Random-hole optical fiber evanescent-wave gas sensing

• Published in: Optics letters 2004-07, Vol.29 (13), p.1476-1478
• Main Authors: PICKRELL, G, PENG, W, WANG, A
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Integrated optics. Optical fibers and wave guides; Optical and optoelectronic circuits; Physics; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Sensors, gyros
• ISSN: 0146-9592; 1539-4794
• DOI: 10.1364/ol.29.001476

Research on development of optical gas sensors based on evanescent-wave absorption in random-hole optical fibers is described. A process to produce random-hole optical fibers was recently developed that uses a novel in situ bubble formation technique. Gas molecules that exhibit characteristic vibrational absorption lines in the near-IR region that correspond to the transmission window for silica optical fiber have been detected through the evanescent field of the guided mode in the pore region. The presence of the gas molecules in the holes of the fiber appears as a loss at wavelengths that are characteristic of the particular gas species present in the holes. An experimental setup was constructed with these holey fibers for detection of acetylene gas. The results clearly demonstrate the characteristic absorptions in the optical spectra that correspond to the narrow-line absorptions of the acetylene gas, and this represents what is to our knowledge the first report of random-hole fiber gas sensing in the literature.