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: A system and a method for quantum key distribution over a multi-user wavelength division multiplexing (WDM) network are disclosed. The system comprises a tunable or multi-wavelength transmitter; a plurality of receivers, each assigned a receiving-wavelength; and a multi-user WDM network linking the transmitter to the receivers. The transmitter can select a receiver among the receivers to be communicated therewith and transmit quantum signals to the selected receiver over the WDM network. The quantum signals are at a wavelength equal to a receiving-wavelength of the receiver. Therefore the WDM network allows quantum signals to be communicated between the transmitter and the receivers by wavelength routing.

Abstract: An optical transmission device includes an input interface unit, a cross-connecting unit, and an output interface unit, and a bandwidth switching control unit, and switches bandwidths allocated to paths in a transmission channel that connects to an adjoining optical transmission device synchronously with the adjoining optical transmission device. When the bandwidths are not continuous in the transmission channel, the bandwidth switching control unit controls the input interface unit, the cross-connecting unit and the output interface unit to rearrange the non-continuous bandwidths into continuous ones.

Abstract: An optical signal, which is a low-speed signal superimposed on a high-speed phase modulated optical signal by intensity modulation, is used. In an optical receiver apparatus 40, a received signal is split, and one of the split signals is O/E converted and low frequency component alone is extracted via a filter 46. A clock is extracted from low-frequency component by CDR, and is compared with a preset frequency. Using the frequency difference obtained, dispersion compensation is performed with low accuracy. Next, the amount of phase control of the delay interferometer 21 is adjusted so that the amplitude of the electrical signal is maximized. An error rate is measured, and fine adjustment is performed to improve the error rate.

Abstract: The present invention is an optical pulse time spreading device comprising a plurality of optical pulse time spreaders that output an input optical pulse as a series of chip pulses stream that are sequentially arranged time-spread on a time axis in accordance with optical phase code. Each of the optical pulse time spreaders comprises phase control means that supplies a phase difference between adjacent chip pulses. Identification parameters are introduced to realize channel discrimination by changing the phase difference conditions supplied between adjacent chip pulses for each of the phase control means. The phase control means have a structure in which an SSFBG is fixed to the core of the optical fiber, for example. The SSFBG has unit FBGs that are arranged in series in the waveguide direction of the core. The code values of the optical phase code established for the phase control means correspond each one-on-one with each of the unit FBGs.

Abstract: A fiber optic cable topology for a fiber optic repeater distributed antenna system network and a method of configuring the network using the topology is disclosed. The topology includes a first base transceiver station hub, a second base transceiver station hub, and a fiber optic backbone coupled between the first base transceiver station hub and the second base transceiver station hub, where the fiber optic backbone includes a plurality of optical fibers. A distributed antenna system repeater node is coupled to the first base transceiver station hub and the second base transceiver station hub. An optical fiber of the plurality of optical fibers in the fiber optic backbone includes a first portion and a second portion, where the first portion extends between the first base transceiver station hub and the DAS repeater node and the second portion extends between the second base transceiver station hub and the DAS repeater node.

Abstract: An apparatus includes a time-domain wavelength-interleaved optical network that connects a plurality of edge nodes. Each of the edge nodes is configured to receive optical communications from others of the edge nodes on an associated wavelength-channel. The number of edge nodes is larger than the number of the wavelength-channels.

Abstract: Improved dispersion compensating circuits for optical transmission systems are disclosed. According to the improved method, there is provided a compensation circuit comprising a varactor diode network. The network is preferably inserted between a source of laser modulating signal and the laser. A low pass filter constructs the network. The network preferably includes an inductance and a combined circuit, which includes varactors. The network preferably provides an amplitude dependent delay of the modulating signal applied to the laser. In a first embodiment, a fixed capacitor is in series with a varactor and connected to a DC bias through inductor. In a second embodiment, second varactor is in series with varactor instead with an opposite polarity of a fixed capacitor as used in the first embodiment. In a third embodiment, two varactors 301 and 302 are used in place of the fixed capacitor in parallel.

Abstract: An optical transmit and receive circuit that includes a single control module that controls the transmit and receive operational behaviors in multiple transmit and receive data paths of the optical transmit and receive circuit. By having a single control module control operational behaviors of multiple electro-optic transducer drivers, and multiple post-amplifiers, the size of the overall combination may be reduced.

Abstract: An optical bi-directional transceiver module is disclosed. The optical bi-directional transceiver module is suitable for an optical transmission/reception operation on the condition that an interval between two wavelength bands such as C and L bands is very narrow. The transceiver module manufactures a stable optical-communication light source based on the injection-mode-locked FP LD, such that an improved light source capable of substituting for the conventional high-quality DFB laser can be implemented. As a result, the light source for the WDM-PON system can be manufactured. The optical bi-directional transceiver module can be manufactured even when the light signal having a narrow interval between two wavelength bands is used, resulting in reduction of costs, size, and power consumption of the light source.

