Abstract: Systems and methods for modulation and demodulation using a micro-Doppler effect are described. In an embodiment, the method includes radiating, using a picosecond pulse generator with an antenna, a train of THz pulses that form a frequency comb, where the frequency comb is reflected from an object such that the frequency several tones in the frequency comb are shifted based on the speed of the object and demodulating the reflected frequency comb to recover a THz Doppler signature of the object.

Abstract: A spatial information capturing device includes a structured light generation module, a camera module and a process controller. The structured light generation module provides a structured light pattern to a target object, so that an evaluation pattern is formed on the target object. The camera module includes a lens group, an optical encoder and a sensing unit. The optical encoder has a reference pattern. The reference pattern and the evaluation pattern have at least one corresponding pattern feature. In addition, both of the reference pattern and the evaluation pattern are projected on the sensing unit. The process controller compares a pattern feature difference between the reference pattern and the evaluation pattern, and realizes a spatial distance information of the target object according to a result of comparing the pattern feature difference. Hence, the configuration or structure of the spatial information capturing device is simplified.

Abstract: Integrated performance monitoring (PM); optical layer operations, administration, maintenance, and provisioning (OAM&P); alarming; amplification, and the like is described in optical transceivers, such as multi-source agreement (MSA)-defined modules. A pluggable optical transceiver defined by an MSA agreement can include advanced integrated functions for carrier-grade operation which preserves the existing MSA specifications allowing the pluggable optical transceiver to operate with any compliant MSA host device with advanced features and functionality, such as Forward Error Correction (FEC), framing, and OAM&P directly on the pluggable optical transceiver. The advanced integrated can be implemented by the pluggable optical transceiver separate and independent from the host device.

Abstract: A waveguide has a front and a rear surface, the waveguide for a display system and arranged to guide light from a light engine onto an eye of a user to make an image visible to the user, the light guided through the waveguide by reflection at the front and rear surfaces. A first portion of the front or rear surface has a structure which causes light to change phase upon reflection from the first portion by a first amount. A second portion of the same surface has a different structure which causes light to change phase upon reflection from the second portion by a second amount different from the first amount. The first portion is offset from the second portion by a distance which substantially matches the difference between the second amount and the first amount.

Abstract: A time-of-flight camera system includes a photosensor having at least one receiving pixel and a source of illumination. A modulator is configured to provide a modulation signal to the photosensor and to the source of illumination. A control sensor is connected to at least one reference light source or an electric mixer. The control sensor is disposed in a vicinity of the source of illumination such that the control sensor receives at least a portion of the radiation emitted by the source of illumination. The control sensor is configured to provide an electric output signal that substantially matches an intensity-over-time curve of the received radiation.

Abstract: We disclose an optical transport system configured to transport an additional data stream using hierarchical modulation. In an example embodiment, copies of the additional data stream are encoded onto enhancement layers of multiple hierarchically modulated optical waves transported through the system in a multiplexed manner. An optical receiver coupled to a remote end of the optical transport link is configured to use this redundant transmission of the additional data stream to improve the bit-error rate thereof, e.g., by first extracting the signal components corresponding to the enhancement layers of the different hierarchically modulated optical waves and then combining the extracted signal components in a manner that tends to reduce, through averaging, the relative magnitude of noise in the combined signal compared to that in the individual extracted signal components. The disclosed signal-transmission format is suitable for various types of multiplexing, e.g.

Abstract: A multiple-input multiple-output (MIMO) capable system is contemplated. The communication system may include a signal processor configured to separate an input stream into multiple signal paths to facilitate simultaneous transport through a communication medium. The capability to simultaneously transmit multiples signal paths may be beneficial in order to maximize throughput and/or minimize expense.

Abstract: A method and apparatus for loading, detecting, and monitoring channel-associated signals are provided. Channel-associated signals are identified with spread spectrum codes in the electrical domain, and after being modulated to an optical service signal at respective loading points separately, the channel-associated identification signals are transmitted in the optical channel along with the optical signal. At any downstream detecting point, passing optical signals can be converted through photoelectric conversion, and the channel-associated identification signals are de-spread. By detecting the channel-associated signals, it is possible to learn about whether the upstream loading point work normally, whether the optical channel operates normally, etc., and thereby to find possible failures, solve problems, and monitor quality parameters of optical signals in real time, and improve reliability of the optical signal transmission.

