The scientific goal of the present research project consists of the theoretical and experimental development of processes for tunable frequency conversion and time delay of guided light signals in Silicon-on-Insulator (SOI) structures. The processes used here are called dynamic in the literature, meaning that the manipulation of the light signal takes place while it is still confined to the photonic structure. The desired effects are achieved by an ultrafast change of the refractive index in the guiding structure.

A frequency shift by about 100GHz is intended to be realized. This process is based on shifting the resonance frequency of a photonic crystal cavity or the frequency position of the guided mode of a line defect waveguide. Approaches for achieving time delays of about 100ps should be investigated. Investigated structures are photonic crystal cavities and line defect waveguides.

In 2009 air-bridge photonic crystal heterostructure cavities with high Q-factors of up to 25000 have been fabricated. However theoretical investigations have led to the conclusion that resonant structures only allow for 50% of a light signal¿s energy to be dynamically manipulated. On the contrary, line defect waveguides theoretically allow for 100% efficiency of the dynamic conversion process. Simple methods for engineering the group velocity of the guided mode of a line defect waveguide have been implemented to design a theoretically working light-storage device. Experimentally a group index of 25 over a bandwidth of 700GHz has been determined in an 80µm long line defect waveguide.

Wissenschaftliche Kontakte und Kooperationen

• Prof. Dr. Ernst Brinkmeyer, TUHH, Optische Kommunikationstechnik
• Prof. Dr.-Ing. habil Jörg Müller, TUHH, Mikrosystemtechnik
• Prof. Dr. Klaus Petermann und Dr. Jürgen Bruns, TU Berlin, Hochfrequenztechnik/Photonik
• Prof. Dr. Thomas F. Krauss, U. St. Andrews, School of Physics and Astronomy

The scientific goal of the present research project consists of the theoretical and experimental development of processes for tunable frequency conversion and time delay of guided light signals in Silicon-on-Insulator (SOI) structures. The processes used here are called dynamic in the literature, meaning that the manipulation of the light signal takes place while it is still confined to the photonic structure. The desired effects are achieved by an ultrafast change of the refractive index in the guiding structure.

A frequency shift by about 100GHz is intended to be realized. This process is based on shifting the resonance frequency of a photonic crystal cavity or the frequency position of the guided mode of a line defect waveguide. Approaches for achieving time delays of about 100ps should be investigated. Investigated structures are photonic crystal cavities and line defect waveguides.

In 2009 air-bridge photonic crystal heterostructure cavities with high Q-factors of up to 25000 have been fabricated. However theoretical investigations have led to the conclusion that resonant structures only allow for 50% of a light signal¿s energy to be dynamically manipulated. On the contrary, line defect waveguides theoretically allow for 100% efficiency of the dynamic conversion process. Simple methods for engineering the group velocity of the guided mode of a line defect waveguide have been implemented to design a theoretically working light-storage device. Experimentally a group index of 25 over a bandwidth of 700GHz has been determined in an 80µm long line defect waveguide.

Wissenschaftliche Kontakte und Kooperationen

• Prof. Dr. Ernst Brinkmeyer, TUHH, Optische Kommunikationstechnik
• Prof. Dr.-Ing. habil Jörg Müller, TUHH, Mikrosystemtechnik
• Prof. Dr. Klaus Petermann und Dr. Jürgen Bruns, TU Berlin, Hochfrequenztechnik/Photonik
• Prof. Dr. Thomas F. Krauss, U. St. Andrews, School of Physics and Astronomy