A welding tip replacement apparatus is used for a welding torch that includes a tubular tip connection body, a tubular retaining member fitted over the tip connection body, and a tubular welding tip fitted within the tip connection body, the welding torch being configured such that displacing the retaining member toward the proximal end of the tip connection body along the axis of the tip connection body causes the welding tip axially fastened to the tip connection body to be released. The apparatus includes a first grasping mechanism grasping the retaining member, a second grasping mechanism grasping the welding tip protruding from the retaining member in a direction away from the distal end of the tip connection body, a first driving mechanism driving the first grasping mechanism axially, and a second driving mechanism driving the second grasping mechanism axially.

A combination component handling and connecting device connectable to a multi-axis robot for use in moving and connecting components and subassemblies includes a housing and an actuator fixedly connected to the housing. The actuator includes an actuating link movable from a first position to a second position. Connected to the actuating link is an end effector for concurrent movement with the actuating link. The component handling and connecting device includes a clamp having a first jaw and a second jaw. The second jaw is connected to the actuating link for selectively moving the second jaw toward the first jaw operative to engage a component.

A section member drilling or milling machine comprises a machine bed for supporting a workpiece to be drilled, the machine bed including guides for controllably sliding thereon a support comprising precision vertical guides thereon a platform is engaged, the platform comprising parallel horizontal guides slidably supporting a carriage, in turn supporting a cantilever arm, including a driving motor for controllably driving a drilling and milling tool along parallel guides of the cantilever arm.

A tool changing device for a cutting head of a machine for cutting flat glass sheets, the tool changing device comprising: a bridge; a carriage for supporting the cutting head, the carriage being slidingly attached to the bridge for translation along the bridge; an electric motor that provides for translational motion of the carriage with respect to the bridge; and a tool supporting slider, which is configured to support a plurality of tools such that the tools can be automatically exchanged between the tool supporting slider and the cutting head, the tool supporting slider coupled, by way of reversible fixing elements to the cutting head supporting carriage during work by the cutting head, and wherein the tool supporting slider is uncoupled from the cutting head supporting carriage during tool changing operations.

Provided is a module for automatic tool exchange device of novel structure wherein electric signals can be transmitted with high reliability while preventing transmission efficiency from deteriorating between a first coupling member and a second coupling member. An electromagnetic shielding member is arranged on an outer circumference of a core member except for a transmission surface, a gap member having electromagnetic shielding effect lower than that of the electromagnetic shielding member is interposed between the core member and the electromagnetic shielding member, and a first module and a second module are provided, respectively, with coil units equipped with coil heads which are constituted to include a coil member, the core member and the gap member.

A tool radius adjusting device executes an operation for adjusting the tool radius of a boring holder in parallel with execution of a machining program for executing an operation of a spindle head and an operation of a tool changer. A carrier control unit determines whether the tool changer is executing a tool changing process. When the tool changing process is not being executed, the carrier control unit allows the carrier device to execute an operation for picking the boring holder out from the tool magazine and an operation for returning the boring holder, of which the tool radius has been adjusted, to the tool magazine.

The present disclosure relates to a tool gripper chain bendable in two directions that has a chain assembly that includes: gripper blocks that each have a first tooth at the center of a curved groove; first and second gripper assemblies that have first and second gripper members rotatably mounted on the rear of gripper blocks and grip a tool; first and second outer links that are formed in an arc shape; first and second inner links that are formed in an arc shape and disposed zigzag with respect to first and second outer links between first outer link and second outer link; and first and second collars that are disposed between first inner link and second inner link, in which first gripper assembly is disposed in front of second outer link, second gripper assembly is disposed ahead of second inner ink, and a first shaft hole of first gripper assembly and second shaft hole of second gripper assembly are coaxially arranged, such that first and second gripper assemblies are coupled by a first shaft or a second shaft.

