A novel tunable optical add-drop multiplexer based on a silicon forward or backward directional coupler is proposed. This device enables one wavelength channel or a small band of channels to be inserted into or extracted from a wavelenghth-division multiplexing (WDM) signal with the capability that the wavelength for which this occurs can be varied utilizing injection current variation. For the backward coupling configuration, an adjacent sidelobe level rejection of –7.5 dB, coupling efficiency of 96.13%, and a 3-dB bandwidth of 0.174 nm with central wavelength at 1549.93 nm are simulated. 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 n of 0.0021. The forward coupling configuration provides a somewhat wider 3-dB bandwidth and more extensive tuning capability.

Date Published: 1 May 2006
PDF: 5 pages
Opt. Eng. 45(5) 054603 doi: 10.1117/1.2205831
Published in: Optical Engineering Volume 45, Issue 5