This invention describes how commercial silicon-on-insulator material can be used to
fabricate both wavelength filters and wavelength-selective photodetectors. The silicon-on-
insulator substrates have a buried silicon dioxide layer and a thin top silicon layer and are
manufactured for high speed electonics applications. However, in this invention, the thin
silicon layer is used as the core of a waveguide and the buried silicon dioxide as a lower
cladding region. Another cladding layer and a low index waveguide is fabricated on the …