Abstract: Control and monitoring of airfield lighting from a control tower and other maintenance/supervisory locations uses double loop self healing fiber optic communications circuits to enhances speed of operation even with large and complex airfield lighting system requirements, and significantly increased reliability and operating lifetime thereof. A plurality of local light control and monitoring groups are used, wherein each group has at least one fiber optic communications concentrator that independently communicates with light controllers within the group and the remote supervisory control and monitoring systems in the control tower and other locations. This allows faster control response of the lamps in each of the airfield light fixtures, and monitoring concentration of operational data within each group.

Abstract: In a communication line switching method for an optical communications system in which a station-side line terminal apparatus and user-side line terminal apparatuses are connected via a plurality of redundant physical lines, the discovery of the station-side optical line terminal registering the user-side line terminal apparatuses, wherein the registered user-side line terminal apparatuses monitoring a time stamp drift error that is generated when a difference between a time stamp included in a received signal and a local time measured by the own apparatus is larger than a value set in advance and, when the time stamp drift error occurs, shifting to a deregistered state and waiting for registration by the discovery. The station-side line terminal apparatus switches a physical line from a working physical line to a backup physical line of the physical lines.

Abstract: A method and apparatus of detecting a rogue optical network unit (ONU) is provided. An optical line terminal (OLT) detects an abnormal upstream transmission to determine a plurality of rogue ONU candidates, and transmits a sleep allow message instructing a transition to a sleep mode to each of the plurality of rogue ONU candidates. The OLT detects the rogue ONU among the plurality of rogue ONU candidates based on upstream transmissions from the plurality of rogue ONU candidates in the sleep mode. Since the detection of the rogue ONU is performed in the sleep mode, the remaining ONUs can transition from the sleep mode to the normal mode after the detection of the rogue ONU is completed, thereby making it possible to rapidly resume upstream communication.

Abstract: The invention refers a method and an arrangement for in service Raman gain measurements and monitoring of a wavelength division multiplex system. By measuring the power level values of a transmitted WDM signal (WMS_TX) and an optical supervisory signal (OSS_TX) at the transmitter and the power level values of the received signals (WMS_RX; OSS_RX) the Raman gain can be calculated for the different channels.

Abstract: A communication device may be operable to determine, in an optical module, a signal quality associated with each of one or more host transmitter filters in a host circuit. The signal quality may be communicated from the optical module to the host circuit via a management interface. The communication device may control, in the host circuit, configuration of each of the host transmitter filters based on the signal quality. The communication device may be operable to determine, in the host circuit, a signal quality associated with each of one or more module transmitter filters in the optical module. The signal quality associated with each of the module transmitter filters may be communicated from the host circuit to the optical module via the management interface. The communication device may control, in the optical module, configuration of each of the module transmitter filters based on the signal quality.

Abstract: A control apparatus for controlling an optical receiver having delay paths comprises an optical variable attenuator configured to generate a variable signal and provide the variable signal to the optical receiver; a fine control voltage controller configured to generate a variable fine control voltage and input the variable fine control voltage to one path of the delay paths of the optical receiver; a photo-diode voltage monitor configured to detect a first voltage value and a second voltage value; a bit error rate (BER) checker configured to estimate a bit error rate (BER) according to a signal output from the optical receiver; and a controller configured to set a value of the variable signal and a value of the variable fine control voltage and to estimate the fine control voltage that makes the bit error rate a minimum according to the first voltage value and the second voltage value.

Abstract: A method for localizing an optical network termination in an optical access network including an optical line termination and a number of optical links.

Abstract: A joint switching method for an aggregation node, an aggregation node, and an optical network protection system including an aggregation node are provided. By monitoring information transferred between an active optical line terminal (OLT) and a broadband network gateway (BNG), the aggregation node finds a fault in time according to the monitored information and when a fault occurs, the aggregation node starts a local protection solution, enables a corresponding backup port connected to a backup OLT corresponding to the active OLT, and disables an active port connected to the active OLT. Through the method, when the active OLT is switched to the backup OLT, the aggregation node performs joint switching, which ensures normal communication.

Abstract: An apparatus comprising an optical transmitter, a coarse tuner coupled to the optical transmitter and having a first tuning range, a fine tuner coupled to the optical transmitter and having a second tuning range smaller than and within the first tuning range, a wavelength division demultiplexer coupled to the optical transmitter and to a plurality of optical fibers, and a detector coupled to the optical transmitter and the wavelength division demultiplexer.

