Childs Paul, Wong Allan C L, Fu H Y, Liao Yanbiao, Tam Hwayaw, Lu Chao, Wai P K A
Department of Electronic Engineering, Tsinghua University, Beijing, China 100084.
Appl Opt. 2010 Dec 20;49(36):6861-7. doi: 10.1364/AO.49.006861.
We measured the hydrostatic pressure dependence of the birefringence and birefringent dispersion of a Sagnac interferometric sensor incorporating a length of highly birefringent photonic crystal fiber using Fourier analysis. Sensitivity of both the phase and chirp spectra to hydrostatic pressure is demonstrated. Using this analysis, phase-based measurements showed a good linearity with an effective sensitivity of 9.45 nm/MPa and an accuracy of ±7.8 kPa using wavelength-encoded data and an effective sensitivity of -55.7 cm(-1)/MPa and an accuracy of ±4.4 kPa using wavenumber-encoded data. Chirp-based measurements, though nonlinear in response, showed an improvement in accuracy at certain pressure ranges with an accuracy of ±5.5 kPa for the full range of measured pressures using wavelength-encoded data and dropping to within ±2.5 kPa in the range of 0.17 to 0.4 MPa using wavenumber-encoded data. Improvements of the accuracy demonstrated the usefulness of implementing chirp-based analysis for sensing purposes.
我们使用傅里叶分析测量了一个包含一段高双折射光子晶体光纤的萨格纳克干涉式传感器的双折射和双折射色散对静水压力的依赖性。证明了相位和啁啾光谱对静水压力的敏感性。通过这种分析，基于相位的测量显示出良好的线性，使用波长编码数据时有效灵敏度为9.45 nm/MPa，精度为±7.8 kPa；使用波数编码数据时有效灵敏度为-55.7 cm⁻¹/MPa，精度为±4.4 kPa。基于啁啾的测量虽然响应是非线性的，但在某些压力范围内精度有所提高，使用波长编码数据时在整个测量压力范围内精度为±5.5 kPa，使用波数编码数据时在0.17至0.4 MPa范围内精度降至±2.5 kPa以内。精度的提高证明了实施基于啁啾的分析用于传感目的的有用性。
