Unidirectional light transmission at telecom wavelengths by polarization-independent diffractive optical element incorporating dual photonic crystal slabs

A polarization-independent diffractive optical element (DOE) consisting of dual photonic crystal (PhC) slabs was proposed for unidirectional light transmission at telecom wavelengths. Employing rigorous coupled wave analysis (RCWA) together with genetic algorithm (GA), the contrast ratios of designed DOE with 10nm precision at normal incidence from opposite directions reached to 33.6 dB and 32.2 dB with transmittance differences of 84.57% and 87.63% at wavelengths of 1310 nm and 1550 nm, respectively. The presented DOE showed great promising for applications in optical communication.