Abstract: A method, a controller, and an optical section include performing an analysis to determine an amount of power offset on any in-service channels in an optical section due to a capacity change with a channel; defining a step size to ensure the capacity change does not exceed an offset limit based on the analysis; performing the capacity change in one or more iterations using the step size to limit the capacity change; and performing an optimization between each of the one or more iterations to adjust amplifier gains in the optical section to compensate for offsets on the in-service channels caused by a previous iteration.

Abstract: System and methods for inferring network topology are described, including a method comprising determining a normalized transmit power of a first device, identifying a second device based upon a parameter of the second device and the normalized transmit power of the first device, and generating a topology including the first device and the second device based upon at least one of the normalized transmit power of the first device and the parameter of the second device.

Abstract: A local oscillation light source outputs locally-oscillated light. An light receiving unit phase-separates an input optical signal by making the optical signal interfere with the locally-oscillated light and outputs an analog electric signal corresponding to the phase-separated optical signal. An analog-to-digital converting unit converts the analog electric signal into a digital signal. A processing unit performs digital signal processing by using the digital signal. A failure detection unit determines whether or not the optical signal is being input to the light receiving unit, or detects a failure in the light receiving unit, the analog-to-digital converting unit or the processing unit based on light intensity of the optical signal, whether or not the analog electric signal can be generated in the light receiving unit, and an amplitude of the analog electric signal output from the light receiving unit.

Abstract: The present invention discloses an optical power monitoring method and apparatus.

Abstract: A method for receiving optical signals and a device using the same method are provided herein. The method includes the elements of receiving an input signal which includes a signal component and an interference component, wherein the interference component is subcarrier to subcarrier intermixing interference (SSII). The input signal is first converted into a frequency domain signal. The interference component of the input signal is estimated based on a mathematical model according to at least a dynamic chirp component and a static chirp component. The interference component is then cancelled from the input signal to obtain an output signal.

Abstract: Example embodiments of the present invention relate to An optical node comprising of at least two optical degrees; a plurality of directionless add/drop ports; and at least one wavelength equalizing array, wherein the at least one wavelength equalizing array is used to both select wavelengths for each degree, and to perform directionless steering for the add/drop ports.

Abstract: The invention discloses a system, a method and an apparatus for optical network protection. The system includes: an output control apparatus for obtaining protection mode information configured by a system and controlling an input signal to be output from a set line corresponding to said protection mode information; and a detection control apparatus for detecting powers of signals transmitted on an active line and on a standby line, if it is determined that the active line is abnormal and the standby line is normal according to detection results, then controlling the input signal to be output from a protection line corresponding to the protection mode information; if it is determined that the active line is normal, or that the active line and the standby line are abnormal according to the detection result, then controlling the input signal to be output from a set line corresponding to the protection mode information.

Abstract: Embodiments provide a methodology for designing a large-scale non-blocking OCS using a multi-stage folded CLOS switch architecture for use in datacenter networks and fiber-rich backbone network POPs. One aspect employs a folded CLOS architecture because of its ease of implementation, enabling the topology to scale arbitrarily with increasing number of stages. The fraction of ports allocated for internal switch wiring (overhead) also increases with the number of stages. Design decisions are made to carefully optimize the insertion loss per module, number of ports per module, number of stages and the total scale required. Other embodiments include folded CLOS switch architectures having at least two stages. In one example, power monitoring may be included only on the leaf switches.

Abstract: An Ethernet-based transmission system using a dying gasp according to the present invention includes an SMPS for supplying power to an Ethernet-based lower level system, detecting a state of a power fault, and outputting a dying gasp alarm signal. A CPU receives the dying gasp alarm signal, and generates and transmits an alarm packet. A PHY chip receives the alarm packet, and uplinks the alarm packet so that the alarm packet is transferred to a higher level stage. An L3 switch receives the alarm packet and determines whether a power fault has occurred in the lower level system. Accordingly, the present invention applies a dying gasp to an Ethernet-based or EPON-based transmission system and is then capable of generating and transmitting an alarm packet so that when a power fault occurs, a device in a higher level network can rapidly determine the occurrence of the power fault.

Abstract: A system, a device, and a method include a network interface device that measures optical power of a passive optical device; generates optical power data, and stores the optical power data. The system, the device, and the method, also includes generating alarms based on the optical power data and communication with remote network interface devices via the passive optical device.

