Double groove silicon grating polarizer in telecommunication wavelength band

In this paper, we propose an ultra broad band polarizer operating in the telecommunication wavelength band, this device consisting a double groove silicon grating is designed with using the inverse mathematical method and rigorous vector diffraction theory. It is shown from our calculations that the device presents extremely high reflection (R>95%) for TE polarization light and high transmission (T>95%) for TM polarization over similar to 400 nm wavelength range, moreover, the extinction ratio is similar to 30 in the central wavelength 1550 nm. Furthermore, it is found with rigorous coupled wave analysis (RCWA) that the extremely wide band property for TE polarization is due to the excitation of strong modulation guided modes in the design wavelength range. (C) 2014 Elsevier GmbH. All rights reserved