Fa. Muhammad et al., SENSITIVITY ENHANCEMENT OF D-FIBER METHANE GAS SENSOR USING HIGH-INDEX OVERLAY, IEE proceedings. Part J, Optoelectronics, 140(2), 1993, pp. 115-118
The authors determine that the sensitivity of a D-fibre methane gas se
nsor can be improved by overcoating the flat surface of the fibre with
a high index layer. Using the finite-difference/perturbation theory t
echnique, the enhancement factor over uncoated D-fibre is computed. Th
e results compare favourably with those obtained from analytical expre
ssions and the matrix method for a planar waveguide structure which mo
dels the overcoated D-fibre. From theoretical results it is concluded
that the sensitivity can realistically be improved by an order of magn
itude over an uncoated fibre.