Highly tunable Terahertz filter with magneto-optical Bragg grating formed in semiconductor-insulator-semiconductor waveguides

A highly tunable terahertz (THz) filter with magneto-optical Bragg grating formed in semiconductor-insulator-semiconductor waveguides is proposed and demonstrated numerically by means of the Finite Element Method. The results reveal that a sharp peak with high Q-value presents in the band gap of Bragg grating waveguide with a defect, and the position of the sharp peak can be modified greatly by changing the intensity of the transverse magnetic field applied to the device. Compared to the situation without magnetic field applied, the shift of the filtered frequency (wavelength) reaches up to 36.1 GHz (11.4 μm) when 1 T magnetic field is applied. In addition, a simple model to predict the filtered frequency and an effective way to improve the Q-value of the filter are proposed by this paper.