The absorption and reduced scattering coefficients of turbid tissue phantoms have been determined from photothermal measurements made using an optical fibre probe. The thermal sensor was a thin polymer film positioned at the end of a multimode optical fibre. The film was illuminated by the output of a continuous-wave diode laser and formed the cavity of a low-finesse Fabry-Perot interferometer....

Introduction: In this Letter an optical fibre sensor capable of making fully distributed measurements of a wide range of solvents is identified. Microbending principles have been used to develop the sensor such that it responds on contact with liquid solvents, typically within 30 seconds of exposure. The sensor incorporates a swelling polymer and optical fibre components that are readily availa...

The optical fibre laser Doppler velocimetry (LDV) is a technique used for the velocity measurement of fluid flows. The two-dimensional directional LDV using a special technique based on generation of heterodyne signals of differential carrier frequencies has been described in literature [1,2]. The capability of simultaneous measurement of three orthogonal velocity components has also been prese...

Glass fibres with silicon cores have emerged as a versatile platform for all-optical processing, sensing and microscale optoelectronic devices. Using SiGe in the core extends the accessible wavelength range and potential optical functionality because the bandgap and optical properties can be tuned by changing the composition. However, silicon and germanium segregate unevenly during non-equilibr...

Network resilience is an issue of deep concern to network operators being eager to deploy high-capacity fibre networks, since a single failure in the network could result in significant losses of revenue. The importance of network reliability will keep pace with the steadily increasing network capacity. For very-high-capacity future optical networks, carrying multitudes of 10 Gbit/s channels pe...

The achievable information rates of optical communication systems using ultra-wide bandwidth 100-nm distributed Raman amplification have been investigated for each individual subchannels, based on the first-order perturbative analysis of nonlinear distortions. Introduction To date, optical fibre communications have achieved unprecedented growth and success over the past three decades and now st...

A model of an optical fibre communication line operating at 80 Gb/s with QPSK modulation format is studied numerically. The error statistics and patterning effects are analyzed and nonlinear transmission impairments of the optical signal are quantified.

A dual-peak LPFG (long-period fibre grating), inscribed in an optical fibre, has been employed to sense DNA hybridization in real time, over a 1 h period. One strand of the DNA was immobilized on the fibre, while the other was free in solution. After hybridization, the fibre was stripped and repeated detection of hybridization was achieved, so demonstrating reusability of the device. Neither st...

In this paper we present an in-ground intrusion detection system for security applications. Here, an optical fibre pressure switch is directly connected to a standard digital input of a programmable logic controller (PLC). This is achieved using an intensiometric detection system, where a laser diode and Fibre Bragg Grating (FBG) are optically mismatched, resulting in a static dc offset from th...

Photonic crystal fibre (PCF)–fibre bragg grating (FBG) integration opens up new possibilities in multi-parameter fibre-optic sensing, owing to their active control over light characteristics and mode confinements. Their integration results in a mismatch in their mode field diameters (MFDs), which in turn causes various types of losses such as confinement loss, scattering loss, etc. This paper p...