AbstractsEngineering

A novel tunable optical add-drop multiplexer (OADM) based on a silicon forward/backward directional coupler is proposed. This device allows one wavelength channel or a small band of channels to be inserted into or extracted from a WDM signal with the capability that the wavelength for which this occurs can be varied utilizing injection current variation. The modeling for the proposed tunable OADM based on the forward/backward grating-assisted directional coupler (GADC) predicts that dense 50 GHz channel spacing dense wavelength-division multiplexing (DWDM) signals could be selected with 23.5/15.9 nm (forward/cascaded forward) or 0.174 nm (backward) bandwidth with reasonably high side lobe level rejection. Modulation in silicon is produced by a carrier concentration-induced change in the refractive index. Carrier injection or depletion can produce the required negative or positive refractive index change. Wavelength tunability of 169.3 nm (forward coupling) or 0.78 nm (backward coupling) result from our simulations, corresponding to a voltage-induced refractive index change of 0.0021.