Loads that act on all the bearings that support a main spindle are derived from a variation in the state of the main spindle and, in addition, raceway surface contact pressures of the respective bearings are analyzed, so it is possible to accurately keep track of the state of each bearing. Then, when the raceway surface contact pressure exceeds a corresponding threshold, a machining condition is changed to execute control such that the raceway surface contact pressure does not exceed the corresponding threshold, and, furthermore, when the raceway surface contact pressure exceeds the corresponding threshold even when the machining condition is changed, the main spindle is controlled to stop, so it is possible to prevent a seizure of each bearing. Thus, it is possible to improve machining accuracy by controlling the main spindle with high accuracy.

In a multitasking machine tool, a first tool post including a tool spindle configured to allow a tool to be detachably attached thereto is configured to be slidable in predetermined directions, while a second tool post is configured to allow a tool to be detachably attached thereto. A tool-change part includes at least one gripper configured to hold a tool to be attached to the second tool post. An automatic tool changer is configured to detachably attach the tool-change part (as well as to change the tool installed) to the tool spindle of the first tool post positioned in a first tool-change region. Change of the tool attached to the second tool post is carried out by a motion (sliding and/or rotation of the tool spindle) of the first tool post (with the tool-change part attached to the tool spindle thereof) located in a second tool-change region.

In a combination machining lathe, a workpiece holding device holds a workpiece in a manner that permits the workpiece to rotate around an axis parallel to a direction of a horizontal Z axis. A tool post holds a tool that comprises a holder and a bit. The tool held by the tool post is indexed to a position in which the longitudinal axis of the holder is parallel to an X axis direction. The bit of the tool held by the tool post is angled such that a longitudinal axis of the bit is disposed in a position tilted away from the X axis direction closer to a horizontal axis in a plane containing the X axis and the Y axis. A turning operation is performed while the tool and/or the workpiece are moved relative to each other in a direction of the longitudinal axis of the bit.

A network component comprising at least one processor coupled to a memory and configured to exchange security information using a plurality of attributes in a management entity (ME) in an optical network unit (ONU) via an ONU management control interface (OMCI) channel, wherein the attributes provide security features for the ONU and an optical line terminal (OLT). Also included is an apparatus comprising an ONU configured to couple to an OLT and comprising an OMCI ME, wherein the OMCI ME comprises a plurality of attributes that support a plurality of security features for transmissions between the ONU and the OLT, and wherein the attributes are communicated via an OMCI channel between the ONU and the OLT and provide the security features for the ONU and the OLT.

The disclosure provides a method and a system for detecting a fiber fault in a Passive Optical Network (PON). The system comprises an optical path detection device, a Wavelength Division Multiplexing (WDM) coupler, a wavelength selection coupler, a branch fiber selector and a wavelength selection router. The detection system is attached to an original PON system, without influencing the operation of the original system while performing the detection. With the disclosure, the problem of being unable to determine whether there is a fault in a branch fiber due to the loss of an optical path detection reflection signal is solved, the branch fiber with a fault can be quickly located and fixed, thus the operational and maintenance costs of an operator are reduced.

A system and method are disclosed for transporting deterministic traffic in a gigabit passive optical network. A system that incorporates teachings of the present disclosure may include, for example, an Optical Line Termination (OLT) for exchanging data traffic in a Gigabit Passive Optical Network (GPON) having a controller programmed to generate a timeslot schedule for transport of a desired bandwidth of constant bit rate (CBR) data traffic by selecting one or more timeslots from periodic frame clusters operating according to a GPON Transmission Convergence (GTC) protocol. Additional embodiments are disclosed.

A method and apparatus for controlling update of digital pre-distortion (DPD) coefficient is provided. The apparatus is applicable to a digital power control system, wherein the apparatus comprises: an update controlling unit configured to determine a group of fully-trained DPD coefficients among a plurality of DPD coefficients; and a DPD coefficient generating unit configured to update adaptively the group of fully-trained DPD coefficients according to the result of judgment of the update controlling unit. The DPD coefficients are allowed to be updated after being judged as being able to be fully trained according to power distribution information of DPD input signals, or according to address distribution information of an LUT, or according to average power of output of an HPA; otherwise, they may not be updated, thereby efficiently preventing DPD abnormality resulted from unfull training of coefficients in being updated.

