An Ultracompact Silicon Triplexer Based on Cascaded Bent Directional Couplers

A novel on-chip triplexer based on bent directional couplers has been demonstrated to separate the 1310 nm wavelength band (~100 nm wide bandwidth) into one port and 1490 and 1550 nm wavelength bands into the other two ports. By utilizing bent directional couplers, the footprint of the total device can be reduced to 19 × 31 μm2, which is an ultracompact triplexer with high performance ever demonstrated. The simulated high-performance device, easily fabricated with only one fully etching step, is also characterized with low crosstalk (~-15 dB) and <;1 dB insertion loss.