Antiresonant Hollow-Core Fiber-Based Dual Gas Sensor for Detection of Methane and Carbon Dioxide in the Near- and Mid-Infrared Regions

Abstract

<jats:p>In this work, we present for the first time a laser-based dual gas sensor utilizing a silica-based Antiresonant Hollow-Core Fiber (ARHCF) operating in the Near- and Mid-Infrared spectral region. A 1-m-long fiber with an 84-µm diameter air-core was implemented as a low-volume absorption cell in a sensor configuration utilizing the simple and well-known Wavelength Modulation Spectroscopy (WMS) method. The fiber was filled with a mixture of methane (CH4) and carbon dioxide (CO2), and a simultaneous detection of both gases was demonstrated targeting their transitions at 3.334 µm and 1.574 µm, respectively. Due to excellent guidance properties of the fiber and low background noise, the proposed sensor reached a detection limit down to 24 parts-per-billion by volume for CH4 and 144 parts-per-million by volume for CO2. The obtained results confirm the suitability of ARHCF for efficient use in gas sensing applications for over a broad spectral range. Thanks to the demonstrated low loss, such fibers with lengths of over one meter can be used for increasing the laser-gas molecules interaction path, substituting bulk optics-based multipass cells, while delivering required flexibility, compactness, reliability and enhancement in the sensor’s sensitivity.</jats:p>

Recent Advancement of Anti-Resonant Hollow-Core Fibers for Sensing Applications

“…As shown in Figure 5c, laser-based dual gas sensing of methane and carbon dioxide is achieved by a length of 1m silica AR-HCF. The absorption wavelengths of these two gasses are 3.334 µm and 1.574 µm, respectively, corresponding to the near-and midinfrared spectral region [60]. That is, the monitoring crosstalk between methane and carbon dioxides can be well avoided, which paves the way for multi-component gas detection.…”

Laser-Based Trace Gas Detection inside Hollow-Core Fibers: A Review

“… SEM images of examples of NC HCFs: ( a , b ) revolver/tubular HCFs; ( c ) revolver/tubular HCF with double nested capillaries. ( a ) Reprinted from [ 65 ]; ( b ) reprinted with permission from [ 66 ], © The Optical Society; ( c ) reprinted with permission from [ 67 ], © The Optical Society. …”

Integrated Ammonia Sensor Using a Telecom Photonic Integrated Circuit and a Hollow Core Fiber

“…The combination of SOAs and PDs on the same circuit allows for several advanced spectroscopic configurations, such as having the reference arm on chip, or balanced detection schemes. Wavelength modulation spectroscopy (WMS) has been recently demonstrated in a HCF-based CO 2 and CH 4 sensor [14]. The picture shows the probe needle landed on the metal pad to inject current to the semiconductor optical amplifier (SOA) as well as the lensed fiber used for coupling.…”