Fig. 1. Basic optical characteristics of TYDSF. (a) Refractive index distribution (RID) of TYDSF (the inset is the profile of the TYDSF observed under a microscope). (b) Attenuation spectrum of TYDSF. (c) Excitation and emission spectra of TYDSF.

Fig. 2. Schematic diagram of the annealing process and the linear birefringence measurement of TYDSF. (a) Schematic diagram of TYDSF annealing. (b) Schematic diagram of microscope birefringence measurement instrument. (c) Picture of TYDSF samples for linear birefringence measurement.

Fig. 3. Measurement system of state of polarization and Faraday rotation for optical fibers.

Fig. 4. Retardance curves in four directions of TYDSF samples (a) without annealing and annealed at (b) 350°C, (c) 450°C, (d) 550°C, (e) 650°C, (f) 750°C, (g) 850°C, (h) 950°C (the insets on the left are the retardance distributions and color maps. The insets on the right are the intensity distributions).

Fig. 5. Output polarization state of TYDSF with the length of a quarter beat length. (a) Schematic diagram of the transformation of linearly polarized light into right-handed and left-handed circularly polarized light in a fiber quarter-wave plate; (b) evolution of azimuth and ellipticity of the output state of polarization versus the input azimuth in a fiber quarter-wave plate.

Fig. 6. Faraday rotation of fiber samples. (a) Faraday rotation of SF at 808, 980, and 1310 nm; Faraday rotation and compensated value (F · L) of TYDSF at (b) 808 nm, (c) 980 nm, and (d) 1310 nm.

Fig. 7. Verdet constants of SF and TYDSF at 808, 980, and 1310 nm.

Table 1. Linear Birefringence of TYDSF after Annealing at Different Temperatures

Table 2. Average F · L of TYDSF before and after Annealing at 808, 980, and 1310 nm