Abstract: An optical transmission device including a wavelength selective switch including plural output ports, an optical intensity monitoring device that receives each optical signal output from the plural output ports of the wavelength selective switch and monitors the optical intensity of the optical signals, and a controller that controls optical intensity of the optical signals from the plural output ports of the wavelength selective switch based on the optical intensities monitored by the optical intensity monitoring device.

Abstract: For testing an optical network, a transmission module transmits a first optical power level on a first optical port of an optical assembly. The optical assembly includes the first optical port, one or more of an optical cable and an optical waveguide, and a second optical port. The optical assembly is installed in an assembled computer in a state suitable for an end user. A measurement module measures a second optical power level on the second optical port, and a determination module determines a quality level by determining if the second optical power level is below a quality threshold value. The transmission module, the measurement module, and the determination module function within an assembled computer in a state suitable for an end user.

Abstract: In one embodiment, a local network device collects local optical power information for at least one of either a local optical transmit interface and a local optical receive interface of the local network device. The local network device may then exchange the local information for remote optical power information of corresponding remote optical receive and transmit interfaces of a remote network device at an opposing end of at least one corresponding optical link (fiber). For example, an exchange may use a point-to-point protocol which may dynamically determine/discover neighboring relationships between capable peer device interfaces and establish a suitable communication exchange between the capable peers. Based on the local information and exchanged remote information, the local network device may calculate an optical power loss of each corresponding optical link.

Abstract: An ONU includes a power-interruption detecting unit configured to detect power interruption of the ONU, a transmitting and receiving unit capable of being set in a power saving state, and a PON-side control unit configured to notify an OLT of, as power saving return information, a power holding time during occurrence of the power interruption of the ONU and a startup time, which is time until the transmitting and receiving unit returns from the power saving state, and, when the power-interruption detecting unit detects the power interruption, transmit a power interruption notification to the OLT. The OLT includes the PON control unit configured to determine, based on the power saving return information, whether the ONU can transmit the power interruption notification when the power interruption occurs in the power saving state.

Abstract: Described herein is an optical channel monitor (1) including a protective housing (3), an input port (5) disposed in the housing (3) and configured for receiving at least one input optical signal (7) including one or more optical channels separated by wavelength. A wavelength configurable laser (9) is located within the housing (3) and is configured to provide an optical reference signal (11) at a first wavelength (?r). The laser (9) is adapted to scan across a range of wavelengths covering the one or more optical channels. An optical mixing module (13) is coupled to the input port (5) and the laser (9) for mixing the input optical signal (7) with the optical reference signal (11) to produce a mixed output signal. A receiver module (15) is configured to receive the mixed output signal and extract signal information indicative of at least the optical power of the at least one input optical signal at the first wavelength (?r).

Abstract: A method of processing optical signal (TE) whose power (PE) varies in a random manner in a range of variation of power (?PE) around a mean power (PE?), the processing of the optical signal (TE) generating processing noise (GELECTRONIC), characterized in that the relative variation of power (GE) of at least a temporal part at said optical signal (TE) is optically amplified.

Abstract: The present invention provides a signal detection method, including: receiving, by a frequency mixer, wavelength division multiplexing signals and a local oscillator signal, where a wavelength of the local oscillator signal and a wavelength of a target signal in the wavelength division multiplexing signals are the same; a frequency mixer performs interference on the wavelength division multiplexing signals through the local oscillator signal to obtain a coherent signal formed by the local oscillator signal and the target signal; sending the coherent signal to a transimpedance amplifier for amplification to obtain a voltage signal; and obtaining the power of the target signal according to a power amplitude of the voltage signal.

Abstract: A method and device for visible light communication is disclosed. The method comprises selecting a first sequence and a second sequence of light intensity frequencies to represent a first symbol and a second symbol, respectively, for embedding data. The method comprises further transmitting a light signal. The light signal comprises time periods in which a light intensity of the light signal is sequentially controlled according to the selected sequence of light intensity frequencies. Thereby, a frequency hopping light signal is generated, in which data may be embedded. The light signal may be generated and transmitted by the device comprising a light emitter.

