Composite optical phase controller for operatively coupled thermal-based and stress-based phase tuning of a surface waveguide

A method comprising:

• providing a first composite phase controller that includes:
• a first waveguide disposed on a substrate;
• a first stress-optic (SO) