David A. Jackson

Highly-multiplexed grating-sensors for temperature-referenced quasi-static measurements of strain in concrete bridges

A fibre-optic system for monitoring bridges with multiplexing support for >64 grating-based strain sensors is presented. Differential wavelength-demultiplexing controlled via LabView™ results in a system with 1με resolution, in-built temperature-referencing and readiness for commercial field-trials.

Acoustic detection using erbium fibre Bragg grating lasers

Fundamental limitations on the laser acoustic sensitivity were investigated over the range 200Hz to 20 kHz. Several laser sensors were wavelength division multiplexed along a length of fibre.

En-face OCT imaging of the retina using path modulation introduced by the transversal scanning mirror

The performance of an optical coherence tomography system using the phase modulation introduced by the transversal galvo-scanners is analyzed in terms of bandwidth, transversal resolution and image distortions. The method is illustrated by producing transversal and longitudinal images of the retina of the living eye.

Multiplanar OCT/confocal ophthalmoscope in the clinic

This paper demonstrates the clinical application of a multiplanar imaging system, which simultaneously acquires en-face (C-scan) OCT and corresponding confocal ophthalmoscopic images along with cross-sectional (B-scan) OCT at cursor designated locations on the confocal image. Advantages of the simultaneous OCT/confocal acquisition as well as the challenges of interpreting the C-scan OCT images are discussed. Variations in tissue inclination with respect to th coherence wave surface alters the sampling of structures within the depth in the retina, producing novel slice orientations which are often challenging to interpret. We evaluate for the first time the utility of C-scan OCT for a variety of pathologies including exudative ARMD, macular hole, central serous retinopathy, diabetic retinopathy, polypoidal choroidal vasculopathy and macular pucker. Several remarkable observations of new aspects of clinical anatomy were noted. The versatility of selective capture of C-scan OCT images and B-scan OCT images at precise points on the confocal image affords the clinician a more complete and interactive tool for 3D imaging of retinal pathology.

Simultaneous interrogation of fibre Bragg sensors for dynamic strain measurements

An opto-electronic processing system is described for quasi-simultaneous interrogation of 64 fibre Bragg grating dynamic strain sensors. Dynamic strain resolutions of 35n?/?Hz with a signal bandwidth <20Khz has been achieved.

Optical interferometric sensors in avionics applications: FLAPS (fly-by-light applications of photonic sensors)

An optical sensor system for an aerospace application that demonstrates a multi-measurement capability from a single, generic processing module is presented. The principle is applied to two diverse sensing tasks: proximity and hydraulic pressure measurements.

Fibre optic low coherence vibration sensor based on heterodyne detection

Non contact optical techniques have been extensively used in vibration sensing for a number of years, especially for the measurement of small amplitude vibrations [1]. Optical probing of the vibrating component has the advantage of being extremely sesnittive with a large dynamic range.

A Versatile System for Ocular Topographic Sensing Based on Two Low Coherence Interferometers

Low coherence interferometry has emerged in the last decade as a powerful and high nprecision investigative tool for various applications and recently in medicine and particularly in nophthalmology [1-3]. Configurations of two bulk interferometers [4] have already been nreported for investigations of the eye where they are used in tandem to eliminate axial eye nmovements. Our proposal is somewhat different, as we aim to have the potential of ntopographically sensing two regions in the eye by having the two interferometers independent nfrom each other.