Exemplary systems and methods for testing communication media and devices are disclosed herein. An exemplary system may include a transmitting media support and a receiving media support, each including a plurality of communication media. The system may further include a movement support configured to selectively translate the receiving media support relative to the transmitting media support between a transmission position and a free position. In the transmission position, a receiving media may be engaged with the transmitting media to receive an initiated signal from the transmitting media. In the free position, a first end face of the receiving media may be spaced apart from a second end face of the transmitting media, thereby preventing contact between the first and second end faces. The movement support may be further configured to align the at least one of the receiving media with the transmitting media.

The disclosure discloses an apparatus and method for rerouting multiple traffics. The apparatus includes a path computation unit and a traffic path incorporation unit, the path computation unit forwards a received uniform route computation notification message including multiple pieces of failed traffic connection information to the traffic path incorporation unit, and also forwards a route inquiry request transmitted from the head node of the fault traffic to the traffic path incorporation unit; the traffic path incorporation unit analyzes and detects the failed traffic connection information according to traffic incorporating and route inquiry statistic algorithm, and uniformly obtains and records the recovery route information from the path computation unit; when receiving the route inquiry request forwarded by the path computation unit, the traffic path incorporation unit is further configured to search the record according to the route inquiry request, and return the found corresponding recovery route information to the head node which requests the recovery through the path computation unit. The disclosure uses a incorporating and uniform route inquiry method, the resource loss of the path computation unit is reduced, and the efficiency of link restoration is improved.

A multi-channel optoelectronic device is configured to establish a redundant status link with a remote device. The optoelectronic device can transmit N transmit optical signals to the remote device over a plurality of transmit channels and receive N receive optical signals from the remote device over a plurality of receive channels. The optoelectronic device includes one or more spare transmit and receive channels. When used with a remote device having spare transmit and receive channels, each device can establish a status link with the other and use the status link to switch out transmit and/or receive channels to identify and permanently switch out the worst transmit and/or receive channels. Alternately, the device can interoperate with a non-status-link enabled remote device by determining that the remote device is not status-link enabled, transitioning to a low transmit power mode, and transmitting and receiving over a plurality of default transmit and receive channels.

An optical transceiver has a communications mode and an optical time domain reflectometer (OTDR) mode. The transceiver comprises a transmitter channel and a receiver channel operable, in the communications mode, to respectively transmit and receive communications signals through respective external optical fibers. The transceiver also comprises a guide arrangement for guiding, in the OTDR mode, a reflected OTDR signal along a path from the transmitter channel into the receiver channel. A method of obtaining test data for an optical fiber in an optical data communications subsystem is also disclosed.

Methods and systems for decoding a signal include compensating for impairments in a received signal using at least carrier phase estimation, where residual phase error remains after compensation; calculating symbol log-likelihood ratios (LLRs) for symbols in the compensated signal using Monte Carlo integration; demapping the symbols in the compensated signal using the symbol LLRs and extrinsic information from signal decoding to produce one or more estimated codewords; and decoding each estimated codeword with a decoder that generates a decoded codeword and extrinsic information.

Embodiments of the present disclosure provide methods for allocating bandwidth to a plurality of traffic containers of a passive optical network. The method comprises receiving upstream data from a plurality of traffic containers of the passive optical network and passing the upstream data to a traffic manager. The method further comprises dynamically changing the allocated bandwidth based at least in part on the amount of the upstream data stored in one or more queues of the traffic manager.

The invention provides optical interconnects of data-processing cores of multicore chips by means of digital planar holographic microchips. The method comprises delivering “N” laser lights to “N” data-processing cores on the host chip, coding the obtained optical signals by modulating them with the core-generated data, and then delivering the modulated and coded optical signals to a holographic microchip formed on the same substrate of the host chip as the data-processing cores, splitting the modulated and coded optical signals into (N−1)N modulated optical copy signals, delivering the copy signals to all data-processing cores except the one that generates the copy signals, and decoding the data obtained from the output signals delivered to the processing cores by the receivers. The method is efficient in that it allows replacing electrical interconnects between the cores with optical interconnects and can be matched to current semiconductor production technology.

