High Q-factor plasmonic filter based on MIM structures and its application in the design of a dual band demultiplexer for optical communication wavelengths

One of the key components in optical integrated circuits is bandpass filters. In this article, a scheme of plasmonic filters consisting of a nanodisk cavity coupled with two T-shaped metal-insulator-metal (MIM) waveguides is presented. The nanodisk cavity is in a square or rectangular shape. The effects of the geometrical parameters variations on the transmission spectrum are investigated. The results of the numerical simulation analysis indicate that the perfect transmission peak can be achieved by optimizing the structure parameters. Hence, the appropriate dimensions of this structure for operating in the optical communication wavelength range (from O to L bands) are obtained. Also, the proposed filter exhibits the transmission peak of 0.99 and the high quality factors ( Q-factors) of 91 and 109.25 at the wavelengths of 1550 nm and 1310 nm, respectively. In addition, a design of two-channel demultiplexer is presented, in which the waveguides are connected by T or Y junctions. The results show that the proposed structure exhibits the transmission peaks of 0.8 and 0.67 and the Q-factors of 65 and 103.3 at the resonance wavelengths of1310 nm and 1550 nm, respectively. (C) 2021 Optical Society of America