On-chip reconfigurable mode converter based on cross-connected subwavelength Y-junctions
Longhui Lu, Deming Liu, Max Yan, Minming Zhang
Abstract
A novel power-efficient reconfigurable mode converter is proposed and experimentally demonstrated based on cross-connected symmetric Y-junctions assisted by thermo-optic phase shifters on a silicon-on-insulator platform. Instead of using conventional Y-junctions, subwavelength symmetric Y-junctions are utilized to enhance the mode splitting ability. The reconfigurable functionality can be realized by controlling the induced phase differences. Benefited from the cross-connected scheme, the number of heating electrodes can be effectively reduced, while the performance of the device is maintained. With only one-step etching, our fabricated device shows the average insertion losses and cross talks are less than 2.45 and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mo form="prefix">−</mml:mo> <mml:mn>16.6</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>dB</mml:mi> </mml:mrow> </mml:math> , respectively, measured with conversions between two arbitrary compositions of the first four TE modes over an observable 60 nm bandwidth. The converter is switchable and CMOS-compatible, and could be extended for more modes; hence, it can be potentially deployed for advanced and flexible mode multiplexing optical networks-on-chip.