49 results about "Wavelength-division multiple access" patented technology

Optical fiber-based distributed communications components and systems employing wavelength division multiplexing (WDM) for enhanced upgradability. The system comprises a plurality of downlink optical transmitters configured to receive downlink electrical radio frequency (RF) signals from a plurality of RF sources and convert the downlink electrical RF signals into downlink optical RF signals. The system also has a wavelength division multiplexer configured to multiplex downlink optical RF signals into a plurality of downlink wavelengths over a common downlink optical fiber connected to a plurality of remote antenna units (RAUs). In this manner, additional downlink optical fibers are not required to support providing additional RAUs in the system. Wavelength-division de-multiplexing can avoid providing additional uplink optical fibers to distribute uplink signals to RAUs added in the system.

The present invention provides an optical wavelength-division multiple access system and a corresponding optical network unit. A wavelength band Da (wavelengths λd1 to λdn) for downlink optical signals corresponding to the n ONUs, a wavelength band Ua (wavelengths λu1 to λun) for uplink optical signals corresponding to the n ONUs, a wavelength band Db (wavelengths λdn+1 to λdn+m) for downlink optical signals corresponding to the m ONUs, and a wavelength band Ub (wavelengths λun+1 to λun+m) for uplink optical signals corresponding to the m ONUs are set different from one another, the wavelength bands Ua and Ub are set adjacent to each other, and the wavelength bands Ua and Da or the wavelength bands Ub and Db are set adjacent to each other. Each of the ONUs has downlink optical signal receiving unit for receiving a downlink optical signal of one of the wavelengths λd1 to λdn+m in the wavelength bands Da and Db which wavelength is assigned to the ONU, and uplink optical signal receiving unit for receiving an uplink optical signal of one of the wavelengths λu1 to λun+m in the wavelength bands Ua and Ub which wavelength is assigned to the ONU or an uplink optical signal within a broad band including the wavelength bands Ua and Ub.

Provided are a wavelength division multiplexing-passive optical network (WDM-PON) in which a reflective semi-conductor optical amplifier (RSOA) is used as each optical transmitter of an optical line termination (OLT) and an optical network unit (ONU) and additional spectrum-sliced light is injected into RSOAs of each of the OLT and the ONU, and a WDM-PON that is combined with time division multiple access (TDMA) technology, by which the number of included ONUs increases and conventional TDMA ONUs can be used.

Provided is an Optical Line Terminal (OLT). The OLT may include a first Wavelength division multiplexer / demultiplexer (WDM MUX / DeMUX) to perform a wavelength demultiplexing on seed light received from a seed light source, and a second Wavelength division demultiplexer (WDM DeMUX) to receive, from at least one ONU / ONT, an upstream optical signal generated using the seed light having the wavelength demultiplexing performed, and to perform a wavelength multiplexing on the received upstream optical signal.

Provided is a time division multiplex (TDM) / wavelength division multiple access (WDMA) passive optical network (PON) device. The TDM / WDMA PON device comprises a base station terminal, a wavelength splitter, and a subscriber terminal optical transceiver. The base station terminal comprises a transmitter time-division-multiplexing and simultaneously modulating and outputting a plurality of different wavelength optical signals, an optical circulator transmitting the optical signals output from the transmitter to an optical distribution network and transmitting optical signals received from the optical distribution network to a receiver and the receiver demultiplexing wavelength division multiplexed upstream signals from the optical distribution network through the optical circulator, converting the demultiplexed upstream signals into a plurality of electrical signals, and delivering the electrical signals to an upper layer. The wavelength splitter splits the downstream signals from the base station terminal to subscriber ports corresponding to wavelengths and multiplexes the optical signals received from each of the subscriber ports to the base station terminal. The subscriber terminal-optical transceiver receives the downstream signals from the wavelength splitter and reuses the received downstream signals as optical sources for upstream signals.

The invention discloses a base band migration system for wireless fronthaul of a passive optical network. The system comprises a base band processing unit (BBU), radio remote units (RRU) and the passive optical network, wherein the passive optical network is a passive optical fiber net (TWDM-PON) based on time and wavelength division multiplexing, the base band wavelength of the passive optical network is migratory, the BBU is arranged in a central apparatus room and used for processing base band signals and sending the signals to the RRUs of each remote node through the TWDM-PON, the RRUs convert the signals into electric radio frequency signals which are then amplified and output, and the BBU and the RRUs are separated. The base band migration system is low in cost, high in speed, efficiency, power budget and capacity, and large in transmission distance.

