Photonic crystal three wavelength division multiplexing based on multimode interference theory

This paper presents a two-dimension photonic crystal triplexer wavelength division multiplexing based on multimode interference theory with 131 μm, l.49μm, and 1-55 μm. According to self-imaging multimode interference effect, the guided modes transmitted in multimode waveguides have different phase shifts due to different propagation constants and thus have different space output fields. When intrinsic mode dispersion curves intersect at one point, the Interference is disappeared at this wavelength. Energy is restricted in the original incident waveguide. This paper realizes three wavelengths division by two cascades. The insertion loss, extinction ratios, and power distribution have been demonstrated by the plane wave expansion method and finite different time domain method. Performance parameters are optimized through structural improvement. This device is not subject to electromagnetic interference and has a small size easy to integrate.