Hercules Avramopoulos

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.

20 Gb/s all-optical XOR with UNI gate

All-optical Boolean XOR is demonstrated on a 20 Gb/s pseudodata pattern using a semiconductor optical amplifier-based ultrafast nonlinear interferometer (UNI) switch. Bit pattern switching with low-pattern dependence and low switching energies is achieved.

All-optical signal Processing and applications within the esprit project DO/spl I.bar/ALL

This paper reviews the work performed under the European ESPRIT project DO/spl I.bar/ALL (Digital OpticAL Logic modules) spanning from advanced devices (semiconductor optical amplifiers) to all-optical modules (laser sources and gates) and from optical signal processing subsystems (packet clock recovery, optical write/store memory, and linear feedback shift register) to their integration in the application level for the demonstration of nontrivial logic functionality (all-optical bit-error-rate tester and a 2/spl times/2 exchange-bypass switch). The successful accomplishment of the projects goals has opened the road for the implementation of more complex ultra-high-speed all-optical signal processing circuits that are key elements for the realization of all-optical packet switching networks.

Clock recovery circuit for optical packets

We demonstrate an all-optical clock recovery circuit for operation with short data packets of 10-Gb/s rate. The circuit uses a Fabry-Perot etalon and a nonlinear UNI gate and is capable of acquiring the clock signal within a few bits.

All-optical packet address and payload separation

An all-optical address and data separation scheme is presented for short 10-Gb/s packets. The technique uses a novel packet clock recovery circuit that consists of a Fabry-Perot filter and a ultrafast nonlinear interferometer (UNI) gate to generate a local packet clock. A second cascaded UNI gate is used to separate the header and the payload, performing a simple AND operation between the packet and its self-derived clock. The proposed technique requires a small number of bits as guard band and this number is independent of the line rate.

10 x 30 GHz pulse train generation from semiconductor amplifier fiber ring laser

A multiwavelength, fiber ring laser source, is demonstrated. It generates 10 wavelength channels, simultaneously mode-locked and synchronized at 30 GHz, each producing 7-ps pulses. The mode-locking technique relies on the gain saturation of the semiconductor amplifier from an external optical pulse train to impose the simultaneous mode-locking of the 10 wavelengths.

Optical Static RAM Cell

We demonstrate an optical static random access memory cell that provides read and write functionality at 5 Gb/s. The circuit comprises a hybridly integrated semiconductor optical amplifier-Mach-Zehnder interferometer (SOA-MZI) flip-flop serving as the memory unit and two additional SOA-based cross-gain modulation switches for controlling access to the memory cell.

Multiwavelength and power equalized SOA laser sources

Multiwavelength and power-equalized operation is demonstrated in a semiconductor optical amplifier ring laser that uses a fiber Fabry-Perot filter. By using single-pass optical feedback, the power-equalized oscillating spectrum is broadened so that simultaneous oscillation of 52 lines spaced at 50 GHz is achieved. The lines had 500 MHz width were power-equalized to within 0.3 dB and the extinction was better than 32 dB.

All-optical arbitrary demultiplexing at 2.5 Gbits/s with tolerance to timing jitter

All-optical demultiplexing has been shown with a full-duty-cycle 2.5-Gbit/s signal in a nonlinear fiber Sagnac interferometer. Complete switching of arbitrary pulse patterns in the data stream has been achieved by using two orthogonal polarization states for the switching and switched pulse trains. The polarization dispersion between the two fiber axes defines a window that allows for switching with timing errors as large as 350 ps.

30 Gb/s all-optical clock recovery circuit

All-optical clock recovery is demonstrated from pseudo-data patterns at 30 Gb/s. The circuit is based on the optical gain modulation of a semiconductor optical amplifier fiber laser. The recovered clock is a 2.7-ps pulse train, with very low modulation pattern even in the presence of more than 200 consecutive 0s in the data signal.