An optical communication system includes an optical-signal transmission unit transmitting an existing optical signal and a low-rate-signal superimposition unit superimposing a low-rate signal on the existing optical signal by intensity modulation. It further includes: a low-rate-signal extraction unit that extracts the low-rate signal from the existing optical signal on which the low-rate signal is superimposed and converts the extracted low-rate signal into a low-rate electric signal; an add-on optical-signal transmission unit that transmits an add-on optical signal; a low-rate-signal superimposition unit that superimposes a low-rate signal on the add-on optical signal by the intensity modulation based on the low-rate electric signal; and a repeater that repeats the add-on optical signal on which the low-rate signal is superimposed, to a transmission destination.

A method of controlling consumer devices using an infrared dongle coupled to a mobile device includes receiving power for the infrared dongle from the mobile device. The infrared dongle includes an infrared transmitter coupled to a microcontroller. One or more instructions are received in the microcontroller from the mobile device. The received one or more instructions are generated from codes stored in a memory of the mobile device. In response to the receiving, one or more infrared signals are transmitted via the infrared transmitter to at least one of the consumer devices.

A transmitter and a receiver for an optical telecommunication system of the WDM type are disclosed. In one aspect, the transmitter uses a chromato-temporal encoder which, with each block of symbols to be transmitted, associates a code matrix, where each element of the matrix corresponds to a wavelength and a use of the channel. The transmitter includes multiple modulators, where each modulator modulates a laser beam at a wavelength during a use of the channel by an element corresponding to the code matrix. The beams modulated in this manner are multiplexed in an optical fiber. Another embodiment using both a wavelength and a polarization encoding is also proposed.

An undersea long-haul transmission system includes an optical fiber transmission span and a coherent detection and digital signal processing module for providing dispersion compensation. The transmission span includes at least one fiber pair comprising substantially equal lengths of a positive-dispersion first fiber and a negative-dispersion second fiber that are configured to provide a signal output at transmission distances greater than 10,000 km, in which the combined accumulated dispersion across the operating bandwidth does not exceed the dispersion-compensating capacity of the coherent detection and digital signal processing module. Further described is a fiber for use in an undersea long-haul transmission span. At a transmission wavelength of 1550 nm, the fiber has a dispersion coefficient in the range of −16 to −25 ps/nm·km, and a dispersion slope in the range of 0.04 to 0.02 ps/nm2·km.

One aspect provides an optical communication system. The system includes an optical-to-digital converter, a frequency estimator and a symbol synchronizer. The optical-to-digital converter is configured to receive an optical OFDM bit stream including an OFDM symbol bearing payload data and a symbol header preceding the OFDM payload data. The frequency estimator is configured to determine a carrier frequency offset of the payload data from the symbol header. The symbol synchronizer is configured to determine a starting location of the payload data within the bit stream by cross-correlating a synchronization pattern within the symbol header with a model synchronization pattern stored by the symbol synchronizer.

A fiber optic data transmission system includes an optical fiber and a data transmitter having a first laser having a first wavelength, a first phase modulator for phase modulating light from the first laser as a function of a first data input stream so as to create a first phase-modulated output data stream, a second laser having a second wavelength different from the first wavelength, and a second phase modulator for phase modulating light from the second laser as a function of a second data input stream so as to create a second phase-modulated output data stream. The transmitter also includes a combiner combining the first and second output data streams into a phase-modulated optical signal for transmission over the optical fiber.

Methods and apparatus related to the detection of low-rate visible light communication (VLC) signals and the recovery of information communicated by the VLC signals are described. Various methods and apparatus are well suited for embodiments in which a device, e.g., a smartphone, including a camera which uses a rolling shutter. The rolling shutter facilitates the collection of different time snapshots of a received low rate time varying VLC signal with different pixel rows in the image sensor of a frame corresponding to different time snapshots. In some embodiments, demodulation is used to recover and identify a single tone being communicated in a frame from among a plurality of possible alternative tones that may be communicated, each different tone corresponding to a different set of information bits.

