Highly scalable optical TDM router using a computer controlled time slot selector with picosecond resolution

An OTDM router architecture using a highly scalable time slot tuner is discussed. Results for a 100-Gb/s, 16-channel router using a computer-controlled interface are presented. The scalability and latency of the router based upon the time slot tuner shows that aggregate bandwidths beyond 1 Tb/s are possible. We show that a maximum hardware time slot access latency of less than 3.2 ns can be achieved with this architecture enabling ultrafast optical packet routing

TDM 100 Gb/s packet switching in an optical shuffle network

The feasibility of achieving large throughput in a single wavelength channel using TDM is discussed. The system is implemented with electronic routing control having networks that are often referred as transparent optical networks. The processing time required by the electronic routing controllers depends on the complexity of the routing algorithm employed, so it is critical to develop simple and efficient routing schemes. The system demonstrated packet switching in an 8-node shuffle networks using a physical node by connecting the two output links back to one of the input links using 500 m of fiber. The routing controller traces the path of a test packet by reconfiguring the node identified after performing switching on the test packet

Comparison of three nonlinear interferometric optical switch geometries

We present an experimental study of ultrafast all-optical interferometric switching devices based upon a resonant nonlinearity in a semiconductor optical amplifier (SOA). We experimentally compare three configurations: one based upon a Sagnac interferometer and the other two based upon Mach-Zehnder interferometers. By using picosecond pulses, we characterize the switching window of the three devices in terms of both temporal width and output peak-to-peak amplitude. These results are found to be in close agreement with a previously developed theoretical model. Since these nonlinear interferometric switches use an active device as the nonlinear element, relatively low control pulse energy is needed to perform switching as compared to other techniques. As a result, these optical switches are practical for all-optical demultiplexing and ultrafast optical sampling for future lightwave communication systems

Analysis of a rapidly reconfigurable multicast capable photonic switched interconnect

We present a complete mathematical formalism for a rapidly reconfigurable gated timeslot tuner based on a serial feed-forward structure. This gated serial timeslot tuner has been a key component for various demonstrations including a 100 Gb/s photonic switched interconnect [K.-L. Deng, R.J. Runser, P. Toliver, I. Glesk, P.R. Prucnal, J. Lightwave Technol. 18 (2000) 1892]. Design constraints for the proper operation of the interconnect are developed. Methods to predict feasible multicast combinations and control patterns required for driving the timeslot tuner are presented in terms of a two-dimensional (2D) contour map

Microwave Method for Locating Surface Slot/Crack Tips in Metals

The detection of exposed (empty and filled) and dielectric covered fatigue/surface cracks on metal surfaces is an important practical issue. Recently, microwave techniques have shown the potential of detecting exposed and dielectric filled cracks and cracks covered with dielectric coatings (i.e. paint). An important issue associated with these investigations is locating the tips of a crack. This is particularly important from the repair point of view in steel bridges and other structures. In this study openended rectangular waveguide probes are used to locate the tip of empty, dielectric filled, and covered cracks. In this paper the results of extensive measurements are discussed, including the accuracy by which the tip location of a crack may be determined. The location of a crack tip can be determined using a two-dimensional crack characteristic signal (image of the crack), and more simply and accurately by using the crack tip characteristic signal. For cracks/slots used in this study, the results indicate that the tip location of exposed (empty and filled) cracks may be identified to within 0.25 mm (0.009 in.) of their actual position, while covered crack tips are located within 2 mm (0.08 in.) of their actual locations. Using optimized measurement parameters and/or a higher order mode detection scheme may result in improved tip location accuracy. Good agreement is obtained between the results of a theoretical model and the measurements, which strongly indicates the possibility of theoretically optimizing (increasing) the accuracy by which a crack tip location may be determined

All optical code drop unit for transparent ring networks

In this letter, we propose and experimentally demonstrate a novel all-optical two-dimensional time-wavelength optical code-division multiple access (OCDMA) code-drop unit for transparent ring networks. The ultrafast all-optical code-drop unit is based on the terahertz optical asymmetric demultiplexer.We have demonstrated experimentally the capability to drop the correlated code at the desired node in a four-user ring network operating at 253 Gchips/s with a single-user bit rate of 2.5 Gb/s. Error-free operation is obtained. Dropping codes from multihop networks facilitates the development of optical add–drop multiplexers for OCDMA network

Fast tunable parallel optical delay line

A new tunable optical delay line for OTDM applications can achieve sub-nanosecond tuning time across three time slots spaced 100ps apart. Using parallel fiber delays, the delay line requires only one modulator operating below the baseband data rate. A simple control algorithm based on a latency diagram can further reduce the average latency beyond that of the straightforward hardware implementation by 50%. Using the demonstrated delay line, 10 GHz electronics has the potential to access a throughput of 160Gb/s optical data

TOAD having enhanced extinction ratio of the switching window

A Terahertz Optical Asymmetric Demultiplexer (TOAD) having preferably two non-linear elements (NLES) in which the extinction ratio is enhanced by saturating both NLEs when closing a switching window. A data signal input on one port of the TOAD is split onto two optical paths, each including one NLE. The optical paths converge at an output port. To start a switching window, a first control signal is input on an optical path that includes only one of the two NLEs. To close a switching window, one or more control signals are input such that both NLEs receive a control signal at a predetermined time after the first control signal is received by one of the NLEs. Only data signals passing through the first NLE during the switching window are output on the output port. Since both NLEs receive a second control signal at the same time, they decay together and thus avoid creation of unintended switching windows. Additionally, in certain embodiments of the present invention, the second control signal can be input on the data port or the output port, eliminating the need for a separate port for the second control signal as required by certain known TOADs

Generation, routing, and detection of 100 GSa/s arbitrary analog optical waveform packets using analog optical TDM

The concept of applying ultrafast optical time division multiplexing (TDM) techniques to enable the generation and detection of high-bandwidth analog waveform packets are introduced. Initial experiments with the analog optical TDM system shows that these techniques can provide great deal of control on the waveform profile. In addition, by appending the analog waveform to a high-speed digital header, more complex system functions, such as self-routing of analog waveforms throughout an interconnection network, are made possible