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A coupling wave optical waveguide sensor was proposed, and realized by combining the ion-exchange and the sol-gel methods. The new optical waveguide (OWG) sensor is based on a stacked slab optical waveguide codirectional coupler, and proved to be advantageous over conventional OWG sensors. A gas sensor fabricated as an example easily detected 5 ppm H2S.
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Qing et al. (1996) studied this question.
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