Abstract: This application describes devices and techniques for dynamically controlling polarization light at one or more locations along the optical transmission path to reduce optical noise and PMD in the optical signal. One device according to an implementation includes a polarization controller to receive an optical signal and operable to control polarization of the optical signal in response to a control signal, a fixed optical polarizer to receive output from the optical polarization controller and to produce an output optical signal, and a circuit to receive a fraction of the output optical signal from the fixed optical polarizer and operable to produce the control signal in response to an output power level of the output optical signal which controls the polarization controller to maximize the output power level.

Abstract: A control device with a switchable bandwidth including: an integrating element with a first capacitance, which is charged and discharged by at least one current; at least one second capacitance, which can be connected in parallel with the first capacitance via a first switch; and at least one voltage follower, via which the voltage present at the first capacitance can be fed to the second capacitance. In this case, the first switch is open if the voltage present at the first capacitance is fed to the second capacitance by means of the voltage follower. The first switch is closed if the second capacitance is connected in parallel with the first capacitance. The invention enables a further capacitance to be supplementary connected without a disturbance signal arising.

Abstract: An optical phase difference control system is provided for controlling a phase difference of a single optical time-division multiplexed signal obtained by multiplexing a plurality of modulated optical signals encoded. The control system includes an interferometer and a low-frequency extractor. The interferometer is used for receiving part of the optical time-division multiplexed signal to split it into first and second signals, giving, between the first and second signals, a phase difference equivalent to one bit of the optical time-division multiplexed signal, and thereafter multiplexing the first and second signals. The low-frequency extractor is used for adding together signals, output from the interferometer, which have the similar intensity every two successive bits, and extracting a low-frequency waveform signal as a signal for controlling the phase difference of the single optical time-division multiplexed signal.

Abstract: The present invention provides a system and method for multi-rate, high-sensitivity CDR, including a variable/adjustable decision threshold, RF input clock recovery, and OE conversion feature. The system includes an optical input connector, CDR circuit, decision threshold circuit, internal power supply, OE converter, external electrical output, and multiple clock outputs. The system is assembled in a single, stand-alone unit. The system includes an OC-192 data output, and OC-192 (9.953-10.709 GHz) and ¼ OC-48 (2.488-2.677 GHz) clock outputs. The decision threshold level is adjustable and optimized by a system user. The system is also used in combination with a digital communications analyzer. A recovered clock of the CDR circuit provides trigger for the DCA. The system includes an electrical input connector. Optionally, the system triggers directly from an RF electrical input in substitution of an optical input.

Abstract: A system, method, and computer readable medium for passive optical network rogue optical network unit diagnostics, comprises, detecting an alarm of a network, correlating the detected alarm to a bandwidth map, and selectively disabling an optical network unit upstream to the detected alarm on the bandwidth map for a pre-determined interval.

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: Systems and methods for bandwidth doubling in an Ethernet passive optical network (EPON) enable an optical line terminal (OLT) to transmit downlink to at least one double rate optical network unit (ONU). The double rate transmission is preferably facilitated by use of single rate devices (OLT and ONU) functionally connected to provide the double rate capability. The methods include packet-by-packet multiplexing, bit-by-bit line code interleaving, doubling an inter-packet gap (IPG) length, defining windows of transmission for different transmission rates, using the 8B/10B code, removing the 8B/10B code from just the downlink transmission and symbol-by-symbol multiplexing is downlink transmissions from the double rate OLT.

Abstract: A single wavelength bi-directional RoF link apparatus for signal transmission in a TDD wireless system includes a main donor for receiving an RF signal of downstream data from an upper layer, electrooptic converting the received RF signal to an optical signal, and transmitting the converted optical signal via an optical fiber in response to a TDD switching signal received from the upper layer, or receiving an optical signal of upstream data via the optical fiber, opto-electric converting the received optical signal to an RF signal in response to the TDD switching signal received from the upper layer, and transmitting the converted optical signal to the main donor; and a remote for receiving the optical signal of the downstream data via the optical fiber from the main donor, opto-electric converting the received optical signal to an RF signal, and emitting the converted RF signal to a terminal via an antenna in response to a TDD switching signal generated by a switch timing signal generation circuit, or receiv

Abstract: A system, device, and method for supporting cut-through pats in an optical communication system involves obtaining hop count and quality of service information by an initiating device and using the hop count and quality of service information by the initiating device to make decisions relating to a cut-through path. The hop count and quality of service information is provided in a reply message that is sent by a terminating device and modified by intermediate devices between the initiating device and the terminating device. The terminating device sends the reply with a hop count equal to one and quality of service information for a first link (hop) toward the initiating device. Each intermediate device increments the hop count in the reply and adds quality of service information for a next link (hop) into the reply.

Abstract: The invention includes methods and apparatuses to adjust an optical signal transmitted through an optical amplifier, such as in a wavelength division multiplexed optical network. The methods and apparatus of the invention calculate polarization effects which cause degradation to the optical signal. A measurement of the polarization-related degradation of an optical signal is calculated by using at least one reference signal. In some embodiments of the invention, the reference signal is depolarized or has scrambled polarizations. The invention is typically used in long-haul optical networks.