Abstract: Optical single sideband (OSSB) signals are conventionally generated using a dual-drive Mach–Zehnder modulator (MZM) or by using a single-drive MZM in conjunction with a fibre Bragg grating filter. In this study, the authors propose and mathematically characterise a novel radio over fibre downlink in which an OSSB signal is generated using a single-drive, rather than dual-drive, MZM wi...

Introduction: Polarisation mode dispersion (PMD) is an important factor in the performance of long-distance high speed optical transmission systems. There is clearly a need for a practical approach that supports the network provider’s planning and route design process for possible capacity upgrading in existing fibre plants, such as to retrofit 10 Gbit/s dense wave division multiplexing (DWDM) ...

A range of distributed fibre optic sensors for the detection and location of aqueous, chemical and hydrocarbon fluid spills is presented. The sensors incorporate polymers that convert the swelling into a localised loss on an optical fibre when fluid exposure occurs. Optical Time Domain Reflectometry (OTDR) techniques are employed to rapidly detect and locate target liquids and chemicals at mult...

Use of low-noise detectors can both increase the secret bit rate of long-distance quantum key distribution (QKD) and dramatically extend the length of a fibre optic link over which secure key can be distributed. Previous work has demonstrated use of ultra-low-noise transitionedge sensors (TESs) in a QKD system with transmission over 50 km. In this work, we demonstrate the potential of the TESs ...

Optical CDMA technology is being explored as a multiplexing technology for high speed access networks, with optical fibre as transmission medium and also processing ie. the spreading/dispreading of the CDMA sequences. For fibre-optic code division multiple access (FO-CDMA) scheme to be a practically implement able one as a high speed access network, two main challenges are, design of (1) codes ...

This paper addresses the particular need to develop suitable fabrication techniques of glasses to improve the radiation-resistance and extend the lifetime of optical fibres in high radiation background. Two radiation hardening techniques based on hydrogen and fluorine doping of glass have been applied on step index pure silica core optical fibres. The radiation-induced optical absorption and lu...

Introduction: Orthogonal frequency division multiplexing (OFDM) has been extensively investigated to combat RF microwave multipath fading, and has been widely implemented in various digital communication standards such as wireless local area network standards (WIFI IEEE 802.11a) [1]. In this Letter, we propose an optical equivalent of the RF OFDM called coherent optical OFDM (CO-OFDM) to combat...