Executive Summary : | With the increase in the high data link capacity demand, interconnects with large bandwidth have been the prime requirement to communicate between on-chip and off-chip components. However, traditionally using electrical interconnects face major drawbacks of having high power dissipation and increase in propagation delay as the down scaling of the minimum feature size of the integrated circuits. A promising solution to this problem is using optical interconnects and increasing its link capacity to accommodate as many data channels as possible. Optical multiplexing is an efficient way to increase the bandwidth density of optical communication systems. Wavelength Division Multiplexing (WDM) is the most widely used technique which enables multiplexing of different channels using multiple laser sources with different wavelengths. Moreover, Mode Division Multiplexing (MDM) and Polarization Division Multiplexing (PDM) schemes have recently emerged that allow transmitting multiple channels using different modes and different polarizations respectively within the same wavelength. By combining these individual optical multiplexing techniques, hybrid multiplexing technology can be realized to further increase the bandwidth capacity with data rates up to Peta-bits per second, without increasing the number of components and chip area. Furthermore, conventional optical multiplexers suffer from large footprint, making them not suitable for ultra-dense optical circuits. A unique dielectric structure, called Photonic Crystals (PhCs) has the potential use in the field of ultra-compact devices for Photonic Integrated Circuits (PICs) due to its capability of molding light at wavelength scale with excellent optical properties like high optical confinement, negligible bending loss, etc. To design and fabrication of 2D PhC devices to increase the datalink capacity with compact device size for multiplexing applications in datacenters is proposed in this project. By engineering the defects in 2D PhCs, various PhC components such as, waveguides, resonant cavities, bends, splitters, filters etc. are possible to fabricate, leading to the possibility of replacing millimeter scale devices with micro scale devices in WDM systems. However, PhC multiplexers with improved performance metrics for ultra-dense integration with high fabrication tolerance for practical applications is still challenging, and this opens for more research scope in this field. Moreover, PhC multiplexing devices reported so far are mainly based on WDM. Therefore, it is vital to extend more research scope for other hybrid multiplexing mechanisms. |