Abstract: The disclosure provides an optical network system, an Optical Line Terminal (OLT), an Optical Network Unit (ONU) and an Optical Distribution Network (ODN) apparatus. The system includes: an OLT configured to modulate and encode at least one line of time-division-multiplexed downlink signals, synthesize the downlink signals encoded into one line and then output it, receive uplink signals, and decode the uplink signals received and then output them; an ODN configured to separate the downlink signals received into multiple lines and then output them, synthesize the uplink signals received into one line, and then output it to the OLT; and ONUs configured to receive the downlink signals output from the ODN, decode the downlink signals received and output them, encode one line of time-division-multiplexed uplink signals, and output the uplink signals encoded to the ODN. Decoding of the downlink signals and encoding of the uplink signals can further be implemented by the ODN.

Abstract: A Pseudo-Return-to-Zero modulator is provided with a narrow pulse clock generator, a modulator driver, and an optical modulator. The narrow pulse clock generator generates a narrow pulse clock of order n, where one of levels occupies half a symbol period and the other level occupies (n?1) plus half a symbol period, n being equal to or more than two. The modulator driver generates an electrical signal in response to binary data and the narrow pulse clock. The optical modulator modulates an optical carrier in response to the electrical signal so that the modulated optical carrier is in a PRZ(n) format.

Abstract: A high data rate optical signal is inverse multiplexed into a multitude of lower-rate tributaries, each of which is coded by its unique OCDM code, and the combined coded tributaries are injected into a common phase scrambler. Coherent summation of these optically encoded tributaries pass through a shared phase or phase and frequency scrambler before exiting the secure location. The setting of the scrambler acts as the key. The authorized recipient with the correct key retrieves the ones and zeros of the several decoded signals.

Abstract: Data security of a multi-dimensional code system is increased. An optical device is provided with a single input port; a splitter splitting an input light from the input port into a plurality of lights; a plurality of phase shifters each shifting one of the lights split by the splitter; a multi-port encoder/decoder inputting the lights whose phases are shifted by the phase shifters and generating spectral encoded codes; and a plurality of output ports outputting the spectral encoded codes generated by the multi-port encoder/decoder.

Abstract: The invention is directed toward a variable spectral phase encoder. The variable spectral phase encoder includes a plurality of switches and at least one encoder. The encoder is coupled between a first switch and second switch among the plurality of switches. The first switch selectively routes an optical signal to some combination of fixed encoders such that their collective product applies one of the Hadamard sequences to the optical signal.

Abstract: A Distributed Denial of Service (DDoS) attack detection and defense apparatus and method are provided. The Distributed Denial of Service (DDoS) attack detection and defense apparatus includes: a flow information collection unit to collect, from one or more input packets with an IP address of an attack target system as a destination IP address, flow information including source IP addresses of the input packets and packet counts of one or more flows that are classified for each of the source IP addresses and each of different protocol types; an inspection unit to calculate packets per second (PPS) values of the flows based on the packet counts; and a response unit to determine a DDoS attack response method for each of the flows based on the PPS value and the protocol type of a corresponding flow and to process the corresponding flow using the determined DDoS attack response method.

Abstract: A passive optical network communication system includes a number of subscribers' units connected to a central line termination unit through a passive optical coupler. The line termination unit includes a first section that transmits and receives a code division multiplex (CDM) signal, a second section that transmits and receives a time division multiplex (TDM) signal, and a wavelength multiplexing filter that combines the transmitted CDM and TDM signals into a single downstream optical signal, and separates the CDM and TDM components of an upstream signal received from the subscribers' units through the passive optical coupler. The CDM signal provides channels for digital video transmission to CDM-capable subscribers' units.

