TEMPERATURE-DEPENDENCE OF PYROLYZED SOL-GEL PLANAR WAVE-GUIDE PARAMETERS

A set-up for varying the temperature (5-90-degrees-C) of planar optica l waveguides useful in sensing applications is described. The principl e is to control the temperature of the cover medium (in this case wate r). The propagation constants of guided modes are measured via a grati ng coupler. Only that part of the waveguide in the immediate vicinity of the incoming external light beam is heated or cooled. The temperatu re coefficients of the thickness and refractive index of the waveguide material can be described by simple polynomial expressions.