Abstract: In a communication line switching method for an optical communications system in which a station-side line terminal apparatus and user-side line terminal apparatuses are connected via a plurality of redundant physical lines, the discovery of the station-side optical line terminal registering the user-side line terminal apparatuses, wherein the registered user-side line terminal apparatuses monitoring a time stamp drift error that is generated when a difference between a time stamp included in a received signal and a local time measured by the own apparatus is larger than a value set in advance and, when the time stamp drift error occurs, shifting to a deregistered state and waiting for registration by the discovery. The station-side line terminal apparatus switches a physical line from a working physical line to a backup physical line of the physical lines.

Abstract: Terminals of upstream and downstream sides of an in-service line and a detour line are connected by optical couplers. An optical oscilloscope is connected to one optical coupler, and a chirped pulse light source is connected to the other optical coupler to thereby form dualized lines. The detour line includes an optical line length adjuster for compensating for the phase difference of optical transmission signals that occurs because of the optical line length difference with the in-service line. Pulse light in which an optical frequency is chirped is transmitted from the chirped pulse light source. The pulse light is branched by the second optical coupler, passes through the in-service line and the detour line, is multiplexed again by the first optical coupler, and is measured by the optical oscilloscope.

Abstract: An apparatus comprising a path computation element (PCE) configured for at least partial impairment aware routing and wavelength assignment (RWA) and to communicate with a path computation client (PCC) based on a PCE protocol (PCEP) that supports path routing, wavelength assignment (WA), and impairment validation (IV). Also disclosed is a network component comprising at least one processor configured to implement a method comprising establishing a PCEP session with a PCC, receiving path computation information comprising RWA information and constraints from the PCC, establishing impairment aware RWA (IA-RWA) based on the path computation information and a private impairment information for a vendor's equipment, and sending a path and an assigned wavelength based on the IA-RWA to the PCC. Disclosed is a method comprising establishing impairment aware routing and wavelength assignment for a plurality of network elements (NEs) in an optical network using routing and combined WA and IV.

Abstract: N optical transceivers are each connected to a respective electronic module in one-to-one relation such that a respective one electronic module controls a respective one optical transceiver. An electronic switch matrix provides cross-connect capability between the P redundant electronic modules and N electronic modules to the N optical transceivers. A system controller determines when an active N electronic module has failed, and configures the electronic switch matrix to switch a P redundant electronic module into the optical transceiver to which the failed electronic module was connected. A system switch module redirects traffic and routing information, under the direction of the system controller, from the failed module to the newly activated redundant module so that the redundant module assumes the functionality of the failed module.

Abstract: In a control frame processing unit (14), the number of control frames from a frame demultiplexing unit (13) is counted for each of LLIDs given to the control frames. If the number of frames during a predetermined count period is equal to or smaller than a preset threshold, some or all of the control frames are written in a storage device (30) as processing data. When the number of frames has exceeded the threshold, writing data of the control frames having the LLID in the storage device is stopped. Hence, even when the number of control frames from ONUs increases, software processing can be executed properly.

Abstract: A system and method for monitoring a structure and for distinguishing between an alarm condition, and a nuisance event such as rain. An optical fibre sensor (20,22) produces a signal indicative of a disturbance and level crossing rates are determined to distinguish between noise in the signal (nuisance event) and a required event. A FFT technique is also disclosed as well as classification of an event by extracting predetermined features from the signal.

Abstract: An optical communications system includes a MSAP and an optical transceiver mounted at the MSAP that communicates over an optical network to at least one optical network terminal (ONT). A first electronic module is operatively connected to the optical transceiver and configured to control the optical transceiver and mounted at the MSAP separate from the optical transceiver. A redundant second electronic module is supported within the MSAP and mounted separate from the optical transceiver. A Mux/Demux module interconnects and supports the first and second electronic modules to form an integral unit and mounted at the MSAP separate from the optical transceiver. The Mux/Demux module is configured to switch the second electronic module into communication with the optical transceiver upon failure of the first electronic module.

