S. Saini et al., TEMPERATURE-DEPENDENCE OF PYROLYZED SOL-GEL PLANAR WAVE-GUIDE PARAMETERS, Journal of physics. D, Applied physics, 27(6), 1994, pp. 1134-1138
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.