Low-Crosstalk in Silicon-On-Insulator Waveguide Crossings With Optimized-Angle

Low crosstalk losses in silicon-on-insulator waveguides are demonstrated by choosing the optimum crossing angle. It is obtained that by using the crossing angles of 60deg or 120deg instead of the conventional 90deg crossing angle crosstalk losses are improved by more than 10 dB without degrading transmission losses. Experimental results show a very good agreement with three-dimensional finite-difference time-domain simulation results. The proposed crossing structure has a high compactness, a broad bandwidth with almost flat transmission losses and constant crosstalk losses, and is robust against fabrication inaccuracies.