Temperature-insensitive relative humidity sensing based on a carrier-suppression-effect-free tunable optoelectronic oscillator using a non-coherent broadband optical source

摘要: Abstract A relative humidity (RH) sensing scheme with high resolution and interrogation speed based on an optoelectronic oscillator (OEO) is proposed experimentally demonstrated. carrier-suppression-effect-free single bandpass microwave photonic filter (MPF) no baseband response employed in the OEO to select oscillating frequency, which consisted of a non-coherent broadband optical source, Mach-Zehnder interferometer (MZI) one arm embedded phase modulator, dispersion compensation fiber photodetector. In MZI, section coated polyvinyl alcohol (PVA) film acting as probe, PVA can convert RH variation strain fiber. When changes, arm-length difference free spectral range MZI changed, leading frequency change MPF well signal OEO. By simply monitoring shift electrical domain, measurement be achieved. The temperature cross-sensitivity almost eliminated by adding without coating other MZI. An experiment performed, sensitivity 2.016 MHz/%RH 0.17 %