Abstract: An adaptive equalizer includes a finite impulse response filter with a predetermined number of taps; and a tap coefficient adaptive controller having a register to hold tap coefficients for the filter, a weighted center calculator to calculate a weighted center of the tap coefficients, and a tap coefficient shifter to shift the tap coefficients based on a calculation result of the weighted center. During an initial training period, the tap coefficient shifter shifts the tap coefficients on a symbol data basis such that a difference between the calculated weighted center of the tap coefficients and a tap center defined by the number of taps is minimized.

Abstract: A method of distinguishing a wavelength-dependent reflective element (HRD) from wavelength-independent events in an optical network, the reflective element (HRD) being highly-reflective at a first predetermined wavelength (?1) and significantly less reflective at least one other predetermined wavelength (?2), comprising the steps of: connecting the wavelength-dependent reflective element (HRD) to said optical path at a first position, and, using an optical time domain reflectometer (22) connected to said optical path at a position remote from said reflective element, launching into said optical path light at said first wavelength (?1) and at said second wavelength (?2), detecting corresponding backreflected light from said optical paths and obtaining therefrom first and second OTDR traces (OTDR-?1, OTDR-?2) corresponding to said first (?1) and second (?2) wavelengths, respectively, of detected backreflected light as a function of optical distance from said point; comparing the first and second OTDR traces to

Abstract: Two or more optical transceivers coupled to each other by an optical link to optimize communication over the optical link. A first transceiver generates electrical data that represents an operational parameter for optimization. The transceiver then converts the electrical data into an optical signal and transmits the optical signal over the optical link to a second transceiver. The second transceiver recovers the electrical data from the optical signal and uses the recovered electrical data to change characteristics of the optical signal transmitted by the second transceiver.

Abstract: In one embodiment, an event impact signature detector may analyze a time series with external events. A data interface 250 may receive a data set 310 representing the time series with external events. A processor 220 may fit the data set 310 into a baseline time series model 330. The processor 220 may iteratively determine each event location 352 for multiple external events 350 affecting the baseline time series model 330. The processor 220 may iteratively solve for each event impact 354 of the multiple external events 350 factoring in interactions between the multiple external events 350.

Abstract: Compensation for in-phase (I) and quadrature (Q) timing skew and offset in an optical signal may be achieved based on the correlation between derivatives of I and Q samples in the optical signal. The magnitude of the correlation between derivatives is measured to determine the presence of skew. Correlation between derivatives may be coupled with frequency offset information and/or with trials having additional positive and negative skew to determine presence of skew. Correlations are determined according to pre-defined time periods to provide for continued tracking and compensation for timing skew that may result from, for example, thermal drift.

Abstract: In one example embodiment, an optoelectronic communications assembly having an optical receiver or an optical transmitter includes an optical interface disposed at an end thereof and through which optical signals are communicated by the optical receiver or optical transmitter. The optoelectronic communications assembly also includes an electronic component and a first electrical interface disposed at the optical interface end of the optical communications assembly and communicatively coupled to the electronic component.

Abstract: An optical communication system supporting detection and communication networks. A communication network transmission path and the detection network transmission path are provided as separate paths established by separate fibers or fiber pairs of the same optical fiber cable. All of the elements coupled to the communication network transmission path and the detection network transmission path may be powered by the same power feed equipment through the same optical fiber cable power conductor.

Abstract: The present invention relates to communications technologies, and discloses a method for monitoring the state of a fiber line, a repeater, and a submarine cable system. The repeater includes a first optical amplifier (OA), a second optical amplifier, a first gating unit, a second gating unit, a first coupler, a second coupler, a third coupler, and a fourth coupler. The first coupler, the fourth coupler, and the first gating unit form an in-to-in loopback path between the input end of the first OA and the input end of the second OA; and the second coupler, the third coupler, and the second gating unit form an out-to-out loopback path between the output end of the first OA and the output end of the second OA.

Abstract: A system and method for managing the selection of ghost channels in an optical communication system, including components configured to collect one or more first data values indicating the validity of an optical communication channel within a first degree of a node in the optical communication system, collect one or more second data values indicating the optical power level of the optical communication channel, transmit the first and second data values to a second degree of the node, receive the first and second data values at the first degree, and aggregate the first and second data values for the first degree and the second degree at the first degree.

