Temperature-independent silicon waveguide optical filter

We have proposed a new design for temperature-independent silicon optical filters utilizing a combination of wide and narrow waveguides. The waveguide structure was optimized to minimize the spectral shift of the filter owing to the environmental temperature change. Based on this new waveguide design, we fabricated Mach-Zehnder interferometer optical filters on silicon-on-insulator substrates. The measured spectrum showed substantially small temperature dependence being in good agreement with the theoretical estimation.