Fig. 1. Schematic configuration of the proposed on-chip PC. (a) Top view; (b) waveguide cross section of PS #1 and PS #3; (c) waveguide cross section of PS #2.

Fig. 2. Calculated output transmissions [ax′2,ay′2,δ′] for the launched light with different [ax2,ay2,δ0]. (a), (d), (g) show the normalized power ax′2 and ay′2; (b), (e), (h) show the phase difference δ′; (c), (f), (i) show recorded Poincaré sphere when scanning φ2 and φ3. Here, one chooses [ax2,ay2,δ0]=[1,0,0] for (a)–(c), [ax2,ay2,δ0]=[1/2,1/2,0] for (d)–(f), [ax2,ay2,δ0]=[1/4,3/4,π/4] for (g)–(i), respectively.

Fig. 3. (a) Simulated TE0 and TM0 mode field profiles of the fully etched silicon photonic waveguide; (b) calculated effective thermo-optic coefficients dNeff/dT for the TE0 and TM0 modes, and the difference between their thermo-optic coefficients.

Fig. 4. (a) Calculated effective indices of the TE0, TM0, and TE1 modes of the bilevel ridge waveguide as the core width varies. Simulated light propagation in the designed PDMC when the (b) TM0 mode and the (c) TE0 mode are launched.

Fig. 5. Light propagation at the regions of PS #1, PDMC1, and DMPS #1 for (a) the TE0 mode, (b) the TM0 mode, and the 45° linearly polarized light under different δ; (c) δ=2mπ; (d) δ=2mπ+π; (e) δ=2mπ±0.5π (at 1550 nm).

Fig. 6. Light propagation for the two TE0 modes launched into the two arms of the MZI, when (a) φ2=0; (b) φ2=π; (c) φ2=0.5π.

Fig. 7. (a) Optical micrographs of the fabricated PC; (b) enlarged view for the polarization converter; (c) SEM of the DMPS.

Fig. 8. Experiment setup for characterizing the polarization converter. ASE, amplified spontaneous emission; PC, fiber polarization controller; MVS, multichannel voltage source; PBS, fiber polarization beam splitter; OSA, optical spectrum analyzer.

Fig. 9. Measured transmissions at Port #1 and Port #2 of the PC when the (a), (b) TE0 and (c), (d) TM0 modes are, respectively, input; (a), (c) φ2=0; (b), (d) φ2=π.

Fig. 10. Experiment setup for observing the output mode field. TL, tunable laser; PC, polarization controller; MVS, multichannel voltage source; QWP, quarter-wave plate; Pol., polarizer; CCD, charge coupled device.

Fig. 11. Captured output mode field for the generated SOP at 1550 nm. (a) TM0 mode generation from the launched TE0 mode; (b) TE0 mode generation from the launched TM0 mode; (c) circularly polarized light generation from the launched TE0 mode. The arrows indicate the axis of the polarizer.

Fig. 12. Measured SOP on the Poincaré sphere for (a) the input TE0 mode, (b) the input TM0 mode, and (c) a ∼45° linearly polarized light beam. In (a) and (b), P2 was fixed at different steps, and for each P2, a sweep of the P3 was performed. In (c), the P1,P2, and P3 were swept simultaneously, thus producing ∼6000 points traversing the entire Poincaré sphere. (d) The measured PER range for the launched TE0 mode operating with different wavelengths.

Table 1. Performance Metrics Comparison of the Representative PCs