Optical waveguide arrays induced in fused silica by void-like defects using femtosecond laser pulses

We report a new approach to the microfabrication of permanent optical waveguide arrays inside fused silica induced by focusing infrared femtosecond laser pulses with microjoule energy. These arrays consist of waveguides limited by void-like damage zones with very loose coupling among adjacent guides, thus allowing the excitation of a single one. The proposed method shows the possibility of using created void-like structures for both the fabrication of integrated optical devices as well as for the control of previously induced refractive index change regions. PACS 42.65.Re; 42.82.Et; 42.79.-e