Fig. 1. Schematic configuration of the 2×2 MPSS for two modes and two polarizations. As an example, the TE0 and TE1 channels of Input 1 and the TM0 and TM1 channels of Input 2 are routed to Output 1 and other channels are routed to Output 2. The calculated mode patterns of the TE0, TE1, TM0, and TM1 modes are intensity profiles. The intensity profiles of the TM0 and TM1 modes look like second-order TM modes in the normal direction. It is attributed to the small height (220 nm) of the silicon waveguides.

Fig. 2. Basic elements of the 2×2 MPSS. (a) A PBS and a mode multiplexer; (b) a waveguide crossing; (c) a 1×2 MMI; (d) an MZI switch.

Fig. 3. (a) Microscope photo of a fabricated MPSS chip. (b) Magnified SEM images and microscope photos of a PBS, a mode multiplexer, waveguide crossings, and an MZI switch.

Fig. 4. Measured inter-modal crosstalk performance.

Fig. 5. Measured intra-modal crosstalk performance.

Table 1. Measured Performance of Building Blocks