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.

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 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.

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 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 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.