Integrated high-repetition-rate femtosecond lasers at 1.55 [mu]m

Abstract

Performance of state-of-the-art, electronic analog-to-digital converters is currently limited by the 100-fs aperture jitter. However, optical sampling can overcome the jitter limit by using femtosecond lasers that have jitter as low as 100 as, which is a three orders of magnitude improvement when compared to electronics. Currently, most of these lasers exist as bulk or fiber lasers. While such configurations can provide flexibility in order to tailor the behavior of the lasers to specific needs, they are usually as expensive as $10,000 to $100,000 and require precisely adjustable mounts and high-quality optical components. To realize the possibility of femtosecond lasers replacing current electronics for unprecedented performance in the future, these lasers must be as compact, robust, and affordable as electronic circuits. A monolithically integrated mode-locked laser can lower the cost of building such femtosecond lasers and, at the same time, make them less vulnerable to environmental perturbation. This can be achieved by mass-producing them with less expensive materials such as silicon, silicon oxide, or compatible materials. Since all necessary optical components are integrated monolithically on a silicon substrate, bulky and expensive high-precision discrete components can be excluded. The goal of this thesis is the development of femtosecond lasers that can overcome the limit of electronics and potentially replace them. Possible approaches and current achievements are discussed towards this goal.