Showing papers by "Periklis Petropoulos published in 2002"

Demonstration of a four-channel WDM/OCDMA system using 255-chip 320-Gchip/s quarternary phase coding gratings

Abstract: In this letter, we report the fabrication and application of 255-chip 320 Gchip/s quaternary phase superstructure fiber Bragg gratings (SSFBGs) for optical code generation and recognition in a four-channel wavelength-division-multiplexing (WDM)/optical code-division-multiplexing (OCDM) experiment. Individual users of the system operate with different coding schemes, repetition rates, and wavelengths. Our experiments show that a single SSFBG can be used to perform simultaneous optical decoding and wavelength channel selection.

A grating-based OCDMA coding-decoding system incorporating a nonlinear optical loop mirror for improved code recognition and noise reduction

Abstract: We demonstrate an elementary grating-based optical code division multiple access (OCDMA) code generation and recognition system incorporating a nonlinear optical loop mirror (NOLM) within the receiver. We show that the NOLM can act as a nonlinear processing element capable of reducing both the pedestal associated with conventional matched filtering and the width of the associated code-recognition pulse. The pedestal rejection allows for an improved code recognition signal-to-noise ratio (SNR) relative to simple matched filtering alone, and reduced intra- and interchannel interference noise due to code overlap. The system benefits of using the NOLM are experimentally demonstrated under both single- and multiuser operation within a variety of seven- and 63-chip 160-Gchip/s code generation, recognition, and transmission experiments based on the use of bipolar superstructure fiber Bragg grating (SSFBG) coding-decoding pairs. Incorporation of the NOLM is shown to allow error-free penalty-free operation at data rates as high as 2.5 Gb/s under single-user operation, and to provide error-free performance with reduced power penalty in two-user experiments. The narrowed pulse recognition signature offers major advantages in terms of the further all-optical processing of decoded signals, such as code regeneration and recoding.

All-optical modulation and demultiplexing systems with significant timing jitter tolerance through incorporation of pulse-shaping fiber Bragg gratings

Abstract: In this letter, we demonstrate the use of a superstructured fiber Bragg grating to preshape optical pulses to obtain optimal operation of nonlinear all-optical switches. Specifically, we demonstrate the conversion of 2.5-ps soliton pulses into 20-ps rectangular pulses at the input to both fiber and semiconductor optical amplifier-based switches, and show that rectangular switching windows can be achieved thereby providing a 5-10-fold reduction in timing jitter sensitivity. Error free penalty free optical time-division-multiplexing switching was readily achieved over a /spl plusmn/7-ps timing mismatch range for the square pulse driven fiber nonlinear optical loop mirror switch versus a /spl plusmn/1-ps range for the switch driven directly with 2.5-ps laser pulses.

Apparatus for providing timing jitter tolerant optical modulation of a first signal by a second signal

Abstract: Apparatus for providing timing jitter tolerant optical modulation of a first signal (1) by a second signal (2), the first signal having a first wavelength (3), the second signal comprising a plurality of second signal pulses (4) having a second pulse shape (5) and a second wavelength (6), and the apparatus comprising a first signal input port (8), a second signal input port (9), a coupler (10), a grating (11) and a non-linear optical device (12), the apparatus being configured to direct the second signal (2) at the second signal input port (9) to the non-linear optical device (12) via the coupler (10) and the grating (11), and to direct the first signal (1) at the first signal input port (8) to the non-linear optical device (12); the grating (11) being a superstructured fibre Bragg grating that converts the second signal pulses (4) into intermediary pulses (13) each having an intermediary pulse shape (14); the intermediary pulse shape (14) being such that it provides a switching window (19) within the non-linear optical device (12).

A 10GBIT/S Tuneable Wavelength Converter Based on Four-Wave MIXING in Highly Nonlinear Holey Fibre

Abstract: We demonstrate a FWM based wavelength converter using a 15 m, highly nonlinear HF with a high SBS threshold. Error-free, efficient wavelength conversion of 10 Gbit/s NRZ signal over a ~10 nm bandwidth is reliably achieved

Advance Bragg Grating Devices and Where They Are Going

Abstract: Bragg gratings in optical fibre waveguides have now been around for nearly 25years and they were soon after being realised identified as one of the most significant fibre-optic inventions with potentials in a wide variety of areas among telecommunications equivalent to that of the erbium doped fibre amplifier. The highlight of some of the most recent advances in Bragg grating devices and applications in advanced components are discussed.

Advanced fibre Bragg gratings and where they are going

Abstract: Bragg gratings in optical fibre waveguides have now been around for nearly 25 years and they were soon after being realised identified as one of the most significant fibre-optic inventions with potentials in a wide variety of areas among telecommunications equivalent to that of the erbium doped fibre amplifier. Following their creation a plurality of infibre functions were thought possible with low or no insertion-loss. Although fabrication and control of vital grating parameters was limited in the early stages of their life, initially a number of filtering functions were identified for obvious demonstrations. It soon became apparent though that not just standard filtering manipulation was possible. Identifying the true potential of the devices has let to considerable effort being concentrated on their full exploitation implying building an infrastructure supported by theoretical design [2] and manufacturing techniques [3,4] around them. These techniques combined have let to a scenario where currently it is the imagination more than the actual design and manufacturing capabilities that imposes a limitation to what is being demonstrated. We will in this presentation discuss and highlight some of the most recent advances in Bragg grating devices and applications in advanced components. In particular we will show examples of the latest in Bragg gratings for dispersion-control, short pulse manipulation and advanced filtering applications and speculate into what the future holds for these unique devices.