Optimization measurement of hydrogen gas concentration by using high accuracy TDLAS

^(a) Information Technology R&D Center, Mitsubishi Electric Corporation, 5-1-1, Ofuna, Kamakura-shi, Kanagawa, Japan
^(b) Graduate School of Engineering, Chiba University, 1-33, Yayoicho, Inage-ku, Chiba-shi, Chiba, Japan
^(c) School of Engineering, Kyushu University, Fukuoka-shi, Fukuoka, Japan
^(d) Shikoku Research Institute inc., 2109-8, Yashimanishimachi, Takamatsu-shi, Kagawa, 9
^(e) Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa, Japan This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 9 April 2026

Abstract

Trace gas measurement is crucial for maintaining safety, quality control, and environmental protection across various industries. Tunable diode laser absorption spectroscopy (TDLAS) is frequently used for trace gas analysis due to its superior sensitivity and selectivity. However, the measurement of low concentrations of hydrogen gas using TDLAS presents challenges due to its lower absorbance compared to gases such as CO2, CH4, and NH3. In this study, we carried out laboratory-based experiments to evaluate a novel optimal method for detecting hydrogen gas, with the aim of facilitating remote sensing and establishing a foundation for lidar applications. By adjusting the gas cell pressure and line width, we optimized the center wavelength lock and the stable modulation of DFB-laser control. Further optimization involved maximizing the wavelength modulation spectroscopy signals through the careful selection of modulation parameters. This optimal method achieved a detection limit of 100 ppm with integration times of 30 seconds, while the stabilization of our TDLAS system exhibited a fluctuation of 55 ppm.