Abstract: Channels in an optical network that carry optical signals are evaluated using signal characteristics and suitable channels are compared to identify the channels that represent a single conversation using matching criteria. In another aspect, only channels that carry optical signals representing conversations of interest are compared.

Abstract: A technique to identify a response cell in a ranging grant procedure is disclosed herein. The format of the response cell reduces the probability of erroneous response cell detection. The response cell is a conventional ATM cell whose payload includes multiple cell delineation bytes (CDBs).

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit via a working optical fiber, (2) a protection OSU of a protection circuit via a protection optical fiber, and (3) one or more optical network terminals (ONTs), where the protection OSU has a protection burst mode receiver (BMR) configured to receive an upstream optical signal from the optical splitter. The algorithm determines whether the protection OSU is functioning improperly. A reset pulse is applied at the protection BMR at a particular timing position and an attempt is made to interpret the current upstream cell received at the protection BMR. This process is repeated using different timing positions for the BMR reset pulse until the current upstream cell is correctly interpreted, e.g., based on the correct identification of an ATM header error correction (HEC) byte in the upstream cell.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit, (2) a protection OSU of a protection circuit, and (3) one or more optical network terminals (ONTs), where an ONT has (i) a working line termination (LT) unit of the working circuit and connected to the optical splitter via a working optical fiber and (ii) a protection LT unit of the protection circuit and connected to the optical splitter via a protection optical fiber. The present invention enables fast protection switching from the working circuit to the protection circuit. The arrival times of corresponding downstream cells are measured at both the working and protection LT units of the ONT, and information related to the arrival times is transmitted from the ONT to the protection OSU.

Abstract: An optical communication system wherein a light emission circuit operates with reduced power consumption. The optical communication system is used in a communication network wherein communication is had between a control node and plural controlled nodes using light rays amplitude-modulated with carrier modulation signals over 6 MHz. The control node transmits a transmission permission signal to each controlled node, which starts or interrupts light emission with desired transient characteristics by having reference to the transmission permission signal. For example, the amplitude of the infrared light rays is increased or decreased over e.g., a period as indicated at I1.

Abstract: A communications network (e.g. fibre to the home (FTTH) or wireless) comprises a head end, to which outstations are couples via a shared point-to-multipoint medium. The head end is arranged to transmit downstream to the outstations a sequence of frames comprising data frames and command frames. The command frames marshal control of upstream transmissions from the outstations. A first downstream command frame directed to a specific outstation indicates the beginning of a timeslot, and also indicates the time slot duration (including an indefinite duration). Where the duration is indefinite, a second command frame directed to at least the same outstation indicates the end of the allotted time slot. Further methods are provided to optimise timeslot allocation, and to support addition and removal of outstations on the network.

Abstract: A multi-layer photonic network and nodes used therein are provided. The multi-layer photonic network comprises a packet network which performs switching and transfer in packet units, and a photonic network comprising optical transmission lines and photonic switches, and which accommodates the packet network. The multi-layer photonic network also has a two layer structure of optical wavelength links (O-LSPs) and packet links (E-LSPs). The O-LSPs are constituted by the optical transmission lines and comprise optical wavelength switching capability (LSC) which is capable of switching in optical wavelength units and packet switching capability (PSC) which is capable of switching in packet units at both their ends. The E-LSPs include the O-LSPs and PSCs at both their ends. Each node includes a section for automatically establishing an O-LSP according to an establishment request for an E-LSP while taking account of path information including path cost, resource consumption, and traffic quantity.

Abstract: A method of transmitting data signals via an optical fiber between two network elements (14, 36, 43, 56) in a digital data transmission network comprises using a transmission protocol, wherein, in addition to said data signals, first control and/or monitor signals in the form of overhead signals are transmitted. An optical fiber amplifier (23) is inserted in the optical fiber between the two network elements. Additionally, second control and/or monitor signals in a format corresponding to said overhead signals are transferred between the optical fiber amplifier and at least one of the two network elements. An amplifier unit (22, 48) comprising an optical fiber amplifier (23) is adapted to be inserted in an optical fiber for the transmission of data signals between two network elements (14, 36, 43, 56) in such a data transmission network.