A pre-emphasis control method includes calculating an average value of transmission characteristics based on transmission characteristics of a plurality of light beams received by a receiver, and determining that, among signals of the plurality of light beams, a wavelength with a deviation from the average value is a wavelength at which control is to be performed, determining that the wavelength at which control is to be performed and a wavelength adjacent thereto are a group of wavelengths at which control is to be performed, obtaining an average of transmission characteristics of the group of wavelengths at which control is to be performed, and based on a difference between averaged transmission characteristics and respective transmission characteristics of the group of wavelengths at which control is to be performed, changing a light intensity output from each transmitter that transmits a group of wavelengths at which control is to be performed.

A signal transmission device drives a light-emitting element and outputs an optical signal depending on a data signal from an electronic device. The device includes an element driving portion which supplies a driving current to the light-emitting element, wherein the driving current is obtained by superimposing a modulation current on a bias current, the modulation current being dependent on the data signal indicating emitting information of the light-emitting element. A temperature compensation portion of the device controls the bias current and the modulation current depending on the temperature so that a temperature-current characteristic of the light-emitting element is reproduced based on the voltage which is dependent on the temperature and the voltage which is independent from the temperature, thereby performing current control depending on the temperature.

Provided is a polarization separation device which converges filter coefficients used in polarization separating process more quickly. The polarization separation device according to the present invention comprises: a first filter means 11 which applies filtering process on each of first and second input signals, which are detected from an received optical signal, with elements of a characteristic matrix representing the inverse characteristics of an optical transmission path as filter coefficients, and uses each of the filtered signals to output a first output signal; a second filter means 12 which applies filtering process on each of the first and second input signals with the other elements of the characteristic matrix as filter coefficients, and uses each of the filtered signals to output a second output signal; a filter coefficient update means 13 which updates the first filter coefficients using a relation between the elements of the characteristic matrix so as to further reduce both error signals of the first and second output signals; and a filter coefficient update means 14 which updates the second filter coefficients using the relation between the elements of the characteristic matrix so as to further reduce both error signals to the first and second output signals.

In one example, an optical channel monitor includes a tunable filter, a deinterleaver, first and second optical receivers, and a control module. The tunable filter is configured to receive an optical signal having a plurality of channels spaced at a nominal channel spacing. The deinterleaver has an input with an input channel spacing Fi, an even output, and an odd output, the input being connected to an output of the tunable filter. The nominal channel spacing is between about one and two times the input channel spacing Fi. A −20 dB bandwidth of the tunable filter is between about two and four times the input channel spacing Fi. The first and second optical receivers are coupled to the deinterleaver even and odd outputs, respectively. The control module is coupled to the tunable filter and is configured to tune the tunable filter to a desired center frequency.

Techniques are provided describing a first connector unit that receives first data from a first transceiver and a second connector unit that receives second data from a second transceiver. A switch unit is configured to receive first switch data from the first connector unit at a first data rate and second switch data from the second connector unit at the first data rate. A third connector unit receives the first switch or the second switch data from the switch unit and a second portion of the second data from the second connector unit. The third connector unit also sends the first switch data to a host port when the first connector unit receives the first data and to send the second switch data and the second portion of the second data to the host port when the second connector unit receives the second data.

An optical transceiver that attenuates the EMI radiation leaked therefrom is disclosed. The optical transceiver includes a top cover and the bottom base to form a cavity into which a TOSA, a ROSA, and a circuit are set. At least one of the top cover and the bottom base provides a combed structure in a rear portion of the optical transceiver, where the combed structure has a plurality of T-shaped fins to attenuate the EMI radiation.

