On-Chip Silicon Triplexer Based on Asymmetrical Directional Couplers

We propose and demonstrate an on-chip silicon triplexer with a compact footprint and high performance. The asymmetrical directional couplers (ADCs) are used as wavelength filters in the proposed triplexer. By carefully designing the phase mismatch and coupling strength for each asymmetrical directional coupler, the three wavelengths are separated and coupled into different output ports. The measured excess losses are less than 1 dB for all the three channels. The 3-dB bandwidths are 70, 30, and 20 nm for the three output ports (1.31, 1.49, and 1.55 mu m), respectively. The total length of the ADC-based triplexer is similar to 150 mu m.