F. Ramos

IST-LASAGNE: towards all-optical label swapping employing optical logic gates and optical flip-flops

The Information Society Technologies-all-optical LAbel SwApping employing optical logic Gates in NEtwork nodes (IST-LASAGNE) project aims at designing and implementing the first, modular, scalable, and truly all-optical photonic router capable of operating at 40 Gb/s. The results of the first project year are presented in this paper, with emphasis on the implementation of network node functionalities employing optical logic gates and optical flip-flops, as well as the definition of the network architecture and migration scenarios.

All-optical switching structure based on a photonic crystal directional coupler

A novel all-optical switching structure based on a photonic crystal directional coupler is proposed and analyzed. Efficient optical switching is achieved by modifying the refractive index of the coupling region between the coupled waveguides by means of an optical control signal that is confined in the central region. Small length (around 1.1 mm) and low optical power consumption (over 1.5 W) are the main features estimated for this switching structure.

All-optical flip-flop based on a single SOA-MZI

A novel architecture of an all-optical flip-flop is proposed. The architecture is comprised of a single semiconductor optical amplifier-based Mach-Zehnder interferometer with a feedback loop. The simulation results show that low switching energies (<2-pJ pulses) and fast operation (<1-ns response delays) may be achieved.

From IP over WDM to all-optical packet switching: economical view

In this paper, a technoeconomical study of several (optical) packet-switching node architectures is described. Therefore, different architectures proposed in IST-WASPNET and IST-LASAGNE projects as well as a standard optical circuit switching approach are considered, and their economical impact is estimated by means of cost comparisons between the different technologies. The switching architectures all use optical fiber as a transport medium, but each of them uses a different technology to process switching. Their cost is evaluated as a function of most characteristic parameters for each technology. In the all-optical approaches, the main cost is that related to the fiber assembly, whereas for electronic processing, the most expensive cost is related to the optical-electronic-optical (OEO) conversions. The results show that the integration of optical components is crucial to make all-optical packet-switching nodes feasible.

All-optical network subsystems using integrated SOA-based optical gates and flip-flops for label-swapped networks

In this letter, we demonstrate that all-optical network subsystems, offering intelligence in the optical layer, can be constructed by functional integration of integrated all-optical logic gates and flip-flops. In this context, we show 10-Gb/s all-optical 2-bit label address recognition by interconnecting two optical gates that perform xor operation on incoming optical labels. We also demonstrate 40-Gb/s all-optical wavelength-switching through an optically controlled wavelength converter, consisting of an integrated flip-flop prototype device driven by an integrated optical gate. The system-level advantages of these all-optical subsystems combined with their realization with compact integrated devices, suggest that they are strong candidates for future packet/label switched optical networks

All-optical flip-flop based on an active Mach-Zehnder interferometer with a feedback loop.

A novel architecture for an all-optical flip-flop is validated experimentally. The architecture comprises a single semiconductor optical amplifier-based Mach-Zehnder interferometer with an external feedback loop. The experimental results show optical bistable operation for a latching device with an on-off contrast ratio of 11 dB that employs set and reset pulses of less than 250 pJ, although the energy of these pulses could be greatly reduced by optical integration of the whole device.

All-optical address recognition scheme for label-swapping networks

A two-bit all-optical correlator based on cascaded logic XOR gates is demonstrated with 10-Gb/s optical labels. Error-free operation with 13-dB extinction-ratio performance is achieved after the second stage by adjusting the label signal input power. The signal degradation at the device output is mainly caused by the accumulated amplified spontaneous emission noise from each active Mach-Zehnder interferometer. The experimental results show the feasibility of this architecture to perform address-recognition functionalities in photonic routers.

Generalized study of dispersion-induced power penalty mitigation techniques in millimeter-wave fiber-optic links

The authors present a comprehensive analysis of the chromatic dispersion effects in harmonic upconverted millimeter-wave (mm-wave) fiber-optic links. The optical upconversion is performed through a photonic mixer based on a Mach-Zehnder electrooptical modulator. It is shown that by biasing the electrooptical modulator either at the maximum or at the minimum transmission bias points, the dispersion-induced power penalty effect on the upconverted signal may be sharply mitigated, which results in increasing the frequency-length product of the fiber-optic link. Experimental results are provided for the three different types of bias.

All-optical packet routing scheme for optical label-swapping networks

A novel scheme for all-optical label reading and packet routing is proposed. The architecture is comprised of all-optical logic XOR gates and all-optical flip-flops based on single Mach-Zehnder interferometers incorporating semiconductor optical amplifiers (SOA-MZIs). The simulation results show that a very small penalty (less than 0.45 dB) for 10 Gbit/s packet processing can be achieved.

160-Gb/s All-Optical Packet Switching Over a 110-km Field Installed Optical Fiber Link

Demonstration of all-optical packet switching at 160 Gb/s over a total of 110-km field installed optical fiber link is reported. The packet switch architecture is based solely on photonic circuits: an optical filter as label processor, an all-optical flip-flop as memory element and an ultrafast wavelength converter as router. Both flip-flop and wavelength converter uses semiconductor optical amplifiers which allows for photonic integration. The switch operates at low power levels and shows potential scalability. Error-free operation is shown without forward error correction technology.