Abstract: Disclosed is a secure/non-secure bypass switch, including at least one input port for receiving signals; a control module for determining if a secure or a non-secure operating mode is selected; if a non-secure mode is selected, configuring at least one relay to route the signals through at least two fiber optic modems; and if a secure mode is selected, configuring the at least one relay to route the signals through an encryption device.

Abstract: A system that facilitates optical multiplexing and demultiplexing. The system includes an optical transmitter which is structured in the following way. A wavelength-splitting mechanism is coupled to the optical transmitter, which separates the wavelengths of light onto an array of input-optical-waveguide busses within the optical transmitter. An array of ring modulators within the optical transmitter is coupled to each optical-waveguide bus, wherein the input-end of a given ring modulator is coupled to a corresponding input-optical-waveguide bus. Output-optical-waveguide busses within the optical transmitter are coupled to the array of ring modulators, wherein the output-end of each ring modulator is coupled to a corresponding output-optical-waveguide bus. When a modulation signal is applied to a given ring modulator within the array of ring modulators, a specific wavelength of light is directed to the corresponding output-optical-waveguide bus.

Abstract: The invention relates to an optical transmission system which allows high quality transmission of signal light, and has a configuration that is suitable particularly for CWDM optical transmission. In the optical transmission system, signal channels outputted from non-temperature controlled direct modulation light sources are multiplexed by a multiplexer, transmitted through an optical fiber transmission line, and demultiplexed into a first wavelength band ?1 and second wavelength band ?2 by a demultiplexer. The signal channel group in the second wavelength band ?2 of which the absolute value of chromatic dispersion is large is dispersion-compensated for by a non-temperature controlled dispersion compensator. The chromatic dispersion of the signal channels in the second wavelength band ?2 after passing through the dispersion compensator is set to be negative over a temperature range of 0° C. to 60° C.

Abstract: The aim of the invention, which concerns a method and a system for converting an optical received pulse train into an electrical output pulse train, is to create a method and an associated circuit arrangement for converting an optical received pulse train into an electrical output pulse train whereby achieving an improvement in transmission quality and a reduction in latency time.

Abstract: The switching system comprises a routing device having selection modules each having one input and a plurality of outputs adapted to switch spectral channels received selectively to respective outputs as a function of a command. The routing device comprises a first stage comprising a plurality of modules whose inputs constitute the input ports of the device, a second stage comprising at least one first selection module whose outputs constitute the output ports of the device, and an intermediate stage for coupling the input of the first selection module of the second stage both to a first output of a first selection module of the first stage and to a first output of a second selection module of the first stage. The switching system applies to interconnection panels in switching nodes for optical networks.

Abstract: A fiber optic protection apparatus includes a first optical switch, a first fault detection device, and first switch control device. The first optical switch is placed at the reception node of an optical link and has a primary input port connected to a primary optical transmission path. A secondary input port is connected to one secondary optical transmission path. The first fault detection device is in communication with the primary optical transmission path to identify a fault within the primary optical transmission path and to generate a fault signal indicating type or location of the fault. The fault signal is transferred to the first switch control device that is in communication with the optical switch. This causes the optical switch to connect one of the secondary optical transmission paths to the reception node when the fault signal indicates that the primary optical transmission path has a fault.

Abstract: A transponder unit which relays signals between a plurality of channels of an optical transport network and a plurality of clients. The interconnections within the transponder unit are reconfigurable for selective connections. A connection between a first client and a first network channel and a connection between a second client and a second network channel is independent of each other and may be selected so that the second client is connected to the first network channel and the first client is connected to the second network channel. Other selected connections are also possible.

Abstract: Disclosed is a secure/non-secure bypass switch, comprising a first port for receiving input signals; a first relay having an input, a first output and a second output, said input connected to said first port, and said second output connected to a second port; a first fiber optic modem having an input and an output, said input connected to said first output of said first relay; a second fiber optic modem having an input and an output, said input connected to said output of said first fiber optic modem; and a second relay having an output, a first input and a second input, said first input connected to said output of said second fiber optic modem, said second input connected to a third port, and said output connected to a fourth port.

Abstract: Disclosed is a wavelength division multiplexing (WDM) optical transmission system including: an optical transmitter for transmitting, to an optical fiber transmission path, a WDM signal obtained by multiplexing a plurality of optical signals on the optical fiber transmission path in terms of wavelength, the plurality of optical signals respectively having negative chirps; an optical receiver for receiving the WDM signal from the optical fiber transmission path; and at least one relay node which is provided between the optical transmitter and the optical receiver. Each of the relay node and the optical receiver includes a dispersion compensator for compensating a chromatic dispersion suffered in the optical fiber in the immediately preceding transmission span. Moreover, a dispersion adder for beforehand adding a predetermined positive dispersion amount to the WDM signal before transmission is included in the optical transmitter or at least one relay node.

Abstract: In the WDM communication system, in the absence of data to be transmitted on an optical channel, a pilot signal transmitting means transmits the channel-unique pilot signal data on the channel. A WDM communication apparatus on a receiving end detects the pilot signal data in the received WDM signals, and on the basis of the detection result, it evaluates whether each channel is used or not. It is thus easy to recognize which channel is unused (idle) of the WDM signals, so that channel resources can be used effectively according to the traffic.

