Since 2011, optical wireless communication (OWC) technologies have gained momentum. OWC has been supported by an active research community, and entrepreneurs who have shown the merits of these technologies by showcasing real-time demonstrators and commercial OWC solutions. These technologies include visible light communications (VLC), underwater VLC, Li-Fi, optical camera communications (OCC), visible

Downlink data transmission of multi-user indoor optical wireless communications and its corresponding fairness analysis is studied by the authors. It is assumed that access points (APs) may use infrared beam (IR-beam) laser or light emitting diodes (LEDs) for data transmissions. For the case of APs with IR-beams, since the bandwidth of the transmitted optical signal can be very large than that of the

Brillouin optical time-domain reflectometry (BOTDR) is a branch of distributed fibre-optic sensors, and it can measure the strain and the temperature information, localised by the return time of the probe pulse, along the fibre based on the spontaneous Brillouin scattering process. Parameters of the BOTDR system, including the spatial resolution, the signal-to-noise ratio, the measurement speed, and

1 INTRODUCTION This Special Issue highlights topics relating to recent research advances in optical communications, optical sensing and laser applications, emphasising fibre-optic communication systems/sub-systems; optical signal processing; optical fibre sensors and devices; and various applications of silicon photonics, modulators, and optoelectronic integration circuits. It brings together contributions

For a serial relaying underwater wireless optical communication (UWOC) system with ON-OFF keying modulation, we theoretically evaluate the optimal power allocation techniques in order to minimise the end-to-end bit error rate (BER), subject to transmission power constraints. At first, we evaluate the end-to-end BER with respect to all degrading effects of the UWOC channel, namely scattering, absorption

SF6 has been recognized worldwide as the main insulating gas for Gas-Insulated Switchgear (GIS). It is often required to accurately and effectively detect typical SF6 decomposition. In this paper, a sub-ppm-level SO2F2 and SOF2 gas sensor based on photoacoustic spectroscopy (PAS) is proposed and demonstrated. The steel resonant photoacoustic cell with a resonant frequency of 1750 Hz was designed and

A 1 × 48 large-scale multi-mode fibre (MMF) optical switch driven by a stepper motor is reported. The insertion loss is <1.42 dB, which can be further reduced to 1.02 dB after optimisation. With the employment of a corner cube prism in the optics, the device is characterised by good repeatability of <±0.01 dB. Meanwhile, the device has a fast response of <8 ms.

The microring modulator (MRM) is a small-size and low-power component, which is the potential for the next-generation optical interconnection. By the theoretical analysis, increasing the electrical bandwidth, which is relevant to the cross section and the doping concentration of the doping region, is a better way to increase electro-optical (EO) bandwidth. Therefore, a new doping profile of the PN

This paper investigates a high-quality and multi-purposed biosensor with maximum stable output transmittance numerically by using the inverse design method. The proposed biosensor utilises particle swarm optimisation for inverse design which will be a helpful way of designing different kinds of precise sensors in the future. In this research, some parameters are introduced to the optimiser to find