Mathematical simulation of fiber optic ring resonator for optical add/drop multiplexing

Abstract

A key device in all optical networks is the optical filter. There are different types of optical filters, for examples, Bragg grating, thin film filter, and arrayed waveguide grating. The use of fiber-optic filters based optical Add/Drop multiplexing (OADM) can process the optical wideband signals in the optical network. In this paper, the designed and simulated filtering characteristics of a serially coupled triple ring optical resonator (STRR) are modeled and investigated. The mathematical relations of the coupling coefficients with the transmission characteristics of the STRR filter are expressed by Z-transform analysis. The transmission spectra of the through port and the drop port of each input of the four-port STRR configuration are simulated. Results are presented on the characteristics of the output as a function of wavelength for various values of the coupling coefficients. With the derived approximate formulas, it is shown that the coupling of the ring fiber system can be changed and thus that the transmission properties of the filter can be controlled and used.