Contents 1 Introduction
Carbon monoxide (CO) is one of the most dangerous gases in air pollution and human life. CO is produced by incomplete combustion of fuels and commonly found in the emission of automobile exhausts, the burning of domestic fuels, etc. It is highly toxic and extremely dangerous because it is colorless and odorless. It is very harmful to human health. When CO is inhaled, it combines with the oxygen-carrying hemoglobin of the blood to form carboxyhemoglobin. Once combined with CO, the hemoglobin is no longer available for transporting oxygen. When the carboxyhemoglobin concentration in the blood reaches 15%, people become aware of a mild headache. Death is caused when the carboxyhemoglobin concentration reaches 50%. Therefore, CO sensors are required in various situations, such as industrial and home use. Fiber-optic sensors are ideal for this application as they can span a large surveillance area and provide a continuous in-stiu monitoring system[1]–[2]. Optical fiber gas sensor based on Near Infrared absorption has many advantages on traditional gas sensors. Fiber has very low transmission attenuation in near infrared spectrum region. So it is suitable to transmit for a long distance. This kind sensor can detect flammable and explosive gases. The sensor cell has a simple configuration and its performance is superior. And it is also easy to form fiber-optic sensor network.
