Analysis of Optical Ring Resonator Add/Drop Filters
Riyadh D. Mansoor, Hugh Sasse, Alistair P. Duffy
1st January 0001
Add/drop filter, Free spectral range, Ring resonator, Silicon on insulator, Wavelength division multiplexing
Ring resonators are key components in modern optical networks. Their size allows high density integration in optical photonic circuits due to the use of high index contrast material and the availability of CMOS fabrication facilities. Ring resonator based filters in wavelength division multiplexing are considered as one example of this technology. Coupling a closed loop resonator with a straight waveguide using evanescent coupling leads to a filter behaviour of the new structure. Careful choice of coupling coefficients between the rings and the buses are of great importance in deciding the shape of the filter response. An analysis of different structures of multi-ring coupled resonators are presented in this paper. A comparison of filter responses and the effect of different parameters on the resonant frequency are shown. Analysus was carried using space coupled mode theory and signal flow method to analyse optical multi-paths ring resonators, the results have been validated using CST showing good agreement between the analytical and simulation based results.
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