Investigation of the effect of the taper geometry on the sensitivity of tapered-fibre gas sensors

Abstract

In this paper, a comprehensive study is conducted to determine the optimum geometry for tapered fibre-optic gas sensors. A staircase concatenation method is introduced to investigate the effects of taper angle and fibre taper diameter on the sensitivity of the tapered-fibre sensors. The simulations show that the sensitivity of the tapered fibre-optic sensor increases by increasing the taper angle and reducing the taper diameter. To evaluate the predictions of the presented model, different tapered-fibre sensors have been fabricated and tested. The surface of the tapered fibres has been coated with palladium in order to determine the sensitivity of the sensors to hydrogen exposure. By increasing the percentage of the hydrogen in the surrounding environment, a shift of the output interference spectrum is observed. The experimental results confirm the simulation results obtained for the effect of geometry on the sensitivity of the sensors.

KEYWORDS:

• Tapered optical fibre
• evanescent waves
• fiber tapering
• refractive index sensor
• hydrogen detection

Acknowledgment

The authors gratefully acknowledge the partial support of this work from the Research Council of the Iran University of Science and Technology.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 Single mode fibre.

2 Free spectral range.