Analysis of inter-channel crosstalk in multi-mode parallel optical waveguide using Beam Propagation Method

We theoretically analyze the origin of inter-channel crosstalk in high-density multimode parallel optical waveguides for on-board interconnects using the Beam Propagation Method. In this paper, we demonstrate that inter-channel crosstalk due to mode coupling is very low in waveguides with GI-type circular cores because the propagation constants of the modes are discrete. Additionaly, it is also found that the waveguides with GI-type circular cores is sensitive to the optical confinment in the cladding: low power cladding modes largely decreases the mode conversion.