Femtosecond Laser Microfabrication and Packaging of Integrated Optical Components

Harvard University, Cambridge MA

Investigators

Abstract

The dynamic nature of future optical networks requires high levels of integration, fast response times, and adaptability of the optical components. Laser micromachining circumvents the limitations of planar integration, making three-dimensional integration possible and allowing dense packaging of optical devices. Femtosecond micromachining is material independent, allowing devices to be manufactured in any transparent substrate. Oscillator-only machining has several advantages over amplified femtosecond laser machining: easy control over the size of the structures without changing focusing, polarization-independent structures, lower initial investment cost and higher-speed manufacturing. These advantages make oscillator-only machining feasible for commercial applications, and the group is working on a number of integrated optical devices with immediate industrial applications. By controlling the cross-sectional size of the waveguides, the group will produce periodically modulated waveguides that can serve as Bragg gratings. By controlling the three-dimensional geometry of waveguides written into an electro-optic material, they will manufacture cascaded Mach Zehnder filters capable of dynamic filtering of optical signals. Applying this technique to magneto-optical materials, they will manufacture monolithic Faraday isolators. By selecting a rare-earth doped glass substrate, they will produce an integrated amplifier. This technique provides one of the first viable fabrication technologies for three-dimensional integrated optics. In addition to producing a number of commercially viable integrated optical components, the proposed research will contribute to the understanding of the interaction between intense laser fields and transparent materials. The results from this proposed work are therefore directly relevant to materials science, plasma physics, and applications of short laser pulses in biological studies and laser microsurgery. The members of the group, nearly half of which are female, are also heavily involved in a number of outreach and education programs, extending the impact of the research beyond the university to K-12 students, teachers, and the general public.