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Degraded Performance of Photonic Crystal Couplers due to Fabrication Imperfections

The influence of fabrication imperfections on the performance of photonic crystal directional couplers (PCDC) with different structure parameters were investigated theoretically. It was found that the air hole position misalignment perpendicular to the waveguide has a more powerful influence on the transmission efficiency of PCDC than other fabrication imperfection factors, and reducing r/a is helpful to improve the robustness of PCDC.