REVIEW ON STRUCTURES AND PRINCIPLES OF GAS CELLS IN THE ABSORPTION SPECTRUM–BASED OPTICAL FIBER GAS SENSOR SYSTEMS.

The main structures of the gas absorption cell, including small graded-index lens type, Bragg fiber type, photonic crystal type, etc., are compared in this article. Also, different principles of the gas absorption cell were discussed in detail in order to improve the sensitivity of the optical gas sensor. The study showed that the structure of gas cells plays a key role in the improvement of the sensitivity of optical gas sensors. The end of the article discusses the future direction of the development of the gas cell. [ABSTRACT FROM PUBLISHER]