Abstract: An output signal of a single mode fiber (SMF) is spectrally shaped to achieve characteristics of a predefined channel “target” response. The target response is that of a partial-response, maximum-likelihood channel with additive white Gaussian noise. A receiver employs a maximum-likelihood sequence estimation (MLSE) detector having its detection algorithm, such as a Viterbi algorithm (VA), matched to the target response. Thus, state, branch, and path metric calculations for a Viterbi trellis may be optimized for a channel having this target response.

Abstract: An optical module according to the present invention includes: a light-emitting device that outputs laser light; a temperature adjustment unit that adjusts a wavelength of the laser light outputted from the light-emitting device so as to be locked at a predetermined wavelength; a wavelength monitor unit that receives laser light outputted from the light-emitting device by allowing the laser light to pass through an optical filter provided above the temperature adjustment unit and monitors the wavelength thereof; a package for sealing the light-emitting device, the temperature adjustment unit, and the wavelength monitor unit into the inside thereof; and a package temperature detection unit for detecting a temperature of the package, in which the temperature adjustment unit adjusts an oscillation wavelength of the laser light outputted from the light-emitting device to the predetermined lock wavelength based on a signal outputted from the wavelength monitor unit, and a signal from the package temperature detect

Abstract: A device and method for correcting for timing jitter of an optical data pulse in an optical transmission system. During transmission, a data pulse may suffer jitter. Its arrival time at a node may be temporally offset from its predicted arrival time. Data pulses are timed so that they may be received at a detector disposed downstream of the node at a predetermined time. The device includes a source of chirped optical pulses and a node, which has a first input arranged to receive a chirped optical pulse. The node has a second input arranged to receive a data pulse. The node includes an optical gate arranged to generate an output pulse in response to the first pulse and the data pulse received at the first and second inputs, respectively, having a wavelength dependent upon the time at which the data pulse is received at the second input. The device further includes an optically dispersive medium after passage through which, the output pulses are correctly retimed in order to correct for the timing jitter.

Abstract: A method and apparatus for remodulating an optical data stream such that a second modulated data stream is optically transported along with a first modulated data stream. In one embodiment, an optical signal having modulated thereon a first data stream is split into a plurality of reduced power optical signals, wherein at least one of the reduced power optical signals is remodulated to additionally include a second data stream. The first data stream is preferably Manchester encoded, the data rate of the second data stream is preferably one half the data rate of the first data stream.

Abstract: An iterative process is used to set the phase prechirp of a WDM optical transport system to a system's optimal level that maximizes the signal quality. A signal degradation factor takes into account linear and non-linear effects along the optical path and is used as a receive end feedback signal to control the phase prechirp level at the transmitter site. By using the FEC corrected errors rate as the feedback signal, optimization of signal quality is performed even when the system is running error free. By using an adaptive phase prechirp transmitter, signal degradation compensation can be also performed on a per wavelength basis to compensate for the residual dispersion slope and to allow optimization of individual channels independently of the net link dispersion value.

Abstract: A switch for optical signals, including a plurality of external inputs, a plurality of external outputs, a wavelength conversion entity and a plurality of core switching entities. Each core switching entity is associated to a respective set of at least two wavelengths. The approach is based on switching groups of at least two wavelengths in each core switching entity, while still maintaining per-wavelength switching granularity but sharing the provided capacity for wavelength conversion connections across the group. Thus, wavelength conversion resources assigned to a group of wavelengths are usable by any wavelength in that group. In this way, the blocking statistics in the node as a whole are improved with respect to a single-wavelength-plane configuration. In addition, the resulting switch is modular as it can be upgraded by adding or removing one or more switching modules as required.

Abstract: Device for detecting polarization mode dispersion of an optical data signal, which has at least one EXOR gate together with an averaging device for measuring at least one value of the autocorrelation function of a baseband signal distorted by polarization mode dispersion.

Abstract: A method is provided for establishing a service connection between first and second network nodes in a WDM optical network for a plurality of network users. The method begins by receiving, from each network user, user-preferences prioritizing a plurality of decision criteria defining preferable characteristics of the service connection. Next, a prescribed algorithm is used to select a path and a channel wavelength at which information is to be conveyed over the path between the first and second nodes. The selection is based on the plurality of decision criteria as prioritized in accordance with the user-preferences. Finally, the first and second network nodes are interconnected over the selected path with the selected channel wavelength.

Abstract: A coherent optical intradyne receiver is described which comprises an optical image reject mixer capable of dividing, mixing and recombining signals from three inputs so as to produce an inphase and a quadrature channel. On each of the channels a same set of image products is cancelled and from which channels, phase modulated signals can be recovered.

Abstract: A system and method providing for the detection of an input signal by distributing the input signal into independent signal components that are independently amplified. Detection of an input signal comprises generating from the input signal a plurality of spatially separate elementary charge components, each having a respective known number of elementary charges, the number of the plurality of spatially separate elementary charge components being a known monotonic function of the magnitude of said input signal; and independently amplifying each of the plurality of spatially divided elementary charge components to provide a respective plurality of signal charge packets, each signal charge packet having a second number of elementary charges greater than the respective known number by a respective amplification factor.

