SILICA-WAVE-GUIDE THERMOOPTIC PHASE-SHIFTER WITH LOW-POWER CONSUMPTION AND LOW LATERAL HEAT DIFFUSION

A thermooptic (TO) phase shifter consisting of a thin film heater on t he top of a loaded stripline silica waveguide on a silicon substrate i s shown to exhibit faster time response than reported for phase shifte rs based on a buried silica waveguide configuration. The rise time was measured to be 0.24 ms, which is in good agreement with calculated th ermal distributions in the structures. The lateral heat diffusion dist ance in the loaded stripline structure is shown to be smaller than in buried waveguide structures. This implies small thermal crosstalk and suggests a high-level integration of adjacent waveguides.