Wavelength Division Demultiplexing and Crosstalk Assessment of a Photonic Crystal Filter

We report on the design, fabrication, and characterization of a filter for demultiplexing in the wavelength division domain achieved with a H0 cavity on a III-V photonic crystal (PhC) membrane. This device is single mode, the total insertion losses are about 10.5 dB, the drop efficiency is close to 40%, and the channel isolation can exceed 20 dB at 500 GHz. A 28-Gb/s nonreturn to zero (NRZ) wavelength demultiplexing shows <; 0.5-dB penalties. Crosstalk measurements demonstrate <; 1-dB penalty when adjacent channels are spaced as closely as 235 GHz, demonstrating that this filter has good compatibility with LAN-wavelength division multiplexing. Finally, a 56-Gb/s NRZ-differential quadrature phase-shift keying signal filtering is assessed, revealing a negligible penalty of ( <; 0.5 dB).