Abstract: The invention provides a system and method for measuring optical signal-to-noise-ratio (OSNR) in an optical communication system. A channel filter is adapted to select one specific optical communication channel from a wavelength-division-multiplexing (WDM) optical communication system, wherein the channel comprises an optical signal carrying digital bit information and noise from associated optical power amplifiers in the system. At least one optical delay interferometer is adapted to measure at least two interferograms of the noisy signal. The invention provides a mechanism for calculating the in-band OSNR from extinctions of the interferograms measured at different optical delays by referring to each other, wherein said optical delays are selected to be substantially less than a bit period of the optical channel.

Abstract: For determining OSNRreal of a real optical signal carried in an optical network link, the following has been proposed: tapping a portion of the real optical signal, altering the tapped signal portion by adding to it in-band artificial noise signal, thus obtaining a combined signal, scattering the combined signal by stimulated Brillouin or Raman scattering (SBS or SRS) in an optical element, extracting a signal back reflected by SBS/SRS from the optical element, determining OSNRcomb of the back reflected signal and deriving the OSNRreal from the OSNRcomb knowing absolute and/or relative power of the added artificial noise.

Abstract: A fiber optic network reduces distortion present in modulated optical signals received at an optical receiver from an optical transmitter via a fiber optic link. The optical receiver analyzes a received modulated optical signal, where the wavelength of the received signal is periodically varied at the transmitter around a center wavelength over a wavelength range. Based on the analysis, the receiver generates a link transmission curve indicative of the optical power of the received signal over the wavelength range. The network disclosed herein subsequently uses the link transmission curve to reduce the distortion caused by misalignment between the operating wavelength of a transmitter laser and a peak power wavelength at the peak power of the link transmission curve. For example, the transmitter may adjust the laser operating wavelength based on a control signal received from the receiver and generated at the receiver based on the link transmission curve.

Abstract: A system is provided for identifying signal propagation information. The system includes at least one component configured to receive an optical input signal and to emit an optical output signal. The emitted optical output signal is representative of the optical input signal, and is associated with characteristic information indicative of the component. A processor is also included, the processor being configured to sense the optical output signal and correlate the characteristic information with said component.

Abstract: A computerized system and method for managing a passive optical network (PON) is disclosed. The system includes a detection and analysis module adapted for receiving uploaded measurement data from an optical line terminal (OLT) and at least one optical network terminal (ONT), and at least one of technical tools data, service failure data, and outside plant data. The detection and analysis module is adapted for determining a source of failure or potential failure in the PON by correlating the uploaded measurement data and the at least one of technical tools data and service failure data with information stored in a memory medium for the OLT and each ONT.

Abstract: The invention relates to a network comprising at least one host device having an interface card connected to a backplane of said host device, wherein said interface card comprises at least one cage for receiving a pluggable module which performs a traffic management of data transported via at least one optical fiber connected to said pluggable module.

Abstract: A communication system includes a transmitter that combines and transmits a first signal light and a dummy light having a wavelength different from the first signal light; a first amplifier that amplifies a light transmitted by the transmitter to a constant power; a communication device that separates the dummy light from the light amplified by the first amplifier, has a variable transmittance and allows the separated dummy light to pass through, and combines and transmits the passed dummy light and a second signal light having a wavelength different from the dummy light; a second amplifier that amplifies a light transmitted by the communication device to a constant power; a receiver that receives the second signal light included in the light amplified by the second amplifier; and a controller that controls the transmittance.

Abstract: The invention relates to a method for monitoring a passive optical network having a tree-like structure with a main line and a plurality of branches. The method includes transmitting a wake-up signal from an optical line termination (OLT) arranged in the main line to a plurality of monitoring units arranged in the branches. The method also includes detecting the wake-up signal and listening to information requests from the OLT in the monitoring units during a listening time interval after the detection of the wake-up signal. The method further includes transmitting an information request to be received in the listening time interval from the OLT to the monitoring units. The method additionally includes receiving the information request in the monitoring units during the listening time interval, one of the monitoring units which is addressed by the information request transmitting a response message back to the OLT.

Abstract: An optical noise monitoring method and monitor, the monitor comprising an optical transmitter for receiving at least a portion of an optical signal, a device arranged to extract a reflected optical signal comprising a portion of the optical signal back-reflected by stimulated Brillouin scattering in the optical transmitter, and a photodetector for receiving the reflected optical signal. The optical transmitter can scatter the optical signal by stimulated Brillouin scattering.

