Tunable broadband mode power dividers based on a wavelength-insensitive coupler using the thermo-optic effect for flexible modal power adjustment in a mode-division multiplexing network

Abstract

We demonstrate tunable broadband two-mode power dividers based on a wavelength-insensitive coupler for a mode-division multiplexing system. Ultra-small T E 0 − T E 1 and T E 0 − T E 2 mode dividers based on Si-wire waveguides are designed based on the coupled-mode theory. Tunability is achieved by using the thermo-optic effect. In both dividers, arbitrary branching ratios can be realized over a wide wavelength range. We experimentally demonstrated for the first time, to the best of our knowledge, a tunable T E 0 − T E 1 mode divider based on Si-wire waveguides. From the experimental results, an arbitrary branching ratio can be achieved by adjusting the injection current to a TiN heater placed on top of one of the delay lines.