This invention concerns real-time multi-impairment signal performance monitoring. In particular it concerns an optical device, for instance a monolithic integrated photonics chip, comprising a waveguide having an input region to receive a signal for characterization, and a narrow band CW laser signal. A non-linear waveguide region to mix the two received signals. More than one output region, each equipped with bandpass filters that extract respective discrete frequency bands of the RF spectrum of the mixed signals. And, also comprising (slow) power detectors to output the extracted discrete frequency banded signals.

A method and system for providing joint IP/Optical Layer restoration mechanisms for the IP over Optical Layer architecture, particularly for protecting against router failure within such architecture, includes any one of plural node elements participating in the detection and restoration of the joint IP/Optical Layer architecture upon the failure of a router in one of the nodes. The plural node elements may include, but are not limited to, one of plural routers and an optical cross-connect.

Disclosed herein are various embodiments of a time-domain reflectometer having a transmitter configured to apply, to a system under test (SUT), an intensity-modulated probe signal generated based on a periodic pseudo-random bit sequence. The reflectometer further has a receiver configured to receive, back from the SUT, a reflected signal corresponding to the probe signal. The receiver converts the received reflected signal into a binary bit sequence using a relatively simple slicer circuit, and without the use of complex analog circuits and/or multi-bit analog-to-digital converters. The binary bit sequence is then compared with the original pseudo-random bit sequence to obtain a measure of the impulse response of the SUT. In some embodiments, the reflectometer has a controllable noise generator that can be used, e.g., to optimize the obtained measure for the detection of multiple SUT defects having significantly differing reflection characteristics.

An optical transceiver that reduces the EMI radiation leaked therefrom is disclosed. The optical transceiver includes a top cover and the bottom base to form a cavity into which a TOSA, a ROSA, and a circuit are set. The top cover provides a combed structure in a rear portion thereof, where the combed structure has a plurality of fins with a distance preferably less that quarter wavelength λ/4 of the noise wavelength to be reduced. The combed structure operates as a short stub for the electromagnetic wave traveling longitudinally in the cavity.

An apparatus and method for fault indication and localization in a Passive Optical Network (PON) comprising a multistage power splitter (100, 200, 300) with at least one 1:N splitter (120, 221, 222, 321, 322) followed by N items of 2:M splitters (131, 132, 231-233, 331-336), wherein N and M are integers greater than 1. The apparatus also comprises an Optical Time Domain Reflectometry (OTDR) device (110, 210, 310) capable of inserting an OTDR signal into the power splitter (100, 200, 300), and adapted to insert the OTDR signal between the first stage of the at least one 1:N splitter (120, 221, 222, 321, 322) and the second N items of 2:M splitters (131, 132, 231-233, 331-336).

A WDM optical signal is transmitted through a tunable optical filter and is polarization-nulled to find optical signal to noise ratio of individual WDM channels. The polarization nulling can be performed using a heuristic multipoint extrema search method, such as Nelder-Mead method. A plurality of checkpoints can be included in the search to verify the progress and to improve the overall robustness of a real-time polarization nulling.

The present invention refers to a method for adjusting power levels of channels (15) in an optical link (7) of an optical network comprising at least one optical amplifier (9) wherein the power distribution among the channels (15) of the optical link (7) is achieved in function of: target power levels based on the features of corresponding connections and of link physical features,total available power in said at least one amplifier (9),features of control means allowing the power distribution, and wherein for a channel corresponding to a connection having a higher vulnerability characterizing parameter, the tolerated difference between an actual channel power level and the target power level is lower than for a channel corresponding to a connection having a lower vulnerability characterizing parameter.

An optical transport network system includes a plurality of NEs, each transmitting wavelength-multiplexed optical signals. Each NE includes a routing information DB that is used to store reachable area information, which contains identifiers of other NEs in a range within which the optical signals can be transmitted from the own NE without using an REG. A FROM NE includes a path candidate searching unit that searches for a plurality of path candidates for transmitting optical signals from the FROM NE to a TO NE. The TO NE includes a path selecting unit that selects a path for transmitting optical signals from among a plurality of path candidates. The path selecting unit obtains the number of times for which the REG is used for each of the plurality of path candidates; and, based on each number of times that is obtained, selects a path for transmitting the optical signals.