The present invention proposes a wavelength division multiplexing-passive optical network (WDM-PON) system which transmits downstream data to an optical network unit (ONU) as an optical line termination (OLT) receives seed light from a spectrum-sliced external light source module. One characteristic of the proposed WDM-PON system is that optical transmitters of the OLT and ONU are operated regardless of optical wavelength. Another characteristic of the proposed WDM-PON system is that a conventional TDMA-PON (E-PON or G-PON) ONU can be accommodated without a change.

The invention discloses a method and a device for protecting trunk fibers of a wavelength division multiplex (WDM) passive optical network (PON). The method is applied to an optical line terminal (OLT) side of a WDM PON comprising at least two trunk fibers; and an OLT comprises at least two physical interfaces which are respectively connected with the corresponding trunk fibers in the WDM PON to form a trunk fiber link. The method comprises the following steps: detecting whether a first trunk fiber link connected with a first physical interface fails or not; and switching from the first trunkfiber link to a second trunk fiber link connected with a second physical interface if the first physical interface fails.

The invention discloses a passive optical network system based on Nyquist wavelength division multiplexing and a realization method. The system comprises an OLT (optical line terminal) and N ONUs(optical network unit), wherein the OLT is provided with a multi-carrier generation device and one three-port optical circulator; the multi-carrier generation device generates N paths of optical carriers with an equal frequency interval; N paths of downlink Nyquist wavelength division multiplexing signals are sent to the ONUs via a downlink feed line optical fiber; the three-port optical circulator transmits the N paths of optical carriers to the ONUs via an uplink feed line optical fiber for uplink modulation; and an uplink Nyquist wavelength division multiplexing signal from the ONUs is transmitted to the OLT via the uplink feed line optical fiber. According to the passive optical network system and the realization method., uplink and downlink both adopt the Nyquist wavelength division multiplexing technology, the advantage of WDM-PON (wavelength division multiplexing-passive optical network) is kept, the servable user amount is greatly increased by utilizing the high spectrum efficiency of the WDM-PON, and realization is simple.

A network system of light without light source based on the wavelength division multiplexing technique includes a plurality of optical line terminals which adopt uplink wavelength and downlink wavelength that are mutually independent, a wavelength division multiplexing / demultiplexer connected with the plurality of optical line terminals, a wavelength division multiplexing multiplexer connected with the wavelength division multiplexing / demultiplexer by optical fiber, and a plurality of optical splitters which adopt the same uplink wavelength and the same downlink wavelength corresponding to the optical line terminals and are connected with the wavelength division multiplexing multiplexer. A plurality of optical network units optically connected with the optical splitters. The invention realizes optical fibre communication among a plurality of optical line terminals and a plurality of optical network units through a single optical fibre, thus saving the optical fibre resources for the connecting section between an MAN and a district and reducing the cost of optical fibre access. When the network bandwidth is updating, alteration on the updating of the network bandwidth can be realized only by increasing the qualities of the accessed optical network line terminals and corresponding optical splitters, thus greatly reducing the alteration cost.

The invention relates to a WDM-PON (wavelength division multiplexing-passive optical network) for performing OTDR (optical time domain reflectometry) test without influencing service, and the system comprises an OLT (optical line terminal) and ONU (optical network unit), which are connected with each other through an optical fiber distribution network circuit, a waveband C defined in DWDM (dense wavelength division multiplexing) is bi-directionally adopted between the OLT and the ONU as a working wavelength band, OTDR adopts a wave band L defined in DWDM as a working wavelength band, an AWG (arrayed waveguide grating) in the optical fiber distribution network circuit is periodic and can work simultaneously in the waveband C and the waveband L; a C / L WDM device in the optical fiber distribution network circuit completes complexing and division of optical signals of two working wavelength bands in the WDM-PON system and the OTDRR. The WDM-PON system for performing the OTDR test without influencing the service is simple and feasible, low in cost, high in reliability and easy to popularize. Due to the adoption of the WDM-PON system, the OTDR test can be conducted by a passive optical network system under the condition that the user service is not interrupted, and the OTDR reflected optical signal of each branch distribution optical fiber is free from being overlapped on time domain at the receiving moment of OTDR in the OTDR test.

