The Study Of Elliptic Optical Filter Based On Microring Resonators

Optical filters based on the coupled micro-ring resonator (CMR) are important devices in the field of integrated optics. The paper select six order elliptic filter with two-dimensional topology as the research object, and obtain a new topology structure. Compared with the classical folding structure, the new topology has the advantages of less negative coupling coefficient. And then the paper study the method to realize negative coupling coefficient in the new topology.This paper establishes a theoretical model of a weakly coupled general topological condition for two-dimensional elliptic micro-ring filter from the angle of energy coupling. Then this paper chooses six order filter as the research object, through many set rotation center and angle of rotation transform, repeatedly, to specific elements of the coupling matrix of the zero one by one, get new coupling matrix. This transformation results compared with the classical folding matrix, eigenvalues and eigenvectors corresponding to different invariant, topological structure, and the coupling coefficients for a number of negative elements are reduced from two to one, thereby reducing the difficulty of realization of filter.How to realize the negative coupling coefficient has been the difficulty in the design of micro-ring filter. On this basis, this paper further puts forward the guide wavelength of the structure can be offset by1/8, depending on the phase difference between the accumulation of ring to realize negative coupling coefficient, and the use of field coupling theory made a theoretical derivation of the method.Finally, according to the design method and step are given in the paper, the specific design of the pass-band ripple is less than0.05dB, examples of stop-band rejection level40dB oval micro-ring filter. Experiments prove that the new topology of folding topology with the classic with transfer function the same, while the negative coefficient less make it more superiority.