Fabrication of distributed feeback devices using X-ray lithography

Distributed feedback structures are essential for many applications in optics where wavelength-selectivity is required. This thesis focuses on the development of nanofabrication techniques for the fabrication of distributed feedback devices for optical communications. The distributed feedback laser and Bragg-grating-based optical filters single-pole, multiple-pole and integrated resonant channel-dropping filters are technology drivers to demonstrate these nanofabrication techniques. A combination of holographic, spatial-phase-locked electron-beam lithography and x-ray lithography is used to fabricate the necessary phase-coherent grating structures. A laterally-coupled distributed-feedback laser is proposed which offers the potential for simpler processing and consequently higher yields. Computer simulations are performed which indicate that such a device structure provides sufficient coupling for laser action. A novel technique based on ion implantation is developed for patterning lateral gratings on deep ridge waveguides. Finally, high-quality single-pole, quarter-wave-shifted Bragg resonators, the building block of the integrated resonant channel-dropping filter, are fabricated in a silica-on-silicon materials system using a self-aligned process and stepand-repeat x-ray lithography. The first demonstration of multiple-pole optical filters is also presented. Thesis Supervisor: Henry I. Smith Title: Joseph F. and Nancy P. Keithley Professor of Electrical Engineering Thesis Reader: Hermann A. Haus Title: Institute Professor, Professor of Electrical Engineering Thesis Reader: Clifton G. Fonstad Title: Professor of Electrical Engineering