Compact and wide range polarimetric strain sensor based on polarization-maintaining photonic crystal fiber

• A compact and wide range polarimetric strain sensor was demonstrated using polarization-maintaining photonic crystal fiber.
• The polarization-maintaining photonic crystal fiber used as the sensor head was as short as ∼2 cm.
• The measurement range was extended to 16 mɛ with a strain sensitivity of ∼1.01 pm/μɛ.
• The temperature sensitivity was measured as −12.3 pm/°C.
• The dependence of the strain sensitivity on the spectral detuning of the indicator dip was investigated.

We demonstrated a polarimetric fiber strain sensor based on Sagnac birefringence interferometer, which had a compact sensing element and wide measurement range. A short polarization-maintaining photonic crystal fiber (PM-PCF), the length of which was ∼2.0 cm, was employed as a sensor head. The length of the PM-PCF was reduced approximately by half, compared with the shortest one in the previous works. In particular, the measurement range was extended to 16 mɛ with a strain sensitivity of ∼1.01 pm/μɛ comparable to those of fiber Bragg gratings. Furthermore, the dependence of strain sensitivity on the wavelength shift of fringe dips was investigated to facilitate the practical use of the proposed sensor.