Abstract: Systems and method for monitoring an optical power of a dual-polarization signal are disclosed. The systems and methods may include measuring a first parameter set associated with a supervisory signal, the supervisory signal being communicated in-band with the dual-polarization signal; calculating a second parameter set from the first parameter set; calculating an intensity value from the second parameter set, the intensity value associated with one of the polarization states of the dual-polarization signal; and estimating a signal power associated with the supervisory signal from the intensity value.

Abstract: The embodiments provide an automatic bias control method and apparatus for an optical transmitter. The apparatus includes: a detecting unit configured to monitor output optical power of an I/Q modulator of the optical transmitter; a calculating unit configured to calculate bias voltage indicating values of the I modulator, Q modulator and phase modulator of the I/Q modulator according to the output optical power and known modulation data; and an adjusting unit configured to adjust respectively Direct-Current (DC) bias voltages of the I modulator, Q modulator and phase modulator according to the bias voltage indicating values of the I modulator, Q modulator and phase modulator. With the embodiments, known modulation data are used to realize automatic bias control by monitoring the evenness of distribution of the power of output optical signals of the transmitter in the four quadrants of an I/Q plane.

Abstract: A method and system for transient and switching stabilization of a fiber optic transport system. One or more data-bearing channels are coupled to an optical fiber. The data-bearing channels are distributed among a plurality of frequency sub-bands. A set of control channels is also coupled to the optical fiber. Each control channel includes a pair of signals at separate frequencies. There is at least one control channel in each of the plurality of frequency sub-bands. The pair of signals of a control channel are cross-polarized. Optical power in at least one of the plurality of sub-bands is measured. Responsive to the measured optical power, the optical power of a control channel is adjusted to maintain a substantially constant power of a sub-band that contains the adjusted control channel.

Abstract: An optical transmission device includes a first power monitor to monitor a first signal into which second signals with respectively different wavelengths are multiplexed so as to measure received power of the first signal; an amplifier to amplify the first signal, to generate a third signal; a driver to drive the amplifier; a demultiplexer to separate the third signal into fourth signals with the different respectively wavelengths; second power monitors each to monitor each of the fourth signals so as to measure received power of each of the fourth signals; a memory to store therein data related to gain in the amplifier, the data corresponding to each of wavelengths of the second signals, with respect to parameters which are the received power measured by the first power monitor and driving condition; and a processor to calculate power of each of the second signals.

Abstract: An optical communication system comprises a network interface device (NID) having a media converter coupled to an optical fiber of a passive optical network (PON). The media converter converts optical signals from the PON into electrical signals for communication across at least one non-optical channel, such as a conductive or wireless connection, to customer premises equipment (CPE), such as a residential gateway or other customer premises (CP) device. Rather than implementing an optical media access control (optical MAC) layer in the NID, an optical MAC layer for handling PON protocols and management is implemented by the CPE, thereby effectively extending the customer end of the PON across at least one non-optical connection to the CPE. By implementing the optical MAC layer at the CPE, the complexity of the NID is reduced thereby lowering the cost of the NID.

Abstract: An optical power monitor that detects optical power of respective wavelengths of a signal light in a wavelength multiplexing system, includes: a light emitter configured to superimpose a frequency modulation component on a signal light; a wavelength tunable filter configured to sweep a pass band of the signal light across a wavelength band for a signal light; and a detector configured to detect intensity changes in optical power passing through the wavelength tunable filter with a frequency modulation of the optical power, and to detect an optical power measurement value at a middle point of two points of the intensity changes of the optical power as the optical power of a wavelength to be measured.

Abstract: A frequency modulation signal demodulator includes: an optical signal that has a wavelength, a frequency modulation signal being superimposed onto the optical signal; an optical filter that inputs the optical signal and has a central wavelength of a pass band at a wavelength that is shifted from a central wavelength of a spectrum of the optical signal and that is set to allow the pass band to be located at one portion of the spectrum; and an asymmetry optical interferometer that demodulates the frequency modulation signal by splitting light which has passed through the optical filter, delaying different time between split lights, and interfering the split lights.

Abstract: A network monitoring system for a multimode optical data network includes a filter based splitter and an avalanche photodiode detector-based detection subsystem. The system takes a very small amount of the energy from the main data stream to use as monitoring data signal. The filter based splitter operates in a manner that is fairly uniform among modes and permits very low energy levels to be diverted for monitoring without disrupting either the main or monitor data streams for any modes.

