A remote fiber-optic methane gas sensor system is proposed and demonstrated with accurate gas concentration measurement and good mitigation of cross gas sensitivity. We use a polarization-maintaining photonic crystal fiber (PM-PCF)-based Sagnac loop filter to slice the spectrum of a broadband light source so as to precisely match several absorption lines of the methane gas within the near-infrared band. Meanwhile, a compact and cost-effective gas cell with multiple reflections is designed to enhance the interaction between the light beam and the methane gas to be detected, which also subsequently increase the system sensitivity. Due to the insensitive temperature dependence of the PM-PCF-based comb filter, we can obtain gas concentration measurement with a sensitivity of ~410 ppm. Moreover, by intentionally pumping the acetylene gas into the gas cell during the methane gas concentration measurement, the power variation caused by the interfering gas with 100% concentration is only equals to 0.7% of the power variation induced by the 100% concentration methane gas. Thus, effective mitigation of cross gas sensitivity is experimentally verified. The proposed fiber-optic methane gas sensor system is verified with low cost, compact size, potential capability of multipoint detection, and high sensitivity.

© 2012 IEEE

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription