Développement de capteurs à fibre optique basés sur la résonance ...

Article i
Submitted to Thin Solid films
3. Experiments
3.1 Experimental set-up
laser diode
celifor aqueous media
photodiode
comp uter for control
and data acquisition
Fig.6. Schematic diagram of the experimental set-up
The measurements were performed on the experimental set-up illustrated in figure 6. The
fiber was mounted through a small cell where the sample solutions were contained. The
sensor was illuminated by a polarized parallel beam of 670nm wavelength emitted from a
collimated laser diode which was installed on a precision rotator. The light power transmitted
out of the fiber was completely collected by a photodiode. The photovoltage was amplified,
giving a reading proportional to the transmitted light power. All controls and the dataacquisition
were automated by using a computer. The tested samples with definite indices
monitored by an Abbe refractometer were prepared by diluting ethylene glycol (n= 1.43 10)
with distilled water (n=l .333).
3.2 Deposition of the Zr02 overlay by sol-gel
A 15mm length of cladding was removed by mechanical and chemical methods [2,3] from
the middle of the 21 Omm long multimode step-index silica/silicone optical fiber (Quartz et
Silice PCS 600). The silver film was deposited on the uncladded part of the fiber core via
thermal evaporation. The coating of Zr02 overlay was put into effect by sol-gel just after the
fiber was taken out of the vacuum chamber.
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