Silicon On-Chip PDM and WDM Technologies Via Plasmonics and Subwavelength Grating

Silicon photonics, which is compatible with standard CMOS technology, is the most promising platform for large-scale photonic integration. The rapid growth of data volume demands larger link capacity and higher integration density of photonic integrated circuits. Multiplexing technology is an effective approach to enhance the capacity of on-chip optical interconnects. This review provides an introduction to the silicon on-chip multiplexing devices using plasmonics and subwavelength grating (SWG). To expand the data transmission capacity, one solution is introducing wavelength-division-multiplexing structures where diplexer and triplexer are fundamental elements. Another is adopting polarization-division-multiplexing (PDM) technology. Polarizer, polarization beam splitter, polarization rotator, polarization beam splitter-rotator, and polarization-independent directional coupler are all essential components for integrated PDM scheme. By using plasmonics and SWG, the mode profile distribution, refractive index, birefringence, and dispersion can all be manipulated, which enables compact devices with high performance.