Design of Tunable Multiple- Cavity Filter for Optical Fiber Communication

Abstract

In this paper a new type of cavity filter is investigated. The device is based on a Fabry–Perot interferometer which employing a cavity and two dielectric Bragg mirrors. The cavity filter uses multi layers of ( ) and (ZnS) to produce a multi -layers ZnS/ cavity filter operating in the center wavelength of 1550 (nm). Zinc sulfide is used in this paper due to its high refractive index, while due to its low refractive index material. The filter is to be coated on Fused Silica having the index of 1.55 and operates at normal incidence. The ZnS/ thin film structure was designed using the Thin Film Design software (TF Calc). The simulation results show that the transmittance of the ZnS/ filter is about 95% for central wavelength of 1550 nm. This filter is essential for monitoring and reconfiguring optical networks.