Explosive data generation along with society development in education, health care, scientific research, etc. challenges our current data transmission and processing systems, especially for the servers in data centers which serve as data-relay stations. Benefitting from silicon photonics and fiber optics, fast data routing and transmission with enormous capacity in terms of broad bandwidth can be achieved by silicon photonic chips and optical fibers, respectively. However, optical signals suffer from losses accumulated in on-chip transmission and fiber-chip interface.

In this thesis, we propose the idea of heterogeneously integrated III-V-on-Si microring resonator-based switch matrices to tackle the loss problem mentioned above in existing pure-silicon switches. Because of the indirect-...[ Read more ]

Explosive data generation along with society development in education, health care, scientific research, etc. challenges our current data transmission and processing systems, especially for the servers in data centers which serve as data-relay stations. Benefitting from silicon photonics and fiber optics, fast data routing and transmission with enormous capacity in terms of broad bandwidth can be achieved by silicon photonic chips and optical fibers, respectively. However, optical signals suffer from losses accumulated in on-chip transmission and fiber-chip interface.

In this thesis, we propose the idea of heterogeneously integrated III-V-on-Si microring resonator-based switch matrices to tackle the loss problem mentioned above in existing pure-silicon switches. Because of the indirect-bandgap nature of silicon, silicon platform is not suitable for light emission and signal amplification while III-V materials, such as InP and GaAs, can overcome these limitations. Heterogeneous integration synthesizes both materials onto the same platform to adopt merit of each material. Microring resonator working as a four-port device can route data between the through and drop port which can serve as a single unit in a switch matrix. Unlike traditional broad-band on-chip Mach-Zehnder interferometers (MZIs), microcavity resonators are wavelength-selective which potentially embed wavelength division multiplexing (WDM) into switching scheme and further increase the capacity of an optical switch.

We have designed a III-V-on-Si microring resonator for the single-unit in a switch matrix. Our heterogeneous integration adopts an intermediate layer bonding technique which includes atomic-layer deposited Al₂O₃ as the interfacial layer. Exploiting the free-carrier plasma dispersion effect in III-V materials, we have achieved channel switching between the through and drop ports of the resonator. To further enhance the functionality of the switch, we also explore the ability of photo detection and emission of III-V materials for on-chip power monitoring and signal amplification.