Optical RF tone in-band labeling for large-scale and low-latency optical packet switches

We propose an RF tone in-band labeling technique that is able to support large-scale and low-latency optical packet switch. This approach is based on N in-band wavelengths, each carrying M radio frequency (RF) tones. The wavelengths and the tones have a binary value, and are able to encode 2N×M possible routing address. We develop an optical label processor for the RF tone in-band optical label based on parallel and asynchronous processing. It allows the optical packet switch with an exponential increase of number of ports at the expense of limited increase in the latency and the complexity. By using RF tone in-band labeling technique, we demonstrate error free (bit error rat

Single and Multicast Wavelength Conversion at 40 Gb/s by means of Fast Nonlinear-Polarization-Switching in an SOA

We experimentally demonstrate all-optical wavelength conversion of a 40-Gb/s nonreturn-to-zero signal by means of nonlinear polarization switching in a single semiconductor optical amplifier (SOA). Using a highly nonlinear SOA optimized for very fast gain recovery time, we observe no appreciable penalty for the conventional (single) wavelength conversion. We also obtain, for the first time by using this technique, the simultaneous multiconversion to different wavelengths (four on a 200-GHz frequency grid) of an input signa

All-Optical Clock Recovery for NRZ-DPSK Signals

We experimentally demonstrate an optical clock recovery scheme for nonreturn-to-zero differential phase shifting keying (NRZ-DPSK) data. By using an optical circuit made by a proper fiber Bragg filter and a Fabry-Pérot based clock extraction circuit, we obtain a stable and low jitter 10-GHz optical clock signal. This signal shows comparable performance with the original electrical clock in bit-error-rate measurements and oscilloscope triggering operation

WDM monitoring technique using adaptive blind signal separation

We present a cost-effective method of monitoring the performance of wavelength-division-multiplexed (WDM) channels. The method is based on simple optical signal processing in combination with electronic signal processing. The photocurrent of a detected (multi-channel) optical signal is analysed using an adaptive blind signal separation method. A maximum data decorrelation criterion is used to separate the WDM channels. We show experimentally that four WDM channels can be reconstructed accurately by this numerical method

Representations of Time Coordinates in FITS

In a series of three previous papers, formulation and specifics of the representation of World Coordinate Transformations in FITS data have been presented. This fourth paper deals with encoding time. Time on all scales and precisions known in astronomical datasets is to be described in an unambiguous, complete, and self-consistent manner. Employing the well--established World Coordinate System (WCS) framework, and maintaining compatibility with the FITS conventions that are currently in use to specify time, the standard is extended to describe rigorously the time coordinate. World coordinate functions are defined for temporal axes sampled linearly and as specified by a lookup table. The resulting standard is consistent with the existing FITS WCS standards and specifies a metadata set that achieves the aims enunciated above.Comment: FITS WCS Paper IV: Time. 27 pages, 11 table

A simple and low-power optical limiter for multi-GHz pulse trains

We study the limiting-amplification capability of a saturated Semiconductor Optical Amplifier (SOA) followed by an optical band-pass filter. We experimentally demonstrate that this simple optical circuit can be effectively exploited to realize a low-power optical limiter for amplitude-modulated pulse trains at multi-GHz repetition rate. We report very large amplitude-modulation-reduction factors for the case of 20 and 40 GHz pulse trains that are super-imposed with modulating frequencies ranging from 100kHz to several GHz. (C) 2007 Optical Society of America

All-optical label swapping of in-band addresses and 160 Gbit/s data packets

A 1×4 all-optical packet switch is presented, based on an optical label swapping technique that utilises a scalable label processor and a label rewriter with 'on the fly' operation. Experimental results show error-free packet switching with a data payload at 160Gbit/s. The label erasing and new label insertion operation introduces 0.5dB of power penalty. These results indicate a potential utilisation of the presented technique in a multi-hop packet switched network