Weighted distributed feedback structure for all-optical bistable devices

We proposed to use a distributed feedback structure with a weighted coupling coefficient (W-DFB) in an all-optical bistable device in order to improve on-state transmittance and to reduce threshold intensity. Through numerical calculations, characteristics of the W-DFB structure were discussed compared with those of a conventional DFB structure. The W-DFB optical bistable device exhibits high on-state transmittance and low-threshold input intensity. Fabrication of the W-DFB structure with a periodicity of 169.8 Ma is demonstrated on a CdSxSe1-x-doped glass substrate by means of holographic exposure with a double-coated photoresist and reactive ion etching in CHF3.