We propose and demonstrate an interferometric sensor based on visibility modulation. In the interferometric sensor, a section of
polarization maintain (PM) fiber is spliced into one arm as the sensing head. Due to the interference between the two beams in the two
arms, respectively, an interferometric fringe can be obtained. The birefringence of the PM fiber splits the beam in the sensing arm,
yielding a visibility envelop in the interferometric fringe. Strain applied on the PM fiber can be demodulated by measuring the
visibility change in a given wavelength. Experimental result shows that the sensor can achieve resolution of up to 28 nano-strain. This
demodulation scheme is immunity to the wavelength shift and power fluctuation of OSA, thus improving the accuracy of the sensor.
This type of sensor can be improved by using a wavelength-swept laser or a mode-locked fiber laser.
The humidity sensor made of polymer optical fiber Bragg grating (POFBG) responds to the water content change in fiber induced by the change of environmental condition. The response time strongly depends on fiber size as the water change is a diffusion process. The ultrashort laser pulses have been providing an effective microfabrication method to achieve spatial localized modification in materials. In this work we used the excimer laser to create different microstructures (slot, D-shape) in POFBG to improve its performance. A significant improvement in the response time has been achieved in a laser etched D-shaped POFBG humidity sensor.
This paper proposed a solution about low cost multi-channels Gallium Arsenide (GaAs) absorption-based fiber optic
temperature sensing system, which can get specific channel temperature information at pre-set time slots by combining
time division multiplexing technology and fiber optic multiplexing module. Established an seven channels fiber optic
temperature sensing system using only one spectrum analysis unit and achieved -/+ 1°C temperature resolution, 2Hz
measuring frequency at temperature range from 0°C to 150°C.