Research on Quantum-Well Lasers for Gas Sensing

In the early 1980s, literature began to appear on gas concentration measurements using Tunable Diode Laser Absorption Spectroscopy (TDLAS). Thanks to its significant technical advantages over conventional spectroscopic detection methods, TDLAS technology quickly gained widespread adoption. Since the year 2000, research institutions and enterprises in China have conducted extensive studies on diode laser spectroscopy for detecting asymmetric gas molecules of inorganic compounds. In recent years, through technological cooperation and transfer, domestic research institutions have developed TDLAS-based online gas monitoring systems—relying on domestically produced technologies with independent intellectual property rights—that have already achieved notable success in applications such as mine operations, coal-to-gas monitoring, natural gas monitoring, and oil-and-gas field monitoring.

　　In the early 1980s, literature began to appear on gas concentration measurements based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) technology. Thanks to its significant technical advantages over conventional spectroscopic detection methods, TDLAS technology quickly gained widespread adoption. Since the year 2000, research institutions and enterprises in China have carried out numerous studies on diode laser spectroscopy for detecting asymmetric gas molecules of inorganic compounds. In recent years, through technological cooperation and transfer, domestic research units have developed TDLAS-based online gas monitoring systems—relying on domestically produced technologies with independent intellectual property rights—that have already achieved initial success in applications such as mine operations, coal-to-gas monitoring, natural gas monitoring, and oil-and-gas field monitoring. The key component of TDLAS technology is the infrared laser light source. We have developed light sources operating in the 1.6–2.0 μm wavelength range, including large-strain quantum-well Distributed Feedback (DFB) lasers and Distributed Bragg Reflector (DBR) lasers. These lasers exhibit threshold currents below 20 milliamperes, side-mode suppression ratios exceeding 40 dB, and fiber-coupled output powers greater than 8 milliwatts, achieving practical and effective performance. We have also successfully prepared small batches of narrow-linewidth distributed feedback lasers and completed the "Key Technology Research on Gas Detection Systems Based on Quantum-Well Lasers" project under the 863 Program. The resulting technologies have been applied in industries including coal-mine methane detection, oil-and-gas monitoring, automotive exhaust gas analysis, and medical breath analysis. Furthermore, we have provided long-term technical support to numerous domestic gas-sensor companies. The related achievements were honored with the Second Prize for Invention by the Chinese Institute of Electronics for "Key Technology Research on Gas Detection Systems Based on Quantum-Well Lasers."

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