The present invention discloses a hybrid optical amplifier coupling a Raman fiber amplifier and a semiconductor optical amplifier, comprising: a laser diode generating and radiating a laser light for a Raman optical amplification; a wavelength division multiplexer passing an incident signal light and radiating a laser light radiated from the laser diode in a reverse direction of the incident signal light; and a gain clamped semiconductor optical amplifier amplifying an optical signal light radiated from the wavelength division multiplexer.

The invention discloses a passive optical network based on Wave Division Multiple Access Ethernet and its transmitting data method. As for physical structure, the network is a topological structure from one point to multi-point; as for logical channels of transmitting data, the network applies a topological structure with Wave Division Multiple Access from one point to one point in the up direction. The transmitting data method of the network: in the down direction, the data signals processed by OLT are emitted in order from the same transmitting port, on reaching ODN, they will be broadcasted by means of optical power division, every optical network unit only selects the data given to itself; in the up direction, the data of every optical network unit are emitted which load different independent wavelength, on reaching ODN, the light waves are merged, then the up data corresponding to every optical network unit are respectively selected after every wavelength are demultiplexed in OLT, the processed data are carried to the Wide Area Network or retransmitted to the other optical network unit. The invention can simplify system design and make the rate of transmitting data high.

Provided are a wavelength conversion apparatus in a Time Division Multiplexing Passive Optical Network (TDM-PON) system based on a Wavelength Division Multiplexing (WDM) system, and an optical transmission method using the wavelength conversion apparatus. Each subscriber does not need to have its own wavelength but transmits an uplink signal using a wavelength band used in the TDM-PON system and routs optical network unit (ONU) uplink signals belonging to the same ONU to a wavelength conversion apparatus positioned in a subscriber area. The wavelength conversion apparatus converts the ONU uplink signals into wavelengths and uplinks the wavelengths of an optical line terminal (OLT) of a central office (CO) so as to enable a WDM transmission. Thus, a method of constituting a wavelength conversion apparatus and a remote node (RN) using the wavelength conversion apparatus can be suggested to realize a hybrid-PON system into which TDM-PON system and WDM systems are combined. In the hybrid-PON system, an ONU uses a wavelength used in the TDM-PON system and requires a lower optical power than an ONU of the TDM-PON system. Therefore, the WDM system can be easily applied in an area in which the TDM-PON system is installed.

The invention relates to the field of optical fiber communication, in particular to a method for acquiring wavelength values by remote equipment in a wavelength division multiplex-Ethernet passive optical network (WDM-EPON) passive optical network system. The key points of the method comprise that: the wavelength values of an optical network unit (ONU) uplink sending signal are filled in 31 byte filling domains between the 'synchronous time' field and the 'frame check sequence' field in a discovery message frame in IEEE802.3ah; and ONU transmits the message to an optical line terminal (OLT) according to the wavelength values of the ONU uplink sending signal filled in 31 byte filling domains. The method can correctly allocate the wavelength values of the uplink sending signal to the ONU which is not discovered by the OLT in the WDM-EPON mixed passive optical network system, so that the ONU can be registered successfully.

The embodiment of the invention discloses an optical access system comprising one or more optical add-drop multiplexers sequentially connected through optical fibers in series to form a wavelength division multiplexing ring, wherein both ends of the wavelength division multiplexing ring are connected with one optical line terminal. The optical line terminal comprises a transmitter array, a multiplexer, a wavelength division ring protector, a receiver array and a demultiplexer, wherein the wavelength division ring protector is used for detecting whether the wavelength division multiplexing ring is broken or not; when the wavelength division multiplexing ring is normal, multiplexed downstream optical signals are transmitted to the wavelength division multiplexing ring from one end; when the wavelength division multiplexing ring is broken, the downstream optical signals are transmitted to the wavelength division multiplexing ring from both ends; and when the wavelength division multiplexing ring is normal, upstream optical signals are received from one end of the wavelength division multiplexing ring, and when the wavelength division multiplexing ring is broken, the upstream optical signals are received from both ends of the wavelength division multiplexing ring, and then the received upstream optical signals are transmitted to the demultiplexer.

The present invention provides a wavelength division multiplexing passive optical network transmission system based on optical orthogonal frequency division multiple access, including an optical line terminal, a ring access fiber, and several sub-passive optical networks. The remote nodes of the network are respectively connected to N optical network units through corresponding distributed optical fibers. Multiplexed signals, WDM signals are demultiplexed at the remote node, then transmitted to the corresponding sub-passive network, and the information is transmitted to each optical network in the corresponding sub-passive optical network through the corresponding distributed optical fiber network unit. The present invention realizes large-capacity, long-distance communication, can make full use of the advantages of OFDM technology, and improves frequency band utilization. In addition, the ring tree topology can realize the integration of metropolitan area network and access network, and improve The reliability of the network, thereby improving the access capability and service quality of the passive optical network.