Abstract: A method and memory medium in a wavelength division multiplexing (WDM) network that communicates multiplexed signals representing a plurality of communication channels to determine received signal quality are disclosed. Generally, the signals format the plurality of communication channels to impart a distinctive noise profile in time or frequency for each channel; and collectively process the channels at a digital signal processing device to measure the signal-to-noise ratio.

Abstract: A complex orthogonal code in the present invention is one in which each row of a square matrix of N rows and N columns in which an element of an mth row and nth column is exp[2?j(m?1)(n?1)/N] (where j is an imaginary unit) is adopted as a code word. An optical orthogonal code for Optical Code Division Multiplexing/Optical Code Division Multiple Access (OCDM/OCDMA) is realized by a train of N-number of optical pulses corresponding to the argument (phase) of the code elements. An optical transmitter or optical receiver includes an optical correlator provided with a sampled Bragg grating having a plurality of Bragg gratings disposed serially at regular intervals inside an optical waveguide. The optical correlator is allocated any one of the code words. In the optical transmitter, an optical signal to be transmitted is encoded by the optical correlator. In the receiver, a received optical signal is decoded by the optical correlator.

Abstract: The invention is directed to code labeling in an optical network. The network includes a transmitting station operable to transmit an optical signal. The network also includes an encoder coupled to the transmitting station operable to label the optical signal composed of a group of codes. A receiving station operable to receive the labeled group of optical codes is also provided. The receiving station is operable to read the optical signal if the label of the received group of codes corresponds to the group of codes assigned to the receiving station.

Abstract: The invention relates to controlling a lighting device, particularly to the modulation of light generated by a solid state lighting (SSL) device. The invention provides a method and device for modulating the light emission of a lighting device by keying each pulse (14) of a sequence of pulses (16) contained in the control signal (10) according to a spreading code. Thus, the light emission of a lighting device may be identified by detecting the spreading code used for modulating the light emission. The invention is particularly suitable for lighting means containing several lighting devices such as a LED lighting board with dozens of LEDs since the light emission of each lighting device may be detected by the spreading code used for modulating the light emission.

Abstract: An optical network having a tree-like structure with a main line and a plurality of branches, at least two of the branches comprising a monitoring unit for upstream signalling to the main line, wherein each of the monitoring units comprises a signal generation unit with a light source for generation of a pre-defined optical signal, and the monitoring units are construed to generate pre-defined optical signals which are different from each other, as well as a monitoring unit for generating a periodic upstream signal in such an optical network and a method for monitoring such an optical network.

Abstract: In a passive optical communication network system, an optical signal OCDM-coded is transmitted from an OLT to a first port of a circulator, which in turn transfers the signal from its second port to one end of a first SSFBG. The first SSFBG then decodes the signal of one channel to output the decoded signal from its one end to the second port of the circulator, which in turn transmits the decoded signal from its third port to an ONU. When the ONU transmits an optical signal to the third port of the circulator, the circulator transfers the signal from its fourth port to one end of a second SSFBG, which in turn encodes the signal to output the encoded signal from its one end to the fourth port of the circulator. The circulator then transmits the encoded signal from its first port to the OLT.

Abstract: An OCDM communication system and a method for correcting failure of the same are provided. In the system, encoders and decoders are provided respectively for channels. Each encoder, including an SSFBG, encodes an optical signal using a code value determined according to distance between adjacent unit fiber Bragg gratings in the SFFBG. Each decoder, including an SFFBG, generates a received optical signal by decoding the encoded signal using a code value determined in the same manner. A set temperature of each encoder and decoder is calculated and a corresponding control signal is generated based on average power and error rate detection signals of each received optical signal. The temperature of each encoder or decoder is individually adjusted according to the control signal, which makes equal the code values of an encoder and decoder of a channel in which average power of a received signal has changed or error rate thereof is excessive.

Abstract: A high data rate optical signal is inverse multiplexed into a multitude of lower-rate tributaries, each of which is coded by its unique OCDM code, and the combined coded tributaries are injected into a common phase scrambler. Coherent summation of these optically encoded tributaries pass through a shared phase or phase and frequency scrambler before exiting the secure location. The setting of the scrambler acts as the key. The authorized recipient with the correct key retrieves the ones and zeros of the several decoded signals.

