Para-alkylated substituted diphenylamines are made by catalytically alkylating diphenylamine with a branched-chain alkene, such as propene, oligomer mixture in which the oligomer present in the greatest percentage has 15-24 carbon atoms. The alkylated diphenylamines are useful crankcase lubricant additives such as for reducing piston deposits and engine sludge.

The invention relates to a machine part comprising a first physical component, wherein: the first physical component is configured for moving relative to a second physical component; the first physical component has a first surface with a contact area for physical contact with the second physical component; the first physical component is shaped spatially complementarity to the second physical component at the contact area, and a polyelectrolyte layer is present on the first surface at a location of the contact area. The invention further relates to a machine comprising the present machine part and the second physical component. In addition, the invention relates to the use of a polyelectrolyte layer to reduce the friction between the first physical component and the second physical component, and a rolling-elements bearing.

The refrigerating machine oil of the invention includes an ester of a polyhydric alcohol and a fatty acid, wherein the molar ratio of C4-C6 fatty acid and C7-C9 branched fatty acid in the fatty acid is between 15:85 and 90:10, the C4-C6 fatty acid includes 2-methylpropanoic acid, and the ratio of the total C4-C6 fatty acid and C7-C9 branched fatty acid in the total fatty acids composing the ester is at least 20 mol %. The working fluid composition for a refrigerating machine according to the invention comprises the refrigerating machine oil, a difluoromethane refrigerant and/or an unsaturated fluorinated hydrocarbon refrigerant.

The invention provides a lubricating composition containing (a) 0.001 wt % to 15 wt % of a polymer with radial or star architecture; (b) an overbased detergent; (c) a dispersant; and (d) an oil of lubricating viscosity. The invention further provides a method for lubricating a mechanical device with the lubricating composition.

A lubricating oil composition comprising (a) a major amount of an oil of lubricating viscosity; and (b) an oil soluble epoxide compound having the following structure: wherein X is hydrogen or a substituted or unsubstituted C1 to C20 hydrocarbyl group, wherein the substituted hydrocarbyl group is substituted with one or more substituents selected from hydroxyl, alkoxy, ester or amino groups and Y is —CH2OR, —C(═O)OR1 or —C(═O)NHR2, wherein R, R1 and R2 are independently hydrogen or C1 to C20 alkyl or alkenyl groups; and further wherein the oil of lubricating viscosity does not contain a carboxylic acid ester.

An internal-combustion engine lubricating oil composition has a P content of not greater than 0.09 mass %; a S content of not greater than 0.3 mass %; and a sulphated ash content of not greater than 1 mass %. It contains the following additives: as sole ashless, nitrogen-containing dispersant, and providing from 0.03 to 0.07 mass % of nitrogen in the lubricating oil composition, at least one ashless, nitrogen-containing derivative of a polyalkenyl-substituted mono- or dicarboxylic acid, anhydride or ester, the polyalkenyl-substituted mono- or dicarboxylic acid, anhydride or ester being made from a polyalkene exclusively by the thermal “ene” reaction; as sole overbased metal detergent, at least one overbased alkaline earth metal sulfonate; and at least one viscosity modifier.

A novel molybdenum dithiocarbamate composition is produced by preparing a di-tridecylamine (DTDA) intermediate from a butylene feedstock comprising greater than 50% 2-butylene, and preparing a molybdenum dithiocarbamate composition from the DTDA intermediate. The resulting molybdenum dithiocarbamate composition are according to formula (1), wherein R1 to R4 are C11-C14 isoalkyl groups, and X represents oxygen and/or sulfur atoms, and R1 to R4 comprise, on average, greater than 98% C13:

Disclosed herein are compounds of formula I: X-(L-Z)p-L-R[L-(Z-L)p-Y]q (I) wherein L is a perfluoropolyether; R is q can be an integer equal to or greater than 1; p can independently be integers from 0 to 7; X and Y can independently be chosen from: —OH, —CH2CH2OH, CH2CH2OCH2CH2OH, —CH2CH(OH)CH2OH, —C6H5, —CH2C6H5, —CH2CH(OH)CH3, F, —CF3, —CF2CF3, piperonyl, triazine, benzotriazole, and derivatives thereof; and Z, if present, can independently be chosen from: —C6H4—, —CH2C6H4CH2—, —CH2CH(OH)CH2—, —CH2CH(OH)CH2CH(OH)CH2—, —CH(OH)CH(OH)CH2—, —CH(CH2OH)—, or —CH(C6H5)—.

