Abstract: An optical communication system is provided comprising a transmission link including one or more quasi-static waveguide sections coupled by one or more non-static coupling sections. A transmitter is coupled to the transmission link and is adapted to transmit optical signals through the transmission link with wavelength channel spacing of the optical signals greater than about the PMD correlation bandwidth of at least one of the one or more quasi-static waveguide sections, such that the PMD induced outage probability for the system is optimized.

Abstract: A method and apparatus for receiving narrowband filtered optical PSK signals, including converting PSK optical signals into intensity-modulated signals at a receiver, and introducing a desired amplitude imbalance between the first and the second intensity-modulated signals to improve receiver performance.

Abstract: A load-balanced network architecture is disclosed in which a traffic flow deliverable from a source node to a destination node via intermediate nodes is split into parts, and the parts are distributed to respective ones of the intermediate nodes. Path delay differences for the parts are substantially equalized by delay adjustment at one or more of the intermediate nodes, and packets of one or more of the parts are scheduled for routing from respective ones of the intermediate nodes to the destination node based on arrival times of the packets at the source node.

Abstract: An apparatus and method for tunably delaying a signal and using that delayed signal in a duobinary transmitter is described. The transmitted duobinary signal is representative of the binary signal, and is formed by, among other things, introducing into a copy of the binary signal a delay that may be adjusted to be greater than or less than the bit period of the signal. Once the binary signal has been converted into a duobinary signal, it may then be converted into an optical duobinary signal. Alternatively, the conversion from binary to duobinary in accordance with the invention may be performed in the optical domain.

Abstract: A linear optical sampling apparatus, temporally samples a modulated optical signal using the amplitude of the interference of its electric field with the electric field of a laser pulse. The apparatus includes a 90° optical hybrid that combines the optical signal and laser pulse in order to generate two quadratures interference samples SA and SB. A processor compensates for optical and electrical signal handling imperfections in the hybrid, balanced detectors, and A/D converters used in the optical sampling apparatus. The processor numerically scales the two quadratures interference samples SA and SB over a large collection of samples by imposing that the average <SA>=<SB>=0 and <SA2>=<SB2> and then minimizes 2<SA·SB>/(<SA2>+<SB2>)=cos(?B??A)). This is done by adjusting the phase between the two quadratures (ideally either ??/2 or +?/2) so that cos(?B??A)) is zero.

Abstract: A load-balanced network architecture is disclosed in which a traffic flow at a given network node is split into a plurality of parts, and the parts are distributed to respective ones of the plurality of nodes that are designated as participating in a load balancing process for the traffic flow. Each of at least a subset of the participating nodes receiving one of the parts routes at least a portion of its received part to one or more destination nodes.

Abstract: A multi-channel optical equalizer for intersymbol interference mitigation compensates for single- or multi-wavelength channels simultaneously and requires few adjustable parameters. The optical equalizer also compensates for overshoots and signal transition degradations in semiconductor optical amplifiers. The equalizer unit uses one control signal for magnitude and one to control signal phase. The equalizer includes a controllable coupling ratio coupler for splitting the light into two portions and a controllable interferometer having two arms, one arm having an additional delay which is equal to an integer multiple of 1/?f, where ?f is the channel spacing between adjacent wavelengths utilized in the optical system. The controllable interferometer has a controllable delay in a first or second arm for adjusting the relative phase of the light passing therethrough. A coupler combines the two signal portions from the first and second arms to form the equalized output signal.

Abstract: An add-side laser in an optical device, such as an add/drop multiplexer OADM, provides not only a source for an add-side wavelength to be added to an output of the device, but also a reference for a receive-side coherent receiver that is included in the optical device.