Methane Optical Sensing System With Polarization Rotation Gas Cell

A methane optical sensing system using a single reflective optical polarization rotation gas cell is developed. The periodic ripple-like variation of interference light intensity in the common single reflective gas cell is analyzed, in terms of the calculated return loss and insertion loss of the cell. A novel single reflective optical polarization rotation gas cell is designed and demonstrated to adequately suppress the light interference effect. The efficacy of the new approach is demonstrated experimentally, showing that the accuracy of the new methane sensor using optical polarization rotation gas cell is better than the sensor using a common single reflective gas cell by 47 %.