This paper addresses OFDM (orthogonal frequency division multiplexing) transmission over optical links with high spectral efficiency, i.e. by using high-order QAM-modulation schemes as a mapping method prior to the OFDM multicarrier representation. Here we address especially coherent optical OFDM modem in long distance. Numerical simulations of the coherent optical orthogonal frequency division...

We report the extension of hollow-core fibre pulse compression to longer wavelengths. High-energy multi-cycle infrared pulses are generated via optical parametric amplification and subsequently broadened in the fibre. 2.5-cycle pulses at the Signal wavelength (1.4 μm) and 1.6-cycle pulses at the Idler wavelength (1.8 μm) in the sub-millijoule regime have been generated. New compression schemes ...

Optical Amplifiers are essentials components in long haul fibre optic system. An amplifier is a electronic device that can increase the power of signal. An Optical Amplifier is effectively the opposite of attenuator while Optical Amplifiers provide gain and attenuator provides loss. When a signal travels in a optical fibre medium the signal suffer from various losses such as fibre losses, atten...

Introduction: High repetition rate optical pulses in a few picosecond range and below are playing an increasingly important role in high speed optical fibre communication systems. Such high repetition rate short pulses are routinely generated by harmonically modelocked lasers [1], but with the following limitations: (i) complicated feedback control is required; (ii) the modelocked frequency com...

Natural fibers can be attractive reinforcing materials in thermosetting polymers due to their low density and high specific mechanical properties. Although the research effort in this area has grown substantially over the last 20 years, manufacturing technologies to make use of short natural fibers in high volume fraction composites; are still limited. Natural fibers, after retting and preproce...

A promising route to manufacturing portable (sub-)picosecond fibre lasers is to use a semiconductor saturable absorber mirror (SESAM). With SESAMs, the mode-locked regime can be achieved for different values of cavity dispersion for a broad spectrum ranging from 0.8 to 1.6μm. The fibre lasers, characterized by a high efficiency and reliability and a small footprint, are very attractive for appl...

A derivation of the Dirac equation in ‘3 + 1’ dimensions is presented based on a master equation approach originally developed for the ‘1+ 1’ problem by McKeon and Ord. The method of derivation presented here suggests a mechanism by which the work of Knuth and Bahrenyi on causal sets may be extended to a derivation of the Dirac equation in the context of an inference problem.

In this paper, we compare the theoretical and simulated bit error rate (BER) performance of an all-optical active recirculating fibre loop buffer (RFLB) employed at the transmitter node of an optical time division multiplexed based (OTDM) system, for several buffer storage times (delays). To the best of our knowledge, we believe that this is the first time a theoretical model detailing BER perf...

It is well recognized that the measurements of optical rotatory dispersion of proteins with strong absorption bands are extremely difficult because of the diminishing intensity of the emergent light. Until very recently, these studies were made possible only by improving the light source and also frequently by a wide opening of the slit width on the monochromator at the expense of spectral puri...