Abstract: An optical transmission system includes a first node and a second node, the first node includes a first optical amplifier which outputs a signal to the second node through a first transmission line and a first monitoring unit, the second node includes a monitor which monitors a signal from the first transmission line, a second optical amplifier which outputs a signal to the first node through a second transmission line and a second monitoring unit, upon detecting disconnection from the first transmission line, the second monitoring unit transmits a notification for making power of the first optical amplifier reduced, upon receipt of the notification, the first monitoring unit reduces power of the first optical amplifier, and transmits a completion notification to the second monitoring unit, and upon not receiving the completion notification even after expiration of an allowed time, the second monitoring unit reduces power of the second optical amplifier.

Abstract: Systems and methods according to these exemplary embodiments provide for methods and systems that allow for either reducing signal loss or improving the optical signal strength in a PON for increasing optical signal range.

Abstract: An apparatus for monitoring optical equipment in an optical circuit is disclosed in which the apparatus may include an optical device situated to receive an optical input signal and to reflect a portion of the energy of the received optical input signal, thereby providing a reflected input signal; a first photodiode located along a path of the reflected input signal, and operable to receive optical energy from the reflected optical input signal and from ambient optical power; a second photodiode located substantially outside the reflection path of the optical input signal; and means for calculating a magnitude of a power level of the optical input signal from values of outputs from the first and second photodiodes.

Abstract: There is provided an optical receiver including a variable-ratio splitter to split an input signal light into a plurality of signal lights, based on a variable ratio, a plurality of photo detectors to receive the plurality of signal lights respectively, an operation circuit to output a reception electrical signal, based on a reception processing on one of the plurality of signal lights, a calculation circuit to calculate a total power of the plurality of signal lights received by the plurality of photo detectors, and an output unit to output a signal regarding the total power.

Abstract: The path selection and wavelength assignment to a selected path are performed by mapping the wavelength reach to the demand distribution (agile reach) resulting in a 50-60% increase in the network reach. The network reach is further increased (about 2.2 times) when on-line measured performance data are used for path selection and wavelength assignment. The connections may be engineered/upgraded individually, by optimizing the parameters of the entire path or of a regenerator section of the respective path. The upgrades include changing the wavelength, adjusting the parameters of the regenerator section, controlling the launch powers, mapping a certain transmitter and/or receiver to the respective wavelength, selecting the wavelengths on a certain link so as to reduce cross-talk, increasing wavelength spacing, etc.

Abstract: A system, method and apparatus for power saving using burst-mode transmission over point-to-point physical connections. In one embodiment, a physical layer device (PHY) is provided that includes a data detector that is configured to generate a first control signal upon receipt of a non-idle code group over an interface between the PHY and a media access control (MAC) device and to generate a second control signal when all data received from the MAC device has been transmitted by the physical layer device. The PHY also includes a laser for transmission of data over an optical network cable, the laser being configured to perform a first transition from an off state to an on state based on the first control signal, and to perform a second transition from the on state back to the off state based on the second control signal.

Abstract: A system includes two optical modules that perform auto-setting of the optical links between the optical modules. One optical module sends an optical signal with a test pattern to the other optical module. If the receiving module determines that the test pattern is successfully received, it sends a pass indication to the transmitting module, and the transmitting module can configure its driver path in accordance with a transmit current setting used to transmit the test pattern. If the test pattern is not successfully received, the receiving module sends a fail indication, and the transmitting module can increase the transmit current setting and resend the test pattern. When the system includes multiple optical channels, one channel can be tested while feedback is provided on another channel. The system can iterate through all optical channels until they are all configured.

Abstract: An apparatus and method for managing a dynamic bandwidth allocation to support a low-power mode, in a passive optical network (PON) are provided. The apparatus may include a power saving mode managing unit to manage a power saving mode of at least one optical network unit (ONU), a bandwidth allocation parameter storage unit to store a bandwidth allocation parameter used for a power saving mode, and to maintain the stored bandwidth allocation parameter, and a dynamic bandwidth allocating unit to provide bandwidth allocation information to the at least one ONU, when the stored bandwidth allocation parameter is received.