A method for screening a lubricating oil composition having at least one base oil of lubricating viscosity and at least one lubricating oil additive is provided, the method comprising the steps of (a) inputting into a computational device an amount of each of the at least one lubricating oil additive, based on the total weight of the lubricating oil composition and, optionally, a value of at least one property associated with each of the at least one base oil of lubricating viscosity; (b) computing a prediction of at least one lubricating oil composition property-determining test result for the lubricating oil composition; (c) computing a cost for the lubricating oil composition; and (d) outputting the results. Also provided are systems and computer program devices for screening lubricating oil compositions.

The present invention is directed to a method for improving one or more of the control of deposit formation and friction in an engine lubricated using a lubricating oil comprising a base oil and additives by employing as the additive the necessary combination of a borated hydroxyl saturated hydrocarbyl ester amide-amine mixture, zinc dialkyl dithiophosphate, and metal salicylate detergent, the deposit formation and friction being improved as compared to a lubricating oil containing the borated hydroxyl saturated hydrocarbyl ester amide-amine mixture, zinc dialkyl dithiophosphate and a detergent other than metal salicylate, such as metal phosphate and/or metal sulfonate.

[Object] To provide a nanoparticle-containing lubricating oil composition which demonstrates a low friction coefficient and realizes a further fuel economy. [Solving Means] A nanoparticle-containing lubricating oil composition comprising a base oil, an additive having hydroxyl group, and nanoparticle. A nanoparticle-containing lubricating oil composition comprising a base oil, an ashless friction modifier having hydroxyl group, and nanoparticle. A nanoparticle-containing lubricating oil composition comprising a base oil, an additive having hydroxyl group, and nanoparticle having a particle diameter of 1 to 100 nm. A nanoparticle-containing lubricating oil composition comprising a base oil, an ashless friction modifier having hydroxyl group, and nanoparticle having a particle diameter of 1 to 100 nm.

A lubricating oil composition comprising a Group II basestock and a neutral or overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of less than 2.

Systems and methods are provided for hydroprocessing a petroleum fraction, such as a bottoms fraction from a fuels hydrocracking process, to generate a lubricant base oil. A fuels hydrocracking process typically has less stringent requirements for the sulfur and nitrogen content of a feed as compared to a lubricant base oil. Additionally, depending on the nature of the feed for the fuels hydrocracking process, the bottoms fraction may contain a relatively high level of aromatics compounds. The aromatic content of such a petroleum fraction can be reduced using a aromatic saturation stage with multiple catalyst beds, or alternatively using a reactor (or reactors) with multiple aromatic saturation stages. The catalysts in the various beds or stages can be selected to provide different types of aromatic saturation activity. An initial bed or stage can provide activity for saturation of 1-ring aromatics in the petroleum fraction. One or more subsequent beds or stages, operating at successively lower temperature, can then be used to reduce the multiple-ring aromatic content of the petroleum fraction.

An oil-soluble lubricating oil additive composition comprising (a) at least 3.5 wt-% of at least one friction modifier selected from the group consisting of fatty acids, fatty acid amides, fatty acid esters, and alkane diols which have a melting point of greater than 30° C.; (b) at least 10 wt-% actives dispersant; and (c) a sufficient amount of surfactant to make said additive composition haze-, sediment-, and skin-free, provided that said additive composition contains at least 150 mm surfactant per kg of said lubricating oil additive composition.

A water-soluble metalworking oil agent is provided by blending the following components A, B, C and D: (A) at least one of a condensed fatty acid obtained by dehydration-condensing a ricinoleic acid, and a condensed fatty acid obtained by dehydration-condensing a monovalent carboxylic acid with an alcoholic hydroxyl group of a condensed fatty acid obtained by dehydration-condensing a ricinoleic acid;(B) an ester compound provided by a dehydration condensate of a monovalent or multivalent alcohol and a monovalent carboxylic acid;(C) an amine compound; and(D) water. A blend ratio of the component A is 10 mass % or more of a total amount of the oil agent and a blend ratio of the component B is 5 mass % or more of the total amount of the oil agent.

It is known by the inventor that a universal synthetic lubricant additive that can greatly enhance the performance standards of existing lubricants, petroleum based or synthetic, imparts a new and desirable property not originally present in the existing oil or it reinforces a desirable property already possessed in some degree can greatly benefit the consumer. Although additives of many diverse types have been developed to meet special lubrication needs, their principal functions are relatively few in number. This universal synthetic lubricant additive (invention) with micro lubrication technology, when used as directed will reduce the oxidative or thermal degradation of the host oil, substantially reduce the deposition of harmful deposits in lubricated parts, minimize rust and corrosion, control frictional properties, reduce wear, temperature, sludge, varnishes and prevent destructive metal-to-metal contact, reduce fuel consumption and harmful emissions while improving performance through increased horsepower and torque.

