Compact and Broadband Optical Add-Drop De-Multiplexer With Cascaded Elliptical Micro-Rings on SOI

We demonstrate a four-channel de-multiplexer based on third-order cascaded elliptical micro-rings on silicon-on-insulator. By applying cascaded elliptical micro-rings structure, the fabrication tolerance was released. The spectral responses of four drop-ports over the S, C, and L bands (1450-1630 nm) were measured, which showed an enhanced performance. The four-channel de-multiplexer has box-like transmission spectra with an ultra-wide 3 dB bandwidth of about 2.6 nm, high out-of-band rejection ratio of more than 40 dB, low-channel cross talk of about -38 dB, small footprint of about 0.0012 mm 2 , and large operational spectral range of more than 180 nm. The de-multiplexer can support high-data-rate signal transmission capacity.