Additional bandwidth is provisioned to layer 2/3 networks by initially provisioning optical wavelength channels to meet incremental needs for additional capacity. When bandwidth requirements grow large enough, a wavelength-sized channel is provisioned to meet the bandwidth needs, and the previously provisioned optical wavelength channels are freed up to be reused for additional growth. The optical wavelength channels may be channelized VLANs mapped to resizable optical channel data units such as ODUflex units.

An optical line termination node has a first connection arrangement for connecting a working fiber, a second connection arrangement for connecting a protection fiber, a transceiver arrangement having first primary link and a first secondary link, and protection switching means configured for being switched either in a working operating state or in a protection operating state.

This invention relates to provisioning wavelength-selective switches and reconfigurable optical add-drop multiplexers to minimize the bandwidth narrowing effect from the optical filters. Novel architectures and methods are disclosed that can significantly reduce bandwidth-narrowing on channels in a reconfigurable WDM network where a large number of optical filter elements are cascaded. Instead of blocking unused channels as in the prior art, unused channels are selectively provisioned depending on the state of their adjacent channels. Unused adjacent channels of an active channel are provisioned to follow the same path as the active channels. As each channels is deployed, the channel frequency is selected so as to minimize bandwidth narrowing.

A method for adjusting an optical signal includes determining a polarization dependent loss (PDL) value associated with the optical signal, determining an angle between the optical signal and one or more axes of PDL, determining an amount of nonlinear phase noise due to PDL and nonlinear effects upon the optical signal based upon the PDL value and the angle, determining a phase rotation based upon the amount of nonlinear phase noise, and applying the phase rotation to the optical signal.

An optical module that outputs a wavelength multiplexed optical signal is disclosed. The optical module provides at least first to third optical source, a wavelength multiplexer, a polarization rotator, and a polarization multiplexer. The optical sources each outputting first to third optical signals with a wavelength different from others. The wavelength multiplexer multiplexes the first optical signal with the third optical signal. The polarization rotator rotates the polarization vector of one of the multiplexed first and third optical signals and the second signal by substantially 90°. The polarization multiplexer multiplexes the polarization rotated optical signal with the second optical signal.

Optical fiber-based distributed communications systems that provide and support both RF communication services and digital data services are disclosed herein. The RF communication services and digital data services can be distributed over optical fiber to client devices, such as remote antenna units for example. In certain embodiments, digital data services can be distributed over optical fiber separate from optical fiber distributing RF communication services. In other embodiments, digital data services can be distributed over common optical fiber with RF communication services. For example, digital data services can be distributed over common optical fiber with RF communication services at different wavelengths through wavelength-division multiplexing (WDM) and/or at different frequencies through frequency-division multiplexing (FDM). Power distributed in the optical fiber-based distributed communications system to provide power to remote antenna units can also be accessed to provide power to digital data service components.

The device identification apparatus includes: a remote controller signal detecting section for detecting an optical signal from a remote controller; a receiving section for receiving the optical signal from the remote controller; a signal decryption section for decrypting the optical signal received by the receiving section; and a transmitting section for transmitting a device identification signal when the optical signal is a device selecting signal, and configured such that operations of the receiving section, the signal decryption section, and the transmitting section are started in response to a detecting signal of the remote controller signal detecting section, thereby realizing a device identification apparatus in which power consumption during standby is minimized.

A laser relay module for free space optical communications including an optical telescope for receiving and transmitting optical beams; an optical diplexer for separating transmitting and received optical beams; an optical amplifier; a modulated beacon laser for line of sight control of a plurality of communicating remote network nodes; a beacon beam detector for detecting an incoming beacon optical beam for line of sight control of the optical telescope and receiving data from other network nodes; and means for inserting an output of the modulated beacon laser into the optical telescope for transmission to another network node, and for transporting the incoming beacon optical beam to the beacon detector.