The present invention relates to a method of driveline device by supplying to the driveline device a lubricating composition containing an oil of lubricating viscosity and an antiwear package, wherein the antiwear package includes: (a) derivatives of a carboxylic acid (typically a hydroxycarboxylic acid); and (b) a phosphorus compound. The invention further provides lubricating compositions containing an oil of lubricating viscosity and an antiwear package, wherein the antiwear package includes (a) derivatives of a carboxylic acid (typically a hydroxycarboxylic acid); and (b) an amine or metal salt of a phosphorus compound that is either (i) a hydroxy-substituted di-ester of (thio)phosphoric acid, or (ii) a phosphorylated hydroxy-substituted di- or tri-ester of (thio)phosphoric acid.

Provided are a lubricant composition capable of reducing friction between sliding parts at least one of which contains an aluminum-based material in a lubrication section, and a method for lubricating an aluminum-based member with the composition. The lubricant composition is for use in a lubrication section having sliding parts at least one of which contains an aluminum-based material, and contains a lubricant base oil and at least one of a phosphorus-containing carboxylic compound and a metal salt thereof (component (A)) at 0.001 to 1 mass % of the composition in terms of phosphorus. The composition may suitably be used as lubricant such as drive train lubricant for automatic or manual transmissions, grease, wet brake oil, hydraulic actuation oil, turbine oil, compressor oil, bearing oil, refrigerant oil, and the like used in apparatus having the sliding parts.

The invention relates to a process for producing ketones or hydrocarbon base oil from fatty acids preferably derived from a biological origin or other renewable source. The process is directed at making an aliphatic ketone or a mixture of aliphatic ketones having 14 to 52 carbon atoms, comprising a ketonization reaction of a fatty acid in a vapor phase with a decarboxylation-coupling catalyst to provide ketones, which can be deoxygenated to give saturated hydrocarbons, unsaturated hydrocarbons, and mixtures thereof. Base oils and transportation fuels may be produced from the process herein.

There is provided an automatic tool changer which, in a precision roll turning lathe which feeds a tool post at a high speed, can automatically change a tool, such as a cutting tool, without stopping the machine, thereby enabling highly efficient ultra-Precision machining of a roll mold for molding of a large-sized plastic sheet. The automatic tool changer includes: a change device including a vertically movable pivot arm having a pivot axis and which pivots in a horizontal plane, a hand portion, mounted at the front end of the arm, for detachably gripping a tool holder, a pivot drive section for pivoting the pivot arm, and a lifting drive section for vertically moving the pivot arm; a tool holder stocker, having a plurality of circumferentially-arranged stages disposed at a predetermined distance from the pivot axis, each stage detachably holding a tool holder; a holder base, mounted to the tool post, for fixing and unfixing a tool holder through the rotation of a clamp shaft; and a clamp shaft operating device including an operating portion for clamping/unclamping the tool holder by rotating the clamp shaft.

A carriage is moved in a direction including a Y axis component in order to move a turning process tool that is attached to a tool spindle along a horizontal line that is perpendicular to a Z axis, and thus, a turning process is carried out on a workpiece which is attached to a workpiece spindle.

A tool stocker includes main stockers for holding a plurality of tools detachably mounted on a main spindle for machining a workpiece, an auxiliary stocker for holding and transferring tools to and from the main stockers, and a tool transfer mechanism for transferring tools between the main stockers and the auxiliary stocker. The auxiliary stocker includes a plurality of tool pods for removably supporting the tools therein, a rail in sliding engagement with outer surfaces of the tool pods, a chain for moving the tool pods in sliding engagement with the rail, and a motor for actuating the chain. The rail has a recess defined therein in alignment with the tool transfer mechanism, such that the tools transferred by the tool transfer mechanism pass through the recess.

A machining installation for workpieces comprises a workpiece positioning device comprising a workpiece holder pivot unit as well as a tool positioning device comprising a tool holder pivot unit. The workpiece holder pivot unit is designed such that a workpiece holder is pivotable about at least three and no more than four workpiece holder pivot axes. Moreover, the tool holder pivot unit is designed such that a tool holder is pivotable about no more than two tool holder pivot axes. The machining installation has a simple design and ensures flexible and accurate machining of workpieces.

A carriage is moved in a direction including a Y axis component in order to move a turning process tool that is attached to a tool spindle along a horizontal line that is perpendicular to a Z axis, and thus, a turning process is carried out on a workpiece which is attached to a workpiece spindle.