Abstract: A method and apparatus for loading, detecting, and monitoring channel-associated signals are provided. Channel-associated signals are identified with spread spectrum codes in the electrical domain, and after being modulated to an optical service signal at respective loading points separately, the channel-associated identification signals are transmitted in the optical channel along with the optical signal. At any downstream detecting point, passing optical signals can be converted through photoelectric conversion, and the channel-associated identification signals are de-spread. By detecting the channel-associated signals, it is possible to learn about whether the upstream loading point work normally, whether the optical channel operates normally, etc., and thereby to find possible failures, solve problems, and monitor quality parameters of optical signals in real time, and improve reliability of the optical signal transmission.

Abstract: The invention relates to receiving of a modulated light signal from a lighting device, particularly from a solid state lighting (SSL) device. It is an object of the present invention to provide a receiver and a receiving method which are primarily designed to operate efficiently for light (wave) signals that adhere to specific constraints. In order to achieve this object, the invention provides a receiver for a modulated light signal which is keyed with a code sequence of a predefined number of chips, comprising —a light sensor adapted to receive the modulated light signal and to convert it into an electrical signal, —sampling means adapted to take several consecutive samples of the electrical signal during a chip period, and —processing means adapted for calculating for each sample of a chip period an inner product with the chip.

Abstract: A synchronized CDM communication system performs 1-to-N communication by CDM between a central office and first to N-th optical network units (ONU). The synchronized CDM communication system adds structural elements for realizing a connection state acquisition section to a conventional synchronized CDM communication system. A central office includes a presence check section, a ranging processing section and the connection state acquisition section. The presence check section checks the ONUs that are connected with the central office and the ONUs that are not connected. The ranging processing section performs transmission timing adjustments for the ONUs that are connected. The connection state acquisition section verifies whether all of ONUs are connected with the central office, and performs a discovery of a ONU, among the ONUs that were not connected at the time of the check, that has resumed participation in communication since the check ended.

Abstract: In a PON system, an OLT periodically transmits a channel resource information block specifying a carrier wavelength and a spreading code on a first downstream channel to which a spread-spectrum spreader having a first spreading code is applied; one of ONUs receives the channel resource information block with a spread-spectrum despreader having the first spreading code and transmits a connection request to the OLT, using the carrier wavelength and the spreading code specified by the channel resource information block; the OLT having received the connection request transmits a new channel resource information block specifying a carrier wavelength and a spreading code to be used on an upstream data channel to the requester ONU through the first channel; and the requester ONU transmits data, using the carrier wavelength and the spreading code specified by the new channel resource information block.

Abstract: Super-structured fiber Bragg gratings (SSFBGs) of s optical pulse time spreaders are provided with N unit FBGs disposed starting from an input/output end in the order of first to N-th unit FBGs, where s is a parameter less than or equal to a parameter N, a natural number. The unit FBGs are configured such that the reflectivities of the unit FBGs placed from one end to the center of the SSFBG formed in an optical fiber are monotonically increased, while the reflectivities of the unit FBGs placed from the center to the other end of the SSFBG are monotonically decreased. The chip pulses in a pulse train are given relative phases such that the relative phase of the first chip pulse is equal to zero, the relative phase of the second chip pulse is equal to a phase difference d1=2?{a+(n?1)/N}, . . . , and the relative phase of the N-th chip pulse is equal to (N?1)d1. The parameter a is any real number satisfying the condition of 0?a<1.

Abstract: An optical code division multiplexing signal generator provided with an optical pulse light source, a first encoder to an Nth encoder, a first optical modulator to an Nth optical modulator, and a first optical circulator to an Nth optical circulator. The first optical circulator inputs an input optical pulse train to a first encoder, and inputs a first encoded optical pulse train output by Bragg reflection from the first encoder to the first optical modulator. The kth optical circulator inputs an input (k?1)th optical pulse train which has passed through the (k?1)th encoder to a kth encoder, and inputs a kth encoded optical pulse train output by Bragg reflection from the kth encoder to the kth optical modulator. Herein k takes all integers from 2 to N, and N is a positive integer of 2 or more.

Abstract: An optical communications network in which one optical line terminal is connected to multiple optical network units and in which code division multiplexing communication is carried out between the optical line terminal and the optical network units. The optical intensities of upstream optical signals transmitted from each optical network unit are made constant at the time of multiplexing by an optical directional coupler, and the optical intensity of a downstream optical signal received by an optical network unit and an upstream optical signal received by the optical line terminal is contained within a dynamic range. Each optical network unit is provided with a variable optical attenuator that is common for an upstream optical signal and a downstream optical signal. The upstream optical signal and the downstream optical signal are attenuated by an equal attenuation. Moreover, the optical line terminal controls the attenuation at the variable optical attenuator.

Abstract: A method and apparatus for loading, detecting, and monitoring channel-associated signals are provided. Channel-associated signals are identified with spread spectrum codes in the electrical domain, and after being modulated to an optical service signal at respective loading points separately, the channel-associated identification signals are transmitted in the optical channel along with the optical signal. At any downstream detecting point, passing optical signals can be converted through photoelectric conversion, and the channel-associated identification signals are de-spread. By detecting the channel-associated signals, it is possible to learn about whether the upstream loading point work normally, whether the optical channel operates normally, etc., and thereby to find possible failures, solve problems, and monitor quality parameters of optical signals in real time, and improve reliability of the optical signal transmission.

Abstract: In a fixed delay optical communication system, rate adjustable differential phase shift key (DPSK) techniques eliminate the need for multiple comparing modules, each corresponding to a different data rate. Setting alternative data rates at integer multiples of the fundamental data rate of the optical communication system allows the system to process the respective integer number of symbols per period of the system, wherein the period of the system is the inverse of the fundamental data rate. Pulse carving techniques may be used to set the duty cycle of clock levels associated with a clock signal. The clock levels may be combined with respective symbols to provide optical symbols having a duty cycle less than 100%.

Abstract: An optical transmitting circuit (2) modulates multimode oscillation light using an information signal, subjects at least one oscillation-mode light beam of the multimode oscillation light to a predetermined operation, and outputting the result to an optical transmission channel. An optical receiving circuit (8) receives an optical signal transmitted through the optical transmission channel, subjects the received optical signal to an operation reverse to the predetermined operation to recover an optical signal as it was before being subjected to the predetermined operation, and converting the recovered optical signal into an electrical signal, thereby reproducing the information signal.

Abstract: Methods and apparatuses are provided for transmitting labels in an optical packet network. Groups of K payload bits are encoded into blocks of N bits by using a code in which each of the groups of K payload bits is represented by a corresponding one of at least two distinct codewords of differing weights to form coded payload packet data, where K and N are integers and K<N. Composite packet data is produced by choosing among the at least two distinct codewords according to a value of chip data based, at least partly, on label data. An optical signal for transmission via the optical network is produced by applying the composite packet data to an optical transmitter.

Abstract: A passive optical network communication system transmits an optical time-division multiplexed signal from a central office through a passive optical coupler to a number of subscribers, and transmits optical encoded signals from the subscribers through the passive optical coupler to the central office. Optical encoded signals from different subscribers are separated by a decoding process performed at the central office. All operations can be synchronized with a clock signal which is generated at the central office and recovered from the optical time-division multiplexed signal by the subscribers' equipment. The communication range can be extended inexpensively by using a single high-power light source at the central office while using relatively low-power light sources at the subscribers' equipment.

Abstract: An apparatus and methods for encoding and decoding data are disclosed. The method for transmitting and receiving data allows for coding and decoding each bit of data with a different code. The transmitter and receiver devices allow encoding and decoding, respectively, each bit of data with different a code.

Abstract: An optical pulse time spreading device includes S optical pulse time spreading elements that spread input optical pulses into trains of (N×j) chip pulses, where j is an integer greater than zero, S is an integer greater than one, and N is an integer equal to or greater than S. In the chip pulse trains output by the n-th optical pulse time spreading element (n=1, 2, . . . , S), the light in successive chip pulses is shifted in phase by successive integer multiples of the quantity 2?{a+(n?1)/N}, where a is an arbitrary constant (0?a<1). In an optical code-division multiplexing system, this optical pulse time spreading device produces an autocorrelation wave with a high energy and a high signal-to-noise ratio.

Abstract: Wired/wireless optical signal modulation and demodulation apparatuses and methods using an intensity modulation/direct detection method and an orthogonal frequency division multiplexing (OFDM) method are provided. A unipolar OFDM symbol frame is generated by determining the polarity of each of a plurality of sub-frames of a bipolar OFDM symbol frame which comprises both a plurality of positive pulses and a plurality of negative pulses, inverting the polarity of the sub-frames which are determined to be negative, delaying one of the positive sub-frame and a positive sub-frame obtained through the inversion by the duration of the sub-frames, and multiplexing the result of the delaying and whichever of the positive sub-frame and the positive sub-frame obtained through the inversion is not the result of the delaying. The unipolar OFDM symbol frame can guarantee high power amplification efficiency and high transmission power efficiency, and is robust against a multi-path channel environment.

Abstract: To achieve secure optical communications, a messaging encoding scheme is utilized in which optical communication signals are encoded based upon a known unique code. This encoding methodology allows for the broad transmission across an optical network which will include intended destination. Only the intended destination or destinations will include the necessary unique codes to allow recognition and decoding of the optically encoded message. By providing security in this optical encoding manner, the need for additional message overhead and/or additional systems is thus avoided, thereby providing efficient communication in a secure manner.

Abstract: The invention provides a system and method for secure communication that involves encoding and transmitting an optical communications signal that is encoded based on a multi-dimensional encoding technique. This technique may include at least one or more of encoding a phase, a polarization, and a frequency of the signal. Light encoding is independent from its modulation with data. The data is modulated using any format; in the preferred embodiment the QPSK format is implemented. The encoded and modulated light is transmitted through free space or via a fiber optic network to a receiver, where the information is decoded. A coherent detection based on 90-degrees or 120-degrees optical hybrid is used to decode and recover the data from the received signal. Because the encoding of the transmitted light varies according to a specific pattern or sequence, one without knowledge of the transmission encoding sequence is prevented from decoding the transmitted information.

Abstract: A phase control arrangement has a structure in which a Superstructured fiber Bragg Grating (SSFBG) 40 has fifteen unit Fiber Bragg Gratings (FBGs) arranged in series in a waveguide direction. The SSFBG 40 is fixed to the core of an optical fiber 36 that includes a core 34 and cladding 32. The difference ?n between the maximum and minimum of the effective refractive index of the optical fiber is 6.2×10?5. The phase difference of Bragg reflected light from two unit diffraction gratings that adjoin one another from front to back and provide equal code values is given by 2?M+(?/2), where M is an integer. Further, the phase difference of the Bragg reflected light from two unit diffraction gratings that adjoin one another from front to back and provide different code values is given by 2?M+(2N+1)?+(?/2) where M and N are integers.

Abstract: An OCDM communication system and a method for correcting failure of the same are provided. In the system, encoders and decoders are provided respectively for channels. Each encoder, including an SSFBG, encodes an optical signal using a code value determined according to distance between adjacent unit fiber Bragg gratings in the SFFBG. Each decoder, including an SFFBG, generates a received optical signal by decoding the encoded signal using a code value determined in the same manner. A set temperature of each encoder and decoder is calculated and a corresponding control signal is generated based on average power and error rate detection signals of each received optical signal. The temperature of each encoder or decoder is individually adjusted according to the control signal, which makes equal the code values of an encoder and decoder of a channel in which average power of a received signal has changed or error rate thereof is excessive.

Abstract: An optical transmitting circuit (2) modulates multimode oscillation light using an information signal, subjects at least one oscillation-mode light beam of the multimode oscillation light to a predetermined operation, and outputting the result to an optical transmission channel. An optical receiving circuit (8) receives an optical signal transmitted through the optical transmission channel, subjects the received optical signal to an operation reverse to the predetermined operation to recover an optical signal as it was before being subjected to the predetermined operation, and converting the recovered optical signal into an electrical signal, thereby reproducing the information signal.