An optical signal processing method, optical module, OLT optical signal processing method and OLT are disclosed in the embodiments of the present invention. The optical module comprises two photoelectric transceiver units and a wavelength division multiplexer unit. The photoelectric transceiver units are configured to: generate, according to an electric signal, a downlink optical signal with a corresponding rate and wavelength, and then output the downlink optical signal to the wavelength division multiplexer unit; and receive an uplink optical signal with a rate and wavelength corresponding to a burst mode from the wavelength division multiplexer unit, and convert the uplink optical signal into an electric signal. The wavelength division multiplexer unit is configured to: after receiving the downlink optical signals from the two photoelectric transceiver units, wavelength division multiplex the downlink optical signals and then output the outcome; receive the uplink optical signal, de-multiplex the uplink optical signal to obtain uplink optical signals with different rates and wavelengths, and output the uplink optical signals to the corresponding photoelectric transceiver units respectively.

Provided are a wavelength division multiple access (WDMA) central station, a WDMA user interface, and an optical layer connection service method in an optical network using a WDMA scheme. The WDMA central station for an optical layer connection service in an optical network using a WDMA scheme, includes: a WDMA connection unit for receiving optical signals transmitted from a plurality of WDMA user interfaces, distributing and selecting the optical signals, and transmitting the distributed and selected optical signals to a plurality of user stations; and a network controller unit for transceiving control information related to optical layer connection and network status information received from the plurality of WDMA user interfaces through the WDMA connection unit, wherein an optical layer connection service is provided according to request quality of the plurality of user stations.

The invention discloses a digital array radar optical fiber transmission network and a control method thereof, the optical fiber transmission network comprises a wavelength division multiplexing / demultiplexing unit and a 1: M power divider, wherein the wavelength division multiplexing / demultiplexing unit is connected with a processor through a single-mode optical fiber and is connected with each sub-array in an array surface through the single-mode optical fiber, the 1: M power divider is connected with the wavelength division multiplexing / demultiplexing unit through a single-mode optical fiber and is connected with each sub-array in the array surface through the single-mode optical fiber, M is the number of the sub-arrays in the array surface, and each sub-array is composed of a pluralityof T / R module sub-array units. According to the invention, based on the WDM technology and the PON technology, the transmission of downlink digital signals, downlink analog signals and uplink digitalsignals are supported, a time division multiplexing mechanism is adopted for the uplink digital signals, so that the competition phenomenon when the sub-arrays send data to the process is avoided; and a broadcasting mechanism is adopted for the downlink analog and digital signals so as guaranteed that all subarray units receive the same data.

The invention provides an optical line terminal and an optical network unit. The optical line terminal comprises a wavelength division multiplexing element, a coarse wavelength division multiplexer, an optical coupler, an uplink multi-channel receiver, a downlink multi-channel transmitter and a wavelength shift monitoring unit; the wavelength division multiplexing element is used for multiplexing and demultiplexing uplink optical signals and downlink optical signals; the coarse wavelength division multiplexer is used for filtering and demultiplexing the uplink optical signals; the optical coupler is used for dividing the filtered and demultiplexed uplink optical signals into a first channel of uplink optical signals and a second channel of uplink optical signals; the uplink multi-channel receiver is used for receiving the first channel of uplink optical signals; the downlink multi-channel transmitter transmits the downlink optical signals via an arrayed waveguide grating and the wavelength division multiplexing element; the wavelength shift monitoring unit is used for detecting whether the wavelength of the second channel of uplink optical signals exceeds a boundary threshold, and when the wavelength of the second channel of uplink optical signals exceeds the boundary threshold, optical network units which need to adjust uplink wavelength are determined and indication information is included into the downlink optical signals of the downlink multi-channel transmitter.

A method and apparatus for a wavelength division multiplexing (WDM) optical transmission system wherein the optical transmission system has an optical signal transmitter which functions as a passive hub, in which only optical signal processing is performed, while associated electronic signal processing is performed outside the passive hub. The passive hub includes upconverter devices that place the optical signal bands at frequencies that allow separation of the bands at a detector. The detectors are thus loaded with more than one wavelength at a time. The optical transmission signals are optically combined and / or amplified onto a single fiber that is fed to a headend device, where the wavelengths of the optical transmission signals are demultiplexed and fed to the receivers.

