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Takamatsu-shi, Japan

Asahi I.,Shikoku Research Institute | Sugimoto S.,Shikoku Research Institute | Ninomiya H.,Shikoku Research Institute | Shimokawa F.,Kagawa University | And 5 more authors.
IEEJ Transactions on Sensors and Micromachines | Year: 2013

Compact optical gas sensors based on the Raman effect and ultraviolet absorption spectroscopy were developed. These sensors are miniaturized and do not require alignment, because the mirrors and optics are fixed onto a precisely machined micro optical bench made by micromachining technology. The Raman type gas sensor consists of a small DPSS laser (wavelength 532 nm, pulse energy 200 μJ, pulse width 3 ns, repetition frequency 1 kHz), the sensor chip, and the detector, which are connected by optical fibers. The UV absorption type gas sensor is consists of a D2 lamp, the sensor chip and a compact spectrometer, which are connected by optical fibers. The measured signals showed good linearity along with the gas concentrations. The limit of detection using the Raman effect was 1% for hydrogen or 0.2% for methane, and the minimum limit of detection using ultraviolet absorption spectroscopy was 10 ppm for ammonia and sulfur dioxide for an optical path length of 20 mm. Source

Ito M.,Kagawa University | Takeda T.,Kagawa University | Suzuki T.,Kagawa University | Takao H.,Kagawa University | And 8 more authors.
IEEJ Transactions on Sensors and Micromachines | Year: 2013

In order to realize the miniaturization of the optical gas sensors by the passive alignment of optical components, we proposed a micro-optical bench which consists of a guiding groove and a micro-mirror with an ultra-thick resin structure. We fabricated the micro-optical bench with an ultra-thick resin structure of 2 mm height and processing accuracy of within ±10 μm. By using this micro-optical bench, compact optical multi-gas sensors (size: 3 cm×3 cm) by the passive alignment through a guiding groove for a ball lens and a fiber ferrule were realized. © 2013 The Institute of Electrical Engineers of Japan. Source

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