Abstract: An optical transmission device according to the present invention comprises: a Raman amplification means; a main signal light sending means which sends first main signal light; a communication interruption detection light monitoring means which sends a first signal if it cannot detect communication interruption detection light; a main signal light monitoring means which sends a second signal if it cannot detect second main signal light; a light monitoring signal analysis means which sends a result of its analysis of a light monitoring signal as a third signal in a predetermined period of time; and a control means which makes the Raman amplification means suspend the generation of the excitation light, if it cannot receive the third signal even after the elapse of the predetermined period of time in the state it has received the first signal and has not received the second signal, and stops sending of the first main signal light from the main signal light sending means when receiving the second signal further.

Abstract: An optical communication system connects a plurality of user-side optical line terminating apparatuses (hereinafter referred to as ONUs) to a station-side optical line terminating apparatus (hereinafter referred to as OLT) using a common optical fiber. At least a part of the ONUs includes a transceiver having a power saving function for inactivating a transmitting unit while supplying electric power to a receiving unit and a control apparatus that transmits support information of the power saving function to the OLT via the transceiver, and the OLT includes a control apparatus that generates transmission allowance information of upstream communication based on the support information of the power saving function and a transceiver that receives the support information of the power saving function and transmits the transmission allowance information to the ONU.

Abstract: The object of the present invention is to reliably prevent deterioration and failure of reception relevant parts in a transmission apparatus on a reception side without using an attenuator. An output value control method that controls an output value of output information transmitted from each of transmission apparatuses, in which a transmission apparatus transmits the output information having a minimum output value as the output value to the other transmission apparatus, and when the output information does not reach the other transmission apparatus, the transmission apparatus repeats transmission of the output information after increasing the own output value by adding a predetermined value to a previous output value, and then the other transmission apparatus that has received the output information calculates the output value of the transmission apparatus, and notifies the calculated output value of the transmission apparatus as an appropriate output value to the transmission apparatus.

Abstract: A waveform reconstruction device (140) includes: a phase-spectrum calculation unit (143) which (i) simulates, for each intensity of an input optical signal assumed to have a given phase spectrum, propagation of the input optical signal through an optical transmission medium, to calculate a power spectrum of an output optical signal, and (ii) performs iterations of simulating the propagation while changing the given phase spectrum to reduce differences between calculated power spectra and measured power spectra of the input optical signal having the intensities, to search for a phase spectrum of the input optical signal; and a waveform reconstruction unit (144) which reconstructs a time waveform of the input optical signal using the phase spectrum found through the search, wherein the phase-spectrum calculation unit (143) changes the given phase spectrum or simulates the propagation, based on a nonlinear optical effect or a dispersion effect.

Abstract: An apparatus for measuring performance of a coherent optical receiver includes a beam splitter splitting light into first and second paths, a first optical modulator modulating the first path light, a variable optical attenuator controlling an optical power of the first optical modulator, a first polarization controller transmitting a signal controlling polarization of an output of the variable optical attenuator to the coherent optical receiver, a second optical modulator modulating the second path light, a variable optical delay line delaying time of an output of the second optical modulator, a second polarization controller transmitting a signal controlling polarization of an output of the variable optical delay line to the coherent optical receiver, a network analyzer measuring performance of the coherent optical receiver and controlling the optical modulators, and a controller transmitting a control signal to the optical modulators.

Abstract: An optical line terminal which includes an observing unit that observes information of any one or all of an arrival interval of frames, an instantaneous bandwidth under use of a flow, a queue length of a queue temporarily storing the frames, and a traffic type, and a stop determining unit that dynamically determines a sleep time to be a period in which a sleep state where partial functions of the ONU are stopped is maintained, on the basis of the information obtained by the observing unit. The ONU is entered into a sleep state, immediately after communication ends, after a predetermined waiting time passes from when the communication ends, or after a waiting time determined on the basis of the information passes from when the communication ends.

Abstract: Methods and systems for mitigating degradation of an optical signal-to-noise ratio (OSNR) induced by polarization dependent loss (PDL) in an optical network include determining an increase in power (?P) corresponding to a PDL-induced decrease in OSNR for a given channel being transmitted over an optical signal transmission path. The increase in power (?P) may be adjusted for at least some of the network nodes in the optical signal transmission path. At certain network nodes, the increase in power (?P) may be realized with a combination of attenuation and gain.

