A new way of uniform splitting of the optical power by directional coupling between the photonic crystal waveguides

Directional coupler can be constructed by putting multiple photonic crystal waveguides together. The propagation of the optical field entering this system symmetrically was analysed numerically according to self-imaging principle. On the basis of this structure, ultracompact multiway beam splitter was designed and the ones with three and four output channels were discussed in details as examples. By simply tuning the effective refractive index of two dielectric rods in the coupler symmetrically to induce the redistribution of the power of the optical field, uniform or free splitting can be achieved. Compared with the reported results, this way is simpler, more feasible and more efficient and has extensive practical value in future photonic integrated circuits.

Open Project of the State Key Laboratory on Integrated Optoelectronics of Institute of Semiconductors, Chinese Academy of Sciences Research Project from Department of Education of Jiangxi Province, China 2007-59 GJJ08066 Natural Science Foundation of Jiangxi Province, China 2008GZW0006 2007GQW2057 Project supported by the Open Project of the State Key Laboratory on Integrated Optoelectronics of Institute of Semiconductors, Chinese Academy of Sciences, the Research Project from Department of Education of Jiangxi Province, China (Grant Nos. 2007-59, GJJ08066), and the Natural Science Foundation of Jiangxi Province, China (Grant Nos. 2008GZW0006,2007GQW2057).