Abstract
The Internet of things (IOT) is one of the most popular research fields at present, and the optical fiber sensing network is an important part of the Internet of things. In the field of environmental protection and modern industrial production, there is a need for a sensor network which can monitor the gas concentration information. Because of the strong anti-interference ability, intrinsic safety, optical communication technology- based, intelligent monitoring and other significant characteristics, optical fiber gas sensing equipment and scheme has become the main direction of the field of domestic and foreign research. In this paper, we presents a 1665nm methane sensor structure based on single fiber coupler ring, and the performance of the sensor is analyzed, including the relationship between the optimal ratio of 1550nm coupler in the 1665nm system and the number of rings of signal light. Compared with the traditional absorption spectrum method, the effective absorption length of the chamber is increased 4 times by the sensor. Methane gas samples of two groups were measured by the sensor, and the measurement error was less than 2.5%.