Abstract: A method for arranging relay stations in an optical transmission system including relay stations arranged so that optical signals at a first transmission speed can be transmitted from a transmission end to a reception end, includes: judging whether a transmission of optical signals at a second transmission speed different from the first transmission speed in a section connecting arbitrary two of the relay stations where a regenerative repeater station capable of regenerating optical signals can be arranged is possible; determining a combination of sections judged to be capable of performing transmission that enables a transmission of optical signals from the transmission end to the reception end; and making both ends of respective sections of the determined combination be the relay stations where the regenerative repeater station is arranged, wherein the judging includes a judgment condition which is satisfied in a section including sections but unsatisfied in one of the sections.

Abstract: A WDM optical transmission system includes a plurality of optical nodes optically coupled by a transmission line, a processor that is operative to calculate an amount of adjustment of a reception level capable of increasing an optical signal-to-noise ratio for each channel of the WDM light reaching the optical node positioned at a receiving end of the unit section based on information on amplification operation of the WDM light in at least one optical-amplification repeating node disposed on the optical transmission line in the unit section, and to adjust a power level corresponding to each channel of the WDM light transmitted on the transmission line from the optical node positioned at a transmission end of the unit section in accordance with a calculation result of the calculation.

Abstract: The invention relates to a network comprising at least one host device having an interface card connected to a backplane of said host device, wherein said interface card comprises at least one cage, for receiving a pluggable module which performs signal processing of data comprised of at least one WDM channel transported via at least one optical fiber connected to said pluggable module in the optical domain.

Abstract: A wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT) is provided. The wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT), includes: a WDM-TDM converter configured to convert a WDM downstream optical signal that is received from a central office terminal (COT) into a TDM downstream optical signal or to convert a TDM upstream optical signal that is received from an optical network terminal (ONT) into a WDM upstream optical signal; an error detector configured to detect an error; and a controller configured to, in response to an error being detected, transmit the WDM upstream optical signal to the COT via a first standby link or transmit the TDM downstream optical signal to the ONT via a second standby link.

Abstract: A wavelength selective switch includes a substrate. On the substrate, the wavelength selective switch includes at least one input port, a dispersive element, a light converging element, a light deflecting member, an output port, and a driving mechanism which drives at least one of the dispersive element, the light condenser element, and the light deflecting member, and drive by the driving mechanism is a rotational drive around an axis perpendicular to the substrate, for the dispersive element, and is a translational drive in a direction of dispersion of wavelength with respect to the substrate, for the light condenser element or the light deflecting member.

Abstract: An apparatus comprising an optical transmitter, a coarse tuner coupled to the optical transmitter and having a first tuning range, a fine tuner coupled to the optical transmitter and having a second tuning range smaller than and within the first tuning range, a wavelength division demultiplexer coupled to the optical transmitter and to a plurality of optical fibers, and a detector coupled to the optical transmitter and the wavelength division demultiplexer. A network component comprising at least one processor configured to implement a method comprising detecting an Optical Time Domain Reflectometry (OTDR) signal spectrum that has a modulated pattern, and detecting a reflected OTDR signal spectrum that has a shifted modulated pattern comprising a frequency shift with respect to the OTDR signal spectrum and a time shift proportional to the frequency shift.

Abstract: A span loss monitoring system includes a supervisory signal sending apparatus with a output level monitoring section, a time stamp generation section, and a supervisory signal generation section that generates a supervisory signal including a pair of the output level measurement hour and the output level. The span loss monitoring system also includes a supervisory signal receiving apparatus with an input level monitoring section, a supervisory signal termination section and a span loss calculation section.

Abstract: System for connecting a plurality of digital subscribers to a data network, comprising a local part connected, by an optical fiber link, to a remote part. Said local part comprises a plurality of DSLAM line cards with xDSL over fiber transceiver that, in turn, comprise a plurality of xDSL lines comprising a modified analog front end which comprises an digital-analogue converter to transform a transmitted digital downstream signal into an analogue downstream signal; an oscillator which fixes an oscillation frequency for the xDSL line; a mixer, directly connected to the output to convert the analog downstream signal into the oscillation frequency; and a band pass filter centered at the oscillation frequency which filters the converted analog downstream signal.