Abstract: A transmitter comprising a programmable optical vector modulator and method for coherent optical signal communication. The transmitter includes a transmitter laser whose output is coupled by way of an optical fiber to an amplitude modulator. The output of the amplitude modulator is coupled by way of a length of optical fiber to a phase modulator. The phase modulator generates a modulated light output from the transmitter. Amplitude modulation is achieved by inputting data and a data clock signal to amplitude symbol mapping logic whose outputs are selectively weighted, summed, amplified and input to the amplitude modulator to amplitude modulate the output of the transmitter laser.

Abstract: A controller for controlling a transceiver having a laser transmitter and a photodiode receiver. The controller includes memory for storing information related to the transceiver, and analog to digital conversion circuitry for receiving a plurality of analog signals from the laser transmitter and photodiode receiver, converting the received analog signals into digital values, and storing the digital values in predefined locations within the memory. Comparison logic compares one or more of these digital values with limit values, generates flag values based on the comparisons, and stores the flag values in predefined locations within the memory. Control circuitry in the controller controls the operation of the laser transmitter in accordance with one or more values stored in the memory. A serial interface is provided to enable a host device to read from and write to locations within the memory.

Abstract: A redundently modulated multicarrier protocol known as Carrier Interference Multiple Access (CIMA) is used in an optical-fiber network having wireless links at network nodes. CIMA is a protocol that can be used to create wireless protocols (such as TDMA and CDMA) having enhanced capacity and reduced system complexity. A CIMA optical-fiber network uses dispersion to enhance signal quality and facilitate switching. CIMA achieves both diversity benefits and capacity enhancements by providing redundancy in at least one diversity parameter while providing orthogonality in another diversity parameter. This basic operating principle of CIMA may be combined with multi-user detection to achieve frequency reuse and improved power efficiency. In the wireless link, diversity may be used to reduce the effects of small-scale fading on interferometry multiplexing.

Abstract: An optical regenerator enabling matching of self-phase modulation induced spectral broadening and optical regenerator filter center wavelengths and bandwidths for different fiber dispersion values. The regenerator monitors the central part of an input signal spectrum at the output of a non-linear medium and suppresses the power at the center wavelength to allow for a constant spectral broadening for different fiber dispersion values. The regenerator utilizes a control filter to control a variable amplifier via a feedback loop, and the variable amplifier adjusts the power of the signal launched into the non-linear medium to ensure a sufficient self-phase modulation broadened spectrum.

Abstract: A device and technique for aligning an optical carrier signal (e.g., a soliton pulse train) with a data signal in a transmitter. According to the invention, the device is configured to analyze the radio frequency (RF) spectrum of the transmitter's output. In one implementation, the device evaluates the amount of energy in a certain frequency band located near a selected null of the RF spectrum. In another implementation, the device examines the shape of the RF spectrum within that frequency band. In either case, based on the analysis, the device adjusts the phase of the clock signal driving an electro-optic (E/O) modulator in the transmitter. Such adjustment reduces misalignment between the optical carrier signal and data resulting, e.g., from thermal effects in the E/O modulator. The device may be used, e.g., in long-haul optical transmission systems operating at 10 GBit/s.

Abstract: According to the present invention, a system and method provides for monitoring and controlling light propagation in optical transmission systems. The system either includes an optical circulator coupled to an optical add mechanism and is used to detect light propagation, or an optical monitoring device is coupled to the optical circulator and to the optical add device via a feedback path to control light propagation.

Abstract: An alarm control method allowing easy localization of a failure in an optical communications network is disclosed. An optical signal from a signal transmitter is monitored to produce an alarm information signal indicating whether the optical signal is normally inputted. The optical signal and an optical control signal including the alarm information signal is multiplexed and transmitted to an optical receiver through an optical transmission line. When receiving the optical control signal and the optical signal from the optical transmitter, the optical receiver determines whether the optical signal is normally received. When not normally received, transmission of a receiver-side alarm signal to a management system is controlled depending on whether the alarm information signal indicates that the optical signal has been normally inputted at the optical transmitter.

Abstract: A module generally comprising a first transmitter, a detector and a controller. The first transmitter may be configured to transmit through a first physical channel of a connector. The detector may be configured to receive a first status signal but not receive user data through a second physical channel of the connector. The controller may be configured to adjust a power of the first transmitter in response to the first status signal.

Abstract: A data regenerator for regenerating a data signal, including a convertor for converting a received data signal into a binary data signal in dependence on conversion parameters, an error corrector for correcting errors in the binary data signal based on error correction code contained in the binary data signal to produce a corrected binary data signal, and a performance monitor for comparing the corrected binary data signal with an uncorrected representation of the binary data signal to determine information about the relative number of logic“1”s and logic “0”s that have been corrected by the error corrector and output a feedback signal representative of the relative number, wherein the convertor adjusts at least some of the conversion parameters in dependance on the feedback signal.

Abstract: An Optical Tapped Delay Line (OTDL) is combined with other known optical apparatuses to provide an add-drop multiplexer for a wavelength division multiplexing fiber optic network. Each output beam of the OTDL is spatially distinguishable in free space. This wavelength accessibility enables selection of one or more of the optical beams for adding or dropping. The system can be a fixed or tunable single channel add/drop system, a fixed or tunable multi-channel add/drop system, or a fully programmable add/drop system.