Novel structure of optical add/drop filters and multi-channel filter based on photonic crystal for using in optical telecommunication devices

In this paper, Using a 2D photonic crystal and a novel square ring resonator, several compact and simple structures have been introduced in the present paper to construct optical add/drop filters and multi-channel filter. The difference structures has been designed and simulated by using the proposed square ring resonator and different dropping waveguides. To do analyses, the finite-difference time-domain method and the plane wave expansion have been used. The three add/drop filters can separate the wavelength of 1554 nm with a transmission coefficient of 100 %, quality factor of 1295 and bandwidth of 1.2 nm. The models of structures are simulated by the RSOFT CADLayout software. The results, flexibility and simplicity of structures have caused from their used to designing of an optical multi-channel filter with a channel spacing of 1.5 nm. The advantages of this design include the channel spacing, quality factor, transmission coefficient and bandwidth which are suitable for applicability in optical communication systems such as wavelength division multiplexing systems.