Paul Toliver

Routing of 100 Gb/s words in a packet-switched optical networking demonstration (POND) node

This paper presents the design and experimental results of an optical packet-switching testbed capable of performing message routing with single wavelength time division multiplexed (TDM) packet bit rates as high as 100 Gb/s. The physical topology of the packet-switched optical networking demonstration (POND) node is based on an eight-node ShuffleNet architecture. The key enabling technologies required to implement the node such as ultrafast packet generation, high-speed packet demultiplexing, and efficient packet routing schemes are described in detail. The routing approach taken is a hybrid implementation in which the packet data is maintained purely in the optical domain from source to destination whereas control information is read from the packet header at each node and converted to the electrical domain for an efficient means of implementing routing control. The technologies developed for the interconnection network presented in this paper can be applied to larger metropolitan and wide area networks as well.

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.

Interferometric ultrafast SOA-based optical switches: From devices to applications

All-optical switches are fundamental building blocks for future, high-speed optical networks that utilize optical time division multiplexing (OTDM) techniques to achieve single channel data rates exceeding 100 Gb/s. Interferometric optical switches using semiconductor optical amplifier (SOA) non-linearities perform efficient optical switching with < 500 fJ of control energy and are approaching optical sampling bandwidths of nearly 1 THz. In this paper, we review work underway at Princeton University to characterize and demonstrate these optical switches as processing elements in practical networks and systems. Three interferometric optical switch geometries are presented and characterized. We discuss limitations on the minimum temporal width of the switching window and prospects for integrating the devices. Using these optical switches as demultiplexers, we demonstrate two 100-Gb/s testbeds for photonic packet switching. In addition to the optical networking applications, we have explored simultaneous wavelength conversion and pulse width management. We have also designed high bandwidth sampling systems using SOA-based optical switches as analog optical sampling gates capable of analyzing optical waveforms with bandwidths exceeding 100 GHz. We believe these devices represent a versatile approach to all-optical processing as a variety of applications can be performed without significantly changing the device architecture.

A highly-scalable, rapidly-reconfigurable, multicasting-capable, 100-Gb/s photonic switched interconnect based upon OTDM technology

We describe an ultrafast photonic switched interconnect based upon technologies developed for optical time division multiplexing (OTDM). The system uses a time-interleaved broadcast-and-select star architecture that is functionally equivalent to a crossbar switch. The interconnect offers full connectivity and low uniform latency among the input and output ports. The enabling technologies include ultrafast gated time slot tuners and all-optical demultiplexers. By utilizing these advanced optical technologies, it is possible to construct a highly scalable, rapidly reconfigurable, ultra-high-speed switch with performance beyond the capacity of current electronics. In the experimental demonstration, we constructed an interconnect with a peak bit rate of 100 Gh/s and the capability of connecting 16 OTDM ports. The system successfully demonstrated error-free operation of 100 Gb/s-multiplexing and demultiplexing in addition to rapid inter-channel switching capability on the order of the single channel bit period. The system also supports multicasting functions among many nodes. To scale the system to accommodate a large number of ports, we provide an analysis of the coherent crosstalk requirements through the network to show the potential to support hundreds of ports within practical constraints of the optical components. We believe that this system offers an approach to meet the demands of high bandwidth and fast switching capability required in current high-speed lightwave networks.

Simultaneous optical compression and decompression of 100-Gb/s OTDM packets using a single bidirectional optical delay line lattice

Using only a single bidirectional optical delay line lattice, we present a technique for performing ultrahigh-data-rate compression and decompression of optical time-division-multiplexed (TDM) packets for photonic packet switching networks. We also present the first experimental demonstration of simultaneous compression and decompression of 100-Gb/s optical TDM packets using our proposed structure.

All-optical clock and data separation technique for asynchronous packet-switched optical time-division-multiplexed networks

We propose and experimentally demonstrate an all-optical technique for separating a clock synchronization pulse from an optical time-division-multiplexed (OTDM) 100 Gb/s data packet. The technique is based on an all-optical switching device combined with optical feedback. This approach removes limitations found in other techniques such as those that are sensitive to long strings of zeroes in the data packet.

Comparison of three nonlinear optical switch geometries

Summary form only given. All-optical switches using ultrafast nonlinearities enable high aggregate data rates in optical TDM networks. These nonlinearities are based upon a resonant excitation in active or passive semiconductor optical amplifiers (SOA) or nonlinear waveguides. Extensive experimental demonstrations have been performed on various configurations of these devices. Optical switches which use an SOA as the nonlinear element are promising for future networks since they require low control pulse energy compared to passive devices.

Code Scrambling in Spectral Phase Encoded OCDMA Using Reconfigurable Integrated Ring Resonator Based Coders

We demonstrate code scrambling, implemented in ring-resonator based integrated coders, for enhanced degree of confidentiality in a spectral phase encoded OCDMA system. The BER performance with an interfering user is better than 1x10^-10.

Enhancement of out-of-band rejection in optical filters based on phase-sensitive amplification

We present a novel optical filter based on amplification and deamplification in a phase-sensitive amplifier (PSA), whose out-of-band rejection is enhanced by slightly imbalancing the inputs to the PSA. The out-of-band rejection of the PSA-based filter with balanced input signal and idler powers is given by G2 in the optical domain, where G is the maximum phase-sensitive gain. By unbalancing the input to the PSA, the optical out-of-band rejection is significantly enhanced beyond G2, thus enabling filters with high rejection even with moderate-gain PSAs. We demonstrate a filter with optical and electrical extinctions of 29xa0dB and 60xa0dB, respectively, using a moderate PSA gain of only 10xa0dB. Further, this technique allows for ultrawideband frequency tuning, spanning multiterahertz bandwidths along with filter response reconfigurability. These novel concepts will be invaluable for optical signal processing in high-performance analog and digital systems.

Ultrafast multihop packet-switched optical time-division multiplexing: components and systems

Ultrafast processing techniques for the implementation of high-speed all-optical packet-switched networks are reviewed. Some of the key technologies required for building the next generation of high-speed interconnection networks include ultrafast packet generation, high-speed packet demultiplexing, and efficient packet routing. A review of recent component, subsystem, and system development as well as experimental demonstrations being conducted at Princeton University is presented to illustrate some of the capabilities of these technologies.