Abstract: The invention relates to an aircraft data communication system as well as an aircraft comprising such a data communication system, in particular a wireless optical communication system inside an aircraft cabin and outside for aircraft services. The aircraft data communication system comprises a first sending unit 10 comprising a first sender and a first modulator, and a first receiving unit comprising a first receiver and a first demodulator. The communication system is adapted for a signal transmission between the first sender and the first receiver, wherein the signal transmission between the first sending unit and the first receiving unit is effected by light, and wherein the first modulator is adapted for modulating an amplitude of the transmitted light.

Abstract: Systems and methods are presented herein to achieve data privacy in the optical realm such that electronic encryption bottlenecks are removed, potentially increasing data transmission speeds to the limit of fiber optic media. In this regard, privatizing an optical data transmission may include dynamically altering a temporal length of data bits in an optical data transmission or dynamically altering a temporal length of data frames in an optical data transmission. For example, in a two-dimensional OCDMA signal, the temporal length of data bits may be altered by changing the number of time chips on a per bit basis (e.g., using OCDMA signatures having different temporal lengths). In an optical data bit scrambling signal, the temporal length of data frames may be altered by changing the number of time slices on a per data frame basis.

Abstract: A method and system for averaging the effects of polarization distortions across a multitude of transmitted data streams in a dual polarization multiplexed optical communications system. Data streams are interleaved amongst each other in accordance with a predetermined pattern. The interleaved data streams are symbol mapped and modulated to provide a pair of optical signals. The pair of optical signals are orthogonally polarized, and multiplexed for transmission across an optical fiber. A receiver circuit receives the transmitted signal and extracts the interleaved data streams. The interleaved data streams are de-interleaved to generate the original data streams. While the data streams can be interleaved and transmitted via a single wavelength optical signal, the data streams can be interleaved and transmitted over two or more different wavelength optical signals to further mitigate the effects of polarization distortions.

Abstract: The invention concerns a device for temporal subsampling of an OTDM optical signal at a predetermined subsampling frequency, comprising a generator (10) for generating clock pulses transmitted at the predetermined subsampling frequency and at a conversion wavelength ?H and a wavelength converter device (16) adapted to receive at its input the OTDM optical signal and the clock pulses in order to deliver at its output a subsampled OTDM optical signal at the conversion wavelength. The converter device comprises a linear optical amplifier (18) adapted to receive the OTDM optical signal and the clock pulses propagating in the opposite direction, the maximum linear power of the conversion being adjusted so that it can be less than the peak power of the OTDM optical signal, and a converter (20) of phase modulation into amplitude modulation.

Abstract: According to the invention, a very narrow-band transfer signal (LS) is generated by serially connecting a frequency modulator (2) and an amplitude modulator (4). The frequency modulator (2) is operated at a modulation index which at least largely suppresses the carrier signal (TS) while the amplitude modulator (4) suppresses the broadband portion of the spectrum by fading out the transfer signal (LS) during frequency-shift keying.

Abstract: Problem An object of the present invention is to provide an optical code division multiple access system which is used by many people. Means for Solving The above problem is solved by an optical code division multiple access, OCDMA, system 5 which have a central office 2 comprising a multi-port optical encoder 1, a decode part 4 comprising a decoder 3 for decoding optical code signals from the multi-port optical encoder 1. The multi-port optical encoder 1 transform input optical signals into optical code signals the wavelength of them differs at predetermined amount based on code pattern. The decoder 3 is super structured fiber Bragg grating, SSFBG, which has center wavelength that corresponds to optical code signal.

Abstract: An optical access network system capable of transmitting and receiving high-speed signals and which allows the number of subscribers to be increased without increasing the number of wavelengths used is provided. An optical line terminal and an optical network unit are joined via an optical fiber transmitting line, a star coupler, and a plurality of branching optical fiber transmitting lines. The optical line terminal and optical network unit are constituted comprising an optical processing section and an electrical processing section. The optical processing section comprises a light-emitting element and a light-receiving element.