Provided is a time division multiple access over wavelength division multiplexed passive optical network (TDM-over-WDM-PON) system. According to the TDM-over-WDM-PON system, a downstream optical signal is separated according to a wavelength in a remote node, transmitted to an optical amplifying device located in subscriber equipment, amplified in the optical amplifying device, transmitted back to the remote node, and then transmitted to the subscriber equipment. Also, an upstream optical signal is transmitted to a wavelength converting device located in the subscriber equipment from the remote node, wavelength-converted in the wavelength converting device, returned back to the remote node, and then transmitted to a central office.

The invention is applicable to the field of optical communications, and provides a method for improving the accuracy of an OSNR (Optical Signal to Noise Ratio) of a wavelength division multiplexing system. On an application occasion of the wavelength division multiplexing system, particularly on an application occasion of a system having a small number of channels, less than 10 channels, by testing signal optical power and noise optical power of a tested channel at the output end of a Raman fiber amplifier or an erbium-doped fiber amplifier at a system receiving end, by adopting a noise function and a correction factor, an OSNR of each channel of the wavelength division multiplexing system is acquired according to the measured signal optical power and noise optical power. By the adoption of the method, the OSNR of each channel of the wavelength division multiplexing system can be accurately extracted, and a test error can be reduced, so that the reliability and the stability of the wavelength division multiplexing system are effectively improved.

The invention discloses a wavelength division multiplexing bidirectional transmission system based on a delayed optical feedback chaotic semiconductor laser. The system comprises a first reflector, afirst semiconductor laser, a first wave separator, a first optical chaotic signal link, a first wavelength division multiplexer, a first optical fiber, a second wavelength division multiplexer and a second optical chaotic signal link which are sequentially connected, wherein the second optical chaotic signal link is connected with the first wave separator, the first optical chaotic signal link andthe second optical chaotic signal link are used for transmitting optical chaotic signals, any one of the first optical chaotic signal link and the second optical chaotic signal link comprises a sending end, and the other one comprises a receiving end; and the first wavelength division multiplexer or the second wavelength division multiplexer is used for coupling an optical chaotic signal or re-dividing the optical chaotic signal into different wavelength chaotic signals. The system solves the problems of information confidentiality and long-distance large-capacity communication in the chaoticcommunication process.

The invention discloses a bidirectional optical amplification device based on wavelength division multiplexing transmission. The bidirectional optical amplification device comprises a bidirectional wavelength division multiplexing unit and a unidirectional optical amplifier; the bidirectional wavelength division multiplexing unit is used for carrying out wavelength division multiplexing on opticalsignals from the port A and the port B on an optical fiber and sending the optical signals to the unidirectional optical amplifier for amplification, and then separating the amplified optical signals, so that the signals input by the port A are amplified by the one-way optical amplifier and then output to the port B, and the signals input by the port B are amplified by the one-way optical amplifier and then output to the port A. According to the invention, optical amplification is carried out on the bidirectional time / frequency signal based on the wavelength division multiplexing transmissiontechnology, the influence of multiple amplification of Rayleigh scattering and other noises on the performance of the optical fiber time / frequency transmission signal can be effectively avoided, andthe amplification of the unidirectional communication service transmission signal in the optical fiber link is not influenced. The bidirectional optical amplification device can be used for an opticalfiber time, optical fiber frequency and optical fiber time frequency combined transmission system, and can also be used for a transmission system combined with one-way communication transmission service.

The invention relates to a wavelength division multiple access ultra-wideband multiuser detection method based on Gaussian mixture model clustering, relates to a wavelength division multiple access ultra-wideband multiuser detection method and aims to solve problem of poor real-time performance and low detection performance of a WDM ultra-wideband multi-user detection method in the prior art. Themethod comprises steps that S1, a WDM ultra-wideband signal under a Gaussian channel is obtained, the ultra-wideband signal is inputted into K matched filters for preliminary detection to obtain the matched filtering result y; S2, the matched filtering result y of K users is subjected to symbol decision and code element mapping, the matched filtering result y is mapped to be the code element mapping result conforming to a Gaussian mixture model; and S3, the code element mapping result phi(b<^>j) is subjected to Gaussian mixture model clustering, after an error code element is corrected, the WDM ultra-wideband multi-user detection result is outputted. The method is applied to the ultra-wideband communication field.