Effect of sidelobes on demultiplexing characteristics of a grating-folded directional coupler demultiplexer

The effect of sidelobes on the demultiplexing characteristics of a grating-folded directional coupler demultiplexer are investigated. The bit error-rate characteristics of the demultiplexed signal is examined, and a power penalty originated from the sidelobe is observed for the grating-folded directional coupler with conventional uniform grating. A phase-synchronized sampled grating is applied to suppress the sidelobe of a Bragg grating, and power-penalty-free demultiplexing is achieved in this structure.