Abstract: A method and apparatus for fault notification in an optical network are described herein. In one embodiment, an exemplary process includes detecting at a node that at least a portion of a first unidirectional path of an optical circuit is down, where the first unidirectional path is originated from a first terminating node. In response to the detection, the node signals the first terminating node by removing at least a portion of light of a second unidirectional path in an opposite direction of the first unidirectional path of the optical circuit, to indicate a path between the node and the first terminating node is down. Other methods and apparatuses are also described.

Abstract: An optical transmission system comprises an electrical source and an electrical-to-optical converter. The electrical source is adapted to provide an electrical signal at an output thereof. The electrical-to-optical converter has an input coupled to the output of the electrical source and is operative to convert the electrical signal to a corresponding output optical signal. The electrical source comprises a pre-emphasis circuit or other electrical signal equalization circuitry configurable to control a waveform of the electrical signal so as to produce a desired level of jitter in the output optical signal.

Abstract: Reroutable protection schemes of an optical network are described herein. In one embodiment, an access node detects that at least a portion of a first path of an optical circuit fails based on a loss of a light of the at least a portion of the first path. In response to the detection, the access node provisions a second path leading to a destination node of the first path without waiting for an update of a routing database regarding the failure of the first path, where the second path satisfies a set of disjointness requirements with respect to the first path. Other methods and apparatuses are also described.

Abstract: A passive optical arrangement for indicating the presence of a change in ownership along a fiber optic cable span uses an attenuation unit at a splice location that will severely attenuate an optical signal propagating along the span at a predetermined “marker” wavelength. Particularly well-suited in combination with determining the physical location of a fault along a fiber optic cable, the arrangement allows a technician to use an OTDR at the marker wavelength to determine both the physical location of the fault as well as the physical location of a change in ownership (if any) between the technician and the fault location, since the presence of the attenuation unit will register as a large step-wise change in signal propagation.

Abstract: The present invention allows remote antenna units for radio frequency signal transmission and receipt to operate without the requirement for remote electrical power supplies or for connecting cables that incorporate electrical conductors. According to an aspect of the present invention, an optical communications system employing radio frequency signals comprises a central unit; at least one remote unit having at least one optoelectronic transducer for converting optical data signals to radio frequency signals and converting radio signals to optical signals and at least one antenna to receive and send radio frequency signals; at least one optical fiber data link between the central unit and the remote unit for transmitting optical data signals therebetween; and at least one optical fiber power link between the central unit and the remote unit for providing electrical power at the remote unit.

Abstract: A land-based cable station is provided for interfacing with first and second undersea transmission segments of an undersea optical transmission system. At least one first bypass optical transmission path is provided for selectively coupling reflectometry probe signals and backscattered and reflected signals located at a prescribed wavelength from a first interface device to a second interface device. At least one second bypass optical transmission path is provided for selectively coupling reflectometry probe signals and backscattered and reflected signals located at a prescribed wavelength from the second interface device to the first interface.

Abstract: A mirror controller of an optical switch comprises a signal generator (10, 82, 83) for passing the optical signal on the same light path as the one for optical communication using the optical switch, and an image analyzer (15, 16, 81) detecting the optical signal as the light scattered by at least one of tilt mirrors (111, 123) and an output collimator array (14). The image analyzer detects the position of the light beam image as a control position (121, 141, 85) based on the scattered light, and controls the tilt mirrors in such a manner that the detected control position coincides with the predetermined desired target position (122, 142, 84, 86) on at least one of the tilt mirrors and the output collimator array. The mirror controller can realize the connection test of the optical signal between input and output with high accuracy and reliability.

Abstract: The invention relates to optoelectronic modules for generating and/or receiving optical signals for use in fiber-optic communication systems, such as optical transponders or transceivers, having a reconfigurable control and status (C&S) interface with a host device. The optoelectronic module includes an electrical multi-pin host connector having a plurality of pins for communicating a plurality of digital C&S signals between the host and the module, functional hardware responsive to the digital control signals and comprising sensing means for generating digital status signals, and processing means formed by an FPGA and a processor for processing the digital C&S signals.

Abstract: A free-space adaptive optical laser communication system having signal transmission and reception channels at all terminals in the communication system, wherein wavefront sensing (WFS) and wavefront correction mechanisms are employed along signal transmission and reception channels of all terminals in the communication system (i.e. adaptive optics) to improve the condition of the laser beam at the receiver (i.e. reduce the size of the spot a the detector plane). in the illustrative embodiment, the WFS mechanisms employ a novel WFS control process, in which active updating of reference positions and subaperture locations on the wavefront sensor. These WFS mechanism can be used in diverse application environments, including but not limited to FSO laser communication systems.

Abstract: A wide-coverage high-capacity network that scales to multiples of petabits per second is disclosed. The network comprises numerous universal edge nodes interconnected by numerous disjoint optical core connectors of moderate sizes so that a route set for any edge-node-pair includes routes each of which has a bounded number of hops. A core connector can be a passive connector, such as an AWG (arrayed wave-guide grating) device, or an active connector such as an optical channel switch or an optical time-shared channel switch. The core capacity is shared. Thus, failure of a proportion of core connectors reduces network connectivity but does not result in a major service discontinuity. The network uses a source routing scheme where a set of candidate routes for each node pair is determined from the network topology and the candidate routes for a node pair are sorted according to their differential propagation delays. A method of measuring the differential propagation delay is also disclosed.