“…Signi cant attempts have been made to study the theoretical and experimental properties of optical devices based on photonic crystal couplers with the aim of achieving shorter coupling lengths and improved performance [4][5][6][7]. Photonic crystal couplers play a crucial role in many optical communication systems such as optical logic gates [8,9] ,optical splitter [10,11] ,optical switches [12][13][14],sensors [15,16], lters [17,18],and demultiplexers [19][20][21][22]. These devices provide advantages such as reduced crosstalk, compact size and high e ciency.…”