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...

In this paper a polarimetric fibre-optics current sensor in a new highly versatile all-fibre configuration is described. The optical configuration is particularly simple and is based on a back-and-forth propagation through a twisted sensing fibre. This results in a very flexible sensing cable which can be adapted to a great number of existing power installations, by simply winding the fibre aro...

This paper presents a very brief overview of the principles which have evolved and the achievements which have accrued over almost half a century of fibre optic sensors. We cite a few examples of success stories along the way, but the very diverse nature of optical fibre sensor technologies of necessity infers that these few examples will be but representative and many are omitted. We also spec...

Tunable lasers are currently used in a wide range of applications such as wavelengthdivision-multiplexing networks, optical sensors, spectroscopy, wavelength protection, fiberoptic gyroscope, and testing of optical components and instruments. In particular, tunable fiber lasers, which employ optical fiber cavity and wave-guided gain medium, have recently attracted great interest owing to severa...

Fibre materials span a broad range of applications ranging from simple textile yarns to complex modern fibre-optic communication systems. Throughout their history, a key premise has remained essentially unchanged: fibres are static devices, incapable of controllably changing their properties over a wide range of frequencies. A number of approaches to realizing time-dependent variations in fibre...

Fibre type determination requires a large series of differently stained muscle sections. The manual identification of individual fibres through the series is tedious and time consuming. This paper presents a software that enables (i) adjusting the position of individual fibres through a series of differently stained sections (image registration) and identification of individual fibres through t...

Both phase and group velocities of all guided modes of a moderately multimode fibre are experimentally determined from a single sample. Modes are excited by a picosecond optical pulse and spatially separated at the etched fibre end. A picosecond streak camera records their spatial and temporal output coordinates.

A spectral-hole created by locally pressing a fibre Bragg grating (FBG)s exhibited a wavelength-shift within the FBG bandwidth. A sensitivity of 74.3 pm/(N/mm) was obtained for pressure applied along the slow axis of a high birefringence fibre. ©2006 Optical Society of America OCIS codes: (060.2370) Fiber optics sensors; (060.2420) Fibers, polarization-maintaining