Abstract: Described herein is an optical channel monitor (1) including one or more input optical ports (3) for receiving an input optical signal (5) including a plurality of optical channels. A first monitoring module (7) is configured to selectively scan a predetermined spectral region of the optical signal including at least one optical channel for low resolution monitoring. A second monitoring module (11) is configured to simultaneously scan a subregion within the predetermined spectral region for high resolution monitoring.

Abstract: Systems and method for monitoring an optical power of a dual-polarization signal are disclosed. The systems and methods may include measuring a first parameter set associated with a supervisory signal, the supervisory signal being communicated in-band with the dual-polarization signal; calculating a second parameter set from the first parameter set; calculating an intensity value from the second parameter set, the intensity value associated with one of the polarization states of the dual-polarization signal; and estimating a signal power associated with the supervisory signal from the intensity value.

Abstract: In a first aspect, the method and apparatus of the present disclosure can be used to periodically and/or intermittently place one or more ONUs attached to a PON in a power savings mode so that an OTDR test can be performed. While in the power savings mode, the ONUs temporarily suspend their transmitter function and power down their upstream lasers. In a second aspect, the method and apparatus of the present disclosure can be used to coordinate the performance of OTDR during one or more periodic or intermittent discovery slots used to detect and register ONUs recently connected to the PON. Because new ONUs are infrequently connected to the PON and ONUs already registered are not permitted to transmit during the discovery windows, OTDR can be performed during these windows without impacting, to a great degree, the normal operation of the PON.

Abstract: An optical module for receiving light according to a digital coherent optical transmission scheme includes two optical fibers, and a monitor PD. The optical signal processing circuit includes a substrate, an optical waveguide layer made up of a core and a clad layer stacked on top of the substrate, and fixtures stacked on top of the clad layer on the one end, and is provided with a light shield member which spans the substrate, the clad layer, and the edge face of the fixture on the edge face of the optical signal processing circuit that faces the monitor PD, and which includes an aperture unit aligned with the given site where the diverted signal light is output.

Abstract: A portable apparatus for measuring parameters of optical signals propagating concurrently in opposite directions in an optical transmission path between two elements, at least one of the elements being operative to transmit a first optical signal (S1) only if it continues to receive a second optical signal (S2) from the other of said elements, comprises first and second connector means for connecting the apparatus into the optical transmission path in series therewith, and propagating and measuring means connected between the first and second connector means for propagating at least the second optical signal (S2) towards the one of the elements, and measuring the parameters of the concurrently propagating optical signals (S1, S2). The measurement results may be displayed by a suitable display unit. Where one element transmits signals at two different wavelengths, the apparatus may separate parts of the corresponding optical signal portion according to wavelength and process them separately.

Abstract: An example embodiment involves a method for adjusting an operating parameter of a node in an optical network which comprises a plurality of nodes, the method comprising the steps of: measuring at the node a value of at least one characteristic associated with the operating parameter of the node; distributing the value of the characteristic to all of the other nodes in the network; receiving at the node the value of the characteristic for all of the other nodes in the network; deriving at the node optical impairment data for each link of the network based on the received values of the characteristic for all of the nodes; calculating at the node the preferred value of the operating parameter for each node based on the derived optical impairment data; and adjusting the operating parameter of the node based on the calculated preferred value for the node.

Abstract: An optical transmission device includes a splitter configured to have at least a first port, a second port, and a third port that output branched input light, branching ratios of the first port and the second port being variable, and a controller configured to reduce an optical level of output light from the first port to be monitored and increase an optical level of output light from the second port according to the reduced optical level of output light from the first port by controlling the branching ratios.

Abstract: An optical transceiver and/or optical network, and methods of monitoring optical transceivers, may be useful for increasing the dynamic range and/or determining the received signal strength and/or link budget of the optical transceiver and/or a different optical transceiver in the optical network. The circuitry generally comprises a photodiode configured to generate a first current responsive to an optical signal, a current mirror configured to produce a second current equal or proportional to the first current, and a nonlinear element configured to produce a first voltage from the first current.

Abstract: Systems and methods according to these exemplary embodiments provide for methods and systems that allow for either reducing signal loss or improving the optical signal strength in a PON for increasing optical signal range.