Temperature-Insensitive Bend Sensor Using Entirely Centered Erbium Doping in the Fiber Core

Harith Ahmad,Farah Muhammad,Mohd Zulkifli,Julian Samangun,Hairul Abdul-Rashid,Sulaiman Harun

doi:10.3390/s130709536

Harith Ahmad, Farah Muhammad + Show 4 more

Open Access

https://doi.org/10.3390/s130709536

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Journal: Sensors	Publication Date: Jul 23, 2013
Citations: 22	License type: CC BY 4.0

Affiliation: University of Malaya

Abstract

A fiber based bend sensor using a uniquely designed Bend-Sensitive Erbium Doped Fiber (BSEDF) is proposed and demonstrated. The BSEDF has two core regions, namely an undoped outer region with a diameter of about 9.38 μm encompassing a doped, inner core region with a diameter of 4.00 μm. The doped core region has about 400 ppm of an Er2O3 dopant. Pumping the BSEDF with a conventional 980 nm laser diode gives an Amplified Spontaneous Emission (ASE) spectrum spanning from 1,510 nm to over 1,560 nm at the output power level of about −58 dBm. The ASE spectrum has a peak power of −52 dBm at a central wavelength of 1,533 nm when not spooled. Spooling the BSEDF with diameters of 10 cm to 2 cm yields decreasing peak powers from −57.0 dBm to −61.8 dBm, while the central wavelength remains unchanged. The output is highly stable over time, with a low temperature sensitivity of around ∼0.005 dBm/°C, thus allowing for the development of a highly stable sensor system based in the change of the peak power alone.

Highlights

Fiber optic sensors have various industrial applications such as in monitoring of structural health [1,2,3], due to its advantages over electronic sensors such as being non-conducting, high sensitivity, resistivity to electromagnetic disturbance and robustness in erosive, conductive or explosive environments [4]
Besides the drawback of simultaneous temperature sensitivity, most fiber bend sensor designs use a separated gain medium and fiber sensing head, which will eventually increase the complexity of the sensor design
As can be seen from the figure, the peak power level of the Amplified Spontaneous Emission (ASE) spectrum reduces with the decrease of the EDF spooling diameter, from −57.0 dBm to −61.8 dBm at the spooling diameter of 10 cm and 2 cm respectively

Summary

Introduction

Fiber optic sensors have various industrial applications such as in monitoring of structural health [1,2,3], due to its advantages over electronic sensors such as being non-conducting, high sensitivity, resistivity to electromagnetic disturbance and robustness in erosive, conductive or explosive environments [4]. The bend sensor mechanism is realized by spooling the EDF at different diameters from 10 cm to 2 cm and the output ASE spectrum as well as the average output power is measured against the different spooling diameters.

Results

Conclusion