Abstract
We report performance optimization of hollow-core photonic bandgap fiber (HC-PBF) photothermal (PT) gas sensors. The PT phase modulation efficiency of a C2H2filled HC-PBF (HC-1550-02) is found independent of the pump modulation frequency for up to ∼330 kHz, but starts to drop quickly to 10% of the maximum value at a couple of megahertz. With a 1.1 m long HC-PBF gas cell with angle-cleaved single-mode fiber/HC-PBF joints to reduce reflection and a modified 3 × 3 Sagnac interferometer with balanced detection for phase demodulation, a noise equivalent concentration of ∼67 ppb C2H2is achieved with a 1 s time constant, and it goes down to ∼18 ppb with 145 s integration time. The system has good long-term stability and exhibits signal fluctuations of <1% over a ∼5 h period.
| Original language | English |
|---|---|
| Pages (from-to) | 4712-4715 |
| Number of pages | 4 |
| Journal | Optics Letters |
| Volume | 42 |
| Issue number | 22 |
| DOIs | |
| Publication status | Published - 15 Nov 2017 |
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics