We present a highly sensitive salinity sensor realized with a polyimide-coated polarization-maintaining photonic crystal
fiber (PM-PCF) based on a Sagnac interferometer configuration. The achieved salinity sensitivity is as high as 0.616
nm/M which is 37 times more sensitive than that of previous reported polyimide-coated fiber grating sensor. It has a low
temperature sensitivity of -0.0122 pm/°. The performance of the sensor in aqueous solution of NaCl with concentrations
up to 5.12 mol/L has been experimentally investigated. The proposed fiber optic salinity sensor is a promising candidate
for salinity measurement.
We proposed and demonstrated the application of a polarization-maintaining photonic crystal fiber for torsion sensing.
The sensor has high twist angle resolution and exhibits reduced temperature sensitivity, making it an ideal candidate for
A novel design of fiber Bragg grating (FBG) based accelerometer is proposed in this paper. The chirp-free mechanism on
the FBG sensing element is the methodology employed in this design. The sensor has the flexibility to apply different
mechanical parameters, and it shows excellent performance to different applied signals. The performance is then
optimized by varying different configuration of the sensor. Good sensitivity (18με/g) and signal-to-noise ratio (20.68dB
re nm/g) is easily achieved. Maximum input signal frequency up to 150Hz is able to be caught up by the specific
configuration of the accelerometer. The accelerometer also has the capability of capturing a full sine wave input signal
with the maximum peak-to-peak amplitude up to 3.9nm.