the first set and the second set of optical network interfaces. The first multi-processor system communicates with the second multi-processor system via the optical cable.

Abstract: Provided is a WDM-PON system based on a wavelength-tunable ECL. A method of controlling an upstream optical wavelength of an ONT in WDM-PON system, the method comprises: determining upstream optical wavelength information of the ONT corresponding to a downstream optical wavelength predetermined to the ONT newly installed by being connected to a network; in an OLT, loading the determined upstream optical wavelength information onto the downstream optical wavelength assigned to the ONT and transmitting the loaded upstream optical wavelength information to the ONT; in the ONT, generating an upstream optical wavelength based on the upstream optical wavelength information transmitted by being loaded on the downstream optical wavelength from the OLT; and in the ONT, loading upstream data onto the generated upstream optical wavelength and transmitting the loaded upstream data to the OLT.

Abstract: An optical communications system has a transmitter which uses modulation using multiple level phase and/or amplitude modulation, and is adaptable to provide modulation for different signals using different selections of the multiple levels. A receiver is able to perform demodulation from the multiple level phase and/or amplitude modulation, and is adaptable to provide demodulation of signals modulated using the different selections of the multiple levels. This provides an adaptive modulation system, so that different bit rates can be employed for different links.

Abstract: Provided are an optical transponder that processes a G.709 frame that includes an overhead for operation, administration, and maintenance of an optical channel and an overhead for forward error correction, and a method of detecting and treating errors in optical-channel sublayers of the same. The method includes detecting an error signal or a maintenance signal from a G.709 frame that includes an overhead for operation, administration, and maintenance of an optical channel and an overhead for forward error correction; treating errors in a predetermined layer of a plurality of layers that requires error treatment when the error signal or the maintenance signal is detected or canceled; and investigating a reason for the errors in the predetermined layer.

Abstract: A method and system of coherent detection of optical signals. The system utilizes a digital signal processor to recover an incoming optical signal. The system employs a local oscillator, which does not need to be phase locked to the signal. The signal may be consistently recovered, even when the polarization state varies over time. Additionally, the signal may be recovered when it comprises two channels of the same wavelength that are polarization multiplexed together. In addition, any impairment to the signal may be reversed or eliminated.

Abstract: Systems and methods use single-fiber optical add/drop multiplexers (OADMs) to enable bi-directional data transmission in WDM systems over a single fiber. By reducing the required capacity for an optical network from dual fibers to a single fiber, significant cost and bandwidth efficiencies are achieved. The systems and methods also provide redundancy protection in single-fiber bidirectional line ring systems. In the event of a downstream fiber or device failure, the OADM module receives a signal on a first wavelength from a first direction, shifts the signal from the first wavelength to a second wavelength, and sends the signal back down the fiber it originated from on the second wavelength, thus maintaining the propagation of the signal in the ring system.

Abstract: An apparatus and system are provided for delivering communication services such as video, data and telephony services to individual residential units. According to one embodiment, an optical network terminal (ONT) for providing communication services to a single residential unit comprises a passive optical network interface (PI) circuit, a residential service interface (RSI) circuit, and a power unit. The PI circuit receives optical signals from an optical fiber and transmits optical signals onto the optical fiber. The PI circuit is adapted to convert received optical signals containing voice information to electrical voice ATM cells, received optical signals containing data information to electrical data ATM cells, and received optical signals containing video signals to electrical video signals. The PI circuit is also adapted to convert electrical voice ATM cells and electrical data ATM cells to optical signals for transmission over the optical fiber.

Abstract: A signal transmitting apparatus for an optical base station is disclosed. According to the invention, a base station outputs a digital IQ signal to an optical connecting unit. The optical connecting unit processes the digital IQ signal digitally, and transmits the digital signal over an optical network to a remotely located optical base station. The remote station digitally processes the signal before converting to an RF signal for transmission. The invention advantageously decreases signal loss and noise associated with analog processing in the optical connecting units and remote stations in the related art. System reliability is also improved.

Abstract: An optical transmitter for generating return-to-zero alternative-mark-inversion (RZ-AMI) optical signals and a method for generating the optical signals are provided. The optical transmitter includes a light source radiating at its output an intensity-modulated light beam based upon intensity of a first data, a precoder for precoding a second data having the information identical to the first data, and a Mach Zehnder modulator for phase-modulating the intensity-modulated light on basis of the precoded second data to generate a return-to-zero alternative-mark-inversion (RZ-AMI) optical signal.

Abstract: Disclosed is a passive optical network comprising a central office including a plurality of first reflective semiconductor optical amplifiers of a quantum-dot type, each of which generates a wavelength-seeded downstream optical signal on a downstream channel of a corresponding wavelength, a plurality of optical network units each of which includes a second reflective semiconductor optical amplifier of a multi-quantum-well type, the second reflective semiconductor optical amplifier generating a wavelength-seeded upstream optical signal on an upstream channel of a corresponding wavelength and a remote node for outputting the downstream optical signals to corresponding optical network units, and multiplexing and outputting the upstream optical signals to the central office.

Abstract: A communication system includes: at least one light-emitting device for emitting a light; and at least one light-receiving device for receiving the light emitted from the at least one light-emitting device. The light-emitting device further includes: at least one driver unit for generating a modified current based on an externally entered information signal; and at least one light-emitting unit operatively and functionally coupled to the at least one driver unit for receiving the modified current and emitting a modified signal light including any information based on the modified current. The at least one light-emitting unit includes at least one electroluminescence element.

Abstract: An optical transmitter system supplies a plurality of different wavelength optical radiation components to a transmission element which, in operation, is connected to the transmitter system for conveying the different wavelength radiation components to a respective receiver. The transmitter system detects a loss of a wavelength radiation component at the respective receiver. The supply of the wavelength component is interrupted in response to a detection of loss of the wavelength component at the receiver. A timing circuit provides respective restart times which differ one to another for the wavelength radiation components. The supply of the wavelength component is restarted, following an interruption, at the restart time provided by the timing circuit.

Abstract: Disclosed is a upstream data transmission method in a gigabit Ethernet-passive optical network (GE-PON) system. In the GE-PON system including an optical line termination having a scheduler and optical network units connected to the optical line termination, the optical line termination receives bandwidth allocation request signals from the optical network units at a start of a first cycle, allocates transmission bandwidths to the respective optical network units in accordance with the bandwidth allocation request signals, and transmits the allocated transmission bandwidths to the respective optical network units before a second cycle that follows the first cycle.

Abstract: Disclosed herein is a system for providing dynamic service using optical sub-carrier multiplexing type multi-channel access and method of controlling the same. The system includes a plurality of optical sub-carrier multiplexing modems, an optical gigabit-Ethernet switch and a plurality of wavelength division multiplexing couplers. The optical sub-carrier multiplexing modems transmit user traffic using multiple optical sub-carrier channel control. The optical gigabit-Ethernet switch is connected to an access network upstream and to the optical sub-carrier multiplexing modems downstream to manage a plurality of wavelengths and a plurality of optical sub-carrier channels according to the wavelengths. The wavelength division multiplexing couplers connect the plurality of optical sub-carrier multiplexing modems with the optical gigabit-Ethernet switch, perform aggregation and branching of a certain wavelength and transmit it.

Abstract: Disclosed herein is an optical node device applicable to an optical network including a closed loop provided by an optical fiber. This optical node device includes a tunable wavelength selecting element adapted to input WDM signal light obtained by wavelength division multiplexing a plurality of optical signals having different wavelengths, the tunable wavelength selecting element having a function of dropping at least one optical signal from the WDM signal light and a function of adding at least one optical signal to at least one unassigned wavelength channel of the WDM signal light; and a wavelength selecting filter optically connected to the tunable wavelength selecting element for removing noise present in any bands other than a signal band of each optical signal passing through the tunable wavelength selecting element.

Abstract: Methods and apparatus are provided for reducing Raman crosstalk in a wavelength-division-multiplexing (WDM) optical fiber transmission system that transmits a multiplex of channels. Idle data is sent over one or more of the channels of the WDM system in order to maintain the optical link when user data is not being sent. The idle data has an idle data pattern, which can be controlled such that a power spectral density of a signal carried by at least one channel is shifted in order to reduce Raman crosstalk between the channels. For example, the power spectral density may be shifted away from lower frequencies of the channel, and toward the higher frequencies, by controlling the idle data pattern. Alternatively, the power spectral density may be shifted towards unused frequencies of the channel, by controlling the idle data pattern.

Abstract: A method for protection switching includes receiving an optical signal from a transponder coupled to a client and optically splitting the signal to a first output and a second output. The first output is coupled by a first optical add-drop multiplexer to a first optical fiber, and the second output is coupled by a second add-drop multiplexer to a second fiber. The method further includes selecting one of the output signals for the working channel, and communicating the selected output signal to an optical network. During communication of the selected output signal to the optical network, the method includes monitoring for a failure condition in the optical network and, if the failure condition is detected, selecting the other output signal as the working channel and communicating the new selected output signal.