| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact gas concentration measuring apparatus configured such that a sensor is formed into a perfect explosion-proof structure wherein no electric/electronic circuit is present and not restricted in the layout thereof. SOLUTION: The gas concentration measuring apparatus includes a light source unit containing a semiconductor laser device the laser emitting window of which undergoes antireflection processing, a resonator, the sensor containing a condensing system arranged in the direction crossing the resonator at a right angle, a detection unit containing a photodetector for detecting the Raman scattered light from measuring target gas and a control unit for calculating the concentration of the measuring target gas, a polarized wave holding optical fiber for connecting the light source unit and the sensor and an optical fiber for connecting the sensor and the detection unit, so that the laser beam emitted from the semiconductor laser device is entered into the resonator through the polarized wave holding optical fiber and part of the light in the resonator is returned to the oscillation unit of the semiconductor laser device through the polarized wave holding optical fiber to confine a linearly polarized laser beam in the resonator to thereby oscillate a laser beam of a narrow band locked in oscillation wavelength. COPYRIGHT: (C)2011,JPO&INPIT |