Abstract: An optical layer monitoring apparatus and method thereof are provided. According to an embodiment of the present invention, an optical layer monitoring apparatus including an optical time domain reflectometer (OTDR) function so as to monitor an optical path of a passive optical network (PON), and a method for improving accuracy of measured monitoring results using the optical layer monitoring apparatus are provided. Therefore, it is possible to enable a user to continuously detect distortion or attenuation along the optical path, and to quickly recover from the distortion or attenuation along the optical path when distortion or attenuation is detected.

Abstract: A bit error generating device includes a light source, an input device, and a control processor. The control processor includes logic configured to: receive protocol or bitrate information regarding a live traffic signal via the input device; determine bit error simulation signal parameters based on the received protocol or bitrate information; configure the light source to generate the bit error simulation signal based on the bit error simulation signal parameters; and instruct the light source to inject the bit error simulation signal into an optical fiber carrying the live traffic signal.

Abstract: An optical amplifier using the evanescent light to control the optical output level is provided. The optical amplifier includes: a waveguide path transmitting an optical signal; an optical amplification unit formed on the waveguide path and amplifying the optical signal by an excitation light; an irradiation unit irradiating the excitation light to the optical amplification unit; an optical detection unit generating an electric signal which corresponds to a detected light; a branching unit branching an evanescent light being the optical signal outputted from the optical amplification unit and leaked outside the waveguide path, and focusing the evanescent light on the optical detection unit; a wavelength detection unit detecting a wavelength multiplicity of the optical signal based on the detected evanescent light; and a light amount adjustment unit adjusting a light amount of the excitation light irradiated by the irradiation unit based on the wavelength multiplicity.

Abstract: An apparatus for driving a wavelength-independent light source is provided. The apparatus includes a seed light signal generation unit configured to generate seed light signals with one or more wavelengths based on a wavelength identification signal, a wavelength light detection unit configured to detect the wavelength identification signal from the seed light signals, an extraction unit configured to extract wavelength information corresponding to the detected wavelength identification signal and extract a driving condition of a wavelength-independent light source corresponding to the extracted wavelength information, and a driving unit configured to drive the wavelength-independent light source according to the extracted driving condition.

Abstract: A polarized-wave-multiplexing optical transmitter including: an optical combiner generating a polarized-wave-multiplexed optical signal by polarized-wave-multiplexing a first optical modulation signal and a second optical modulation signal; an optical power fluctuation portion fluctuating optical power of the first optical modulation signal and the second optical modulation signal periodically; a total-optical-power detection portion detecting fluctuation amount of total optical power of the polarized-wave-multiplexed optical signal; and an optical power controller reducing an optical power difference between the first optical modulation signal and the second optical modulation signal based on detection result of the total-optical-power detection portion.

Abstract: A power-saving mode flag generating unit 101e sets a power-saving mode flag to active (non power-saving mode, turning on the power-source) when it receives a reset signal from a MAC unit 102. Furthermore, the power-saving mode flag generating unit 101e sets the power-saving mode flag to sleep (power-saving mode, turning off the power source) in accordance with a signal-interrupt detection signal obtained by the signal-interrupt detecting unit 101f1 of the packet monitoring unit 101f. Depending on the state of a packet, the power-saving mode flag generating unit 101e changes the power-saving mode flag to active or sleep for the data communication area of the packet; however, for the ranging area of the packet, the power-saving mode flag generating unit 101e always sets the power-saving mode flag to active. A pattern discriminating unit 101g discriminates between the data communication area and the ranging area of the packet.

Abstract: An Optical Transport Network (OTN) transient management method, OTN node, and OTN network includes operating an OTN connection in a first mode in a network, the OTN connection traverses at least two nodes in the network, requesting a change in the OTN connection to a second mode which will cause a network transient, the change includes a timing change on the OTN connection affecting the at least two nodes, and performing transient management at the at least two nodes to mitigate the network transient, the transient management prevents spurious alarms due to the change between the first mode and the second mode.

Abstract: An optical splitter for a passive optical network for telecommunication signal transmission with an optical line terminal includes a wavelength selective optical electrical converter, an AC/DC splitter, an energy reservoir and optical switches, where the splitter comprises also a data transmission processing module by which the optical switches can be controlled according to data signals transmitted from the optical line terminal.