Fig. 1. Experimental setup for polarization measurement of the transmitted circularly polarized light through the PM fiber at different temperatures or powers of light. QWP: quarter-wave plate.

Fig. 2. (a) Cross section of a PANDA PM fiber. (b) An example of elliptically polarized light with ellipticity of 0.37 and angle of 135° with respect to the slow axis of the PM fiber.

Fig. 3. (a) Projection patterns of the transmitted circularly polarized laser light at different powers through a 17.5 cm PM fiber (at room temperature) followed by a rotating polarizer. (b) Ellipticities and angles of the polarization ellipses associated to (a).

Fig. 4. (a) Color-coded transmission of circularly polarized light at different powers through a 17.5 cm PM fiber followed by a rotating polarizer. (b) Transmission versus power of circularly polarized light for the optimum polarizer angle of 58° shown in (a).

Fig. 5. Projection patterns of the transmitted circularly polarized laser light (at 30.4 mW) through a 17.5 cm PM fiber with 6 cm exposed to different temperatures from (a) 2°C to 30°C and (c) 20°C to 20.8°C. (b) and (d) Ellipticities and angles of the polarization ellipses associated to (a) and (c), respectively.

Fig. 6. Transmission of circularly polarized light at 30.4 mW sent to the PM fiber at different temperatures followed by a polarizer oriented at 46°, which is shown by the dashed lines located at 46° in Figs. 3(a) and 3(c). Temperature determination is ambiguous in the highlighted regions. Inset: enlarged scale to show the sensitivity of the temperature sensor.

Fig. 7. (a) Transmission of circularly polarized light at the power of 30.4 mW through the PM fiber at specific temperatures (solid lines), and the transmission of circularly polarized light at specific powers through the PM fiber at temperature of 19°C (circles). (b) Changes in temperature of the PM fiber versus changes in the power of light passing through the fiber calculated from the legend of (a).

Fig. 8. Response curve of the sensor as measured by 1550 nm laser (probe) to a step function change of the 980 nm laser (power/heating source).