1 x 4 optical demultiplexer of the second band in a hole-type silicon photonic crystal

A 1x4 optical demultiplexer (OD) based on the self-collimation (SC) effect in hole-type silicon photonic crystal (PC) was proposed, and its performance was numerically demonstrated. The 1x4 OD consists of two cascaded Mach-Zehnder interferometers and an independent mirror. It has a total of four splitters and five mirrors. The simulation results indicate that by selecting the correct optical path length, the input SC beam with four evenly spaced frequencies can be demultiplexed into four output ports in the 1x4 OD. If the center working wavelength is 1550 nm, the free spectral range of the 1x4 OD is about 23 nm, which almost covers the whole optical communication C-band window. The size of the structure is on the order of 50 mu m. Because of its simple structure, small size, and single material, it has potential application value in future photonic integrated circuits. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)