A NEW GAS-DETECTION TECHNIQUE UTILIZING AMPLIFIED SPONTANEOUS EMISSION LIGHT-SOURCE FROM A TM+3 HO+3 CO-DOPED SILICA FIBER IN THE 2.0 MU-M REGION/

A new technique for the measurement of the concentration of gas specie s is presented. The method is based on absorption spectroscopy in the infrared region utilizing a high-power broad band amplified spontaneou s emission source from an optical fibre. Vibrational bands of CO2 gas in the range 1.9-2.1 mu m were measured and the relative intensities o f bands were calibrated in terms of concentration. The amplified spont aneous emission from a Tm+3/Ho+3 co-doped silica fibre pumped near 800 nm was used as a light source that consisted of the H-3(4) --> H-3(6) transition of the Tm+3 ion and the I-5(7) --> I-5(8) transition of th e Ho+3 ion with a full width at half maximum of 225 nm and total outpu t power over 1 mW. The technique has potential for the simultaneous de tection of multiple gas species due to its high spectral energy densit y over a wide wavelength band in the infrared where the vibrational ov ertones of gas molecules are located.