A thermo-optic lens of the present invention includes a plurality of parallel heating elements having substantially constant center-to-center spacing and respective dimensions varying from the outermost heating elements to the innermost heating elements, and at least two conductive elements for providing a potential across the heating elements. The dimensions of the heating elements are varied such that a parabolic temperature distribution is generated within the thermo-optic lens. A dispersion compensator of the present invention includes a first and a second waveguide grating, each of the waveguide gratings having a first star coupler, an array of waveguides of increasing path lengths, a first end of each of the waveguides of the array of waveguides optically coupled to the first star coupler, and a second star coupler, a second end of each of the waveguides of the array of waveguides optically coupled to the second star coupler. The dispersion compensator further includes a lens having a parabolic refractive index distribution, the lens optically coupling the second star coupler of the first waveguide grating and the second star coupler of the second waveguide grating.