Compact Optical Add-Drop De-Multiplexers with Cascaded Micro-Ring Resonators on SOI**Supported by the National High Technology Research and Development Program of China under Grant No 2015AA016904, the National Key Research and Development Plan of China under Grant No 2016YFB0402502, and the National Natural Science Foundation of China under Grant No 61275065.

Abstract

A four-channel integrated optical wavelength de-multiplexer is experimentally illustrated on a silicon-on-insulator (SOI) substrate. With the aid of cascaded micro-ring resonators, the whole performance of the wavelength de-multiplexer is improved, such as 3 dB bandwidth and channel crosstalk. Based on the transform matrix theory, a four-channel wavelength de-multiplexer with average channel spacing 4.5±0.5 nm (3 dB bandwidth ∼ 2 ± 0.5 nm) is demonstrated at telecommunication bands. For each channel, the extinction at the adjacent channel is below −39 dB and the out-of-band rejection ratio is up to 40 dB. The channel dropping loss is below 5 dB in the five FSR spectral response periods (near 100 nm).