Ultra-large Angle Curved Reflectors and Their Applications to Passive and Active Photonic Integrated Circuit Devices

Nanoscale optical components such as waveguides, resonators are the building blocks of integrated optical networks. With the advent of nano-fabrication technologies we are able to realize such components in strongly confined sub-micron dimensions. A photonic integrated circuit (PIC) that contains these components integrates multiple photonic functions on a single chip. Traditionally, functionality of PIC is realized via modification of waveguide structure. on the contrary, reflective components such as curved reflectors propagate light in two dimensional free space thence have many advantages over their refractive counterparts such as tighter space requirement, more flexibility, and lower loss. In this work, we propose curved reflector as an essential component to realize multiple integrated functions in PICs. These functions include spot size conversion, beam turning, waveguide crossing, etc. Waveguide taper, bended waveguide, direct waveguide crossing are the conventional counterparts to realize such functions. In particular, we proposed and realized photonic integrated interconnections using curved reflectors and curved reflector semiconductor optical amplifier (CR-SOA).;In this thesis, theoretically analysis of curved reflectors is introduced and discussed in depth. Gaussian beam analysis, in particular, Hermite-Gaussian beam analysis is used to explain light propagation and distortion in interaction with curved reflectors. Theoretical formulation of beam propagation in presence of curved reflector is verified with Finite-Difference Time-Domain (FDTD) method. General design strategies of curved reflectors are proposed. Multiple applications of curved reflector in passive and active devices are introduced. Distortions induced in light beams by curved reflectors, its original, theoretical description, and compensation methods are discussed in details as well.;Photonic integrated interconnection based on silicon-on-insulator (SOI) platform and curved reflector semiconductor optical amplifier (CR-SOA) based on InGaAsP platform, their design, fabrication, and testing are discussed in details. Design of Photonic integrated interconnection makes use of curved reflector to focus or collimated light beams so as to realize waveguide turning, offsetting, and crossing. Design of CR-SOA takes advantage of the capability of curved reflectors to expand light beam in extreme tight space to realize large area amplification and compact device footprint. Major nano-fabrication processes that are used in developing designed devices are introduced and discussed. Lithography and dry etching are two common processes in pattern defining. Quantum well intermixing is utilized for convenient integration of passive active devices. Other nano-fabrication techniques involved are also discussed. Lastly, we present various testing techniques as well as their theoretical background. We focus on discussion of testing curved reflector semiconductor optical amplifier (CR-SOA). Techniques to improve characterization of CR-SOA such as cooling stage and pulsed large current source are introduced. Measurement results are presented and discussed in details.