Fig. 1. Ray tracing in circular fiber

Fig. 2. Flow chart of single ray tracing in fiber

Fig. 3. Geometry of simulation

Fig. 4. Near filed outputs under different input deviations d/R. (a) Circular fiber, d/R=0; (b) circular fiber, d/R=0.4; (c) circular fiber, d/R=0.8; (d) octagonal fiber, d/R=0; (e) octagonal fiber, d/R=0.4; (f) octagonal fiber, d/R=0.8

Fig. 5. Projection of single skew ray propagation trajectory at end face. (a) Circular fiber; (b) octagonal fiber

Fig. 6. Far field patterns. (a)(d)(g) Input; (b)(e)(h) output of octagonal fiber; (c)(f)(i) output of circular fiber

Fig. 7. Double-fiber scrambler based on ball lens. (a) Structure of double-fiber scrambler; (b) ball lens used for exchanging far and near fields

Fig. 8. Near field patterns outputted by double-fiber scrambler. (a) Circular fiber, circular input pupil, d/R=0.4; (b) circular fiber, circular input pupil, d/R=0.8; (c) circular fiber, ring input pupil, d/R=0.4; (d) circular fiber, ring input pupil, d/R=0.8; (e) octagonal fiber, circular input pupil, d/R=0.4; (f) octagonal fiber, circular input pupil, d/R=0.8; (g) octagonal fiber, ring input pupil, d/R=0.4; (h) octagonal fiber, ring input pupil, d/R=0.8

Fig. 9. Far field patterns outputted by double-fiber scrambler. (a) Circular fiber, circular input pupil, d/R=0.4; (b) circular fiber, circular input pupil, d/R=0.8; (c) circular fiber, ring input pupil, d/R=0.4; (d) circular fiber, ring input pupil, d/R=0.8; (e) octagonal fiber, circular input pupil, d/R=0.4; (f) octagonal fiber, circular input pupil, d/R=0.8; (g) octagonal fiber, ring input pupil, d/R=0.4; (h) octagonal fiber, ring input pupil, d/R=0.8