A compact directional coupler fabricated on a silicon photonic platform is presented, with a power-splitting ratio that can be tuned through a transverse temperature gradient induced by a laterally shifted integrated heater. The tuning mechanism exploits the thermally induced phase velocity mismatch between the coupled modes of the silicon waveguides. The positions of the integrated heater and the waveguide design are optimized to maximize the tuning range and to reduce electric power consumption. Asynchronous devices with an intrinsic phase mismatch are demonstrated to be more efficient, providing a tunable coupled power from 0.7 to 0.01 with 36 mW maximum power dissipation.
© 2013 Optical Society of America
Original Manuscript: December 26, 2012
Revised Manuscript: February 6, 2013
Manuscript Accepted: February 6, 2013
Published: March 11, 2013
Piero Orlandi, Francesco Morichetti, Michael John Strain, Marc Sorel, Andrea Melloni, and Paolo Bassi, "Tunable silicon photonics directional coupler driven by a transverse temperature gradient," Opt. Lett. 38, 863-865 (2013)