A method of voting with your feet is disclosed. A performance of a location-based action by a player of a computer-implemented game is associated with a vote on a matter. The performance of the location-based action by the player is detected. A count of votes corresponding to the vote on the matter is incremented based on the detecting of the performance of the location-based action by the player.

A combination trimming/flame treatment end effector adapted for mounting to the end of a robotic arm. A trimming blade extends from a main body portion of the end effector for performing a trimming operation. The trimming blade may be mounted in an exchangeable cartridge to facilitate blade changing. Also extending from the main body portion is a flame treatment element for performing a flame treatment operation. The flame treatment element generally comprises a torch or burner. Because both the trimming blade and the flame treatment element are part of the same end effector, the robot simply manipulates the end effector such that the desired one of the trimming blade or the flame treatment element is properly positioned for use. As such, a tooling change can be avoided. While not restricted thereto, it is contemplated that an end effector of the present invention may be used to process vehicle bumper fascias.

Disclosed in an automatic tool changer in which the tool changing time can be shortened by increasing overlapping operations of the turning operation and the axial advancing/retracting operation of a replacement arm. An arm driver (32) is so constituted that the driver performs overlapping operations such that at least a part of the operation for turning a replacement arm (23) by 180° and the operation for advancing/retracting the replacement arm in the axial direction in order to insert or withdraw a tool (37) are performed simultaneously and in parallelism with each other. When the replacement arm (23) is advanced/retracted in the axial direction in order to insert or withdraw a tool, the replacement arm (23) is turned by a predetermined distance in a direction reverse to the direction (so called “normal direction”) for turning the arm by 180° in parallelism with the advancing/retracting operation, and thereafter, the replacement arm (23) is turned in the normal direction.

An automatic collimator changer of a radiation treatment system.

A system for loading/unloading sheets is disclosed, some of which also being of metal, and handling method thereof, serving a laser cutting center. The system includes a pair of rails (1, 2), supported at a preset height above a feeding tray (T) of the cutting center, whereon at least one Cartesian robotized hand is movably mounted, capable of moving along horizontal axes X and Y as well as along a vertical axis Z, mutually orthogonal, and including at least two bridge cranes (3, 4) sliding along the rails (1, 2) each of which supports at least one pair of robotized hands (5-8), and the robotized hands (5-8) have an electromagnetic pick-up head which may be coupled with a suction-cup device (103). Feeding tray (T) consists of bars whereon small tesserae (204) of ceramic material are fitted.

There is provided a component mounting apparatus, which includes: a nozzle which sucks a component; a nozzle supporting member, on which the nozzle is installed, which moves in a vertical direction with respect to an upper surface of a substrate on which the component sucked at the nozzle is mounted; an optical system which captures an image of a leading edge portion of the nozzle where the component is sucked in a component mounting operation, from a side direction, such that an optical axis of the optical system is inclined at a predetermined angle with respect to a sucking surface of the nozzle; and an analyzer which analyzes the image of the leading edge portion to determine whether a sucking state of the component sucked by the nozzle is normal or abnormal.

A carriage is moved in a direction including a Y axis component in order to move a turning process tool that is attached to a tool spindle along a horizontal line that is perpendicular to a Z axis, and thus, a turning process is carried out on a workpiece which is attached to a workpiece spindle.

A machine tool is provided with a chain-type bit-storing apparatus which includes a frame, two sprockets, a chain and a pivoting unit. The frame includes a cutout. The sprockets are placed in the frame. The chain is driven by the sprockets. The chain includes links each including a socket for containing a bit, two plates for supporting the socket, first and second blocks placed between the plates, first and second bearing units for rotationally supporting the first and second blocks on the plates, and a connecting unit for pivotally connecting the first block thereof to the second block of an adjacent link. The pivoting unit is used to pivot the socket of a selected one of the links to move an open end of the socket out of the frame through the cutout.

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 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.

The invention provides a vertical turret lathe capable of preventing an inner diameter turning tool attached to a turret tool rest from interfering with a workpiece during machining of the outer diameter of the workpiece. The vertical turret lathe comprises a work table that holds a workpiece W1 and rotates, and a working head 40 having a turret tool rest 50 and capable of moving in X-axis and Z-axis directions. A tool holder 70 for holding an inner diameter turning tool T2 via hydraulic pressure is attached to a part of the tool supporting portions 60 of the turret tool rest. The automatic tool changer apparatus 100 includes a turret-type tool magazine 120 and pistons 160 and 162, which mechanically press the pins 74 and 76 of the tool holder 70 and clamp or unclamp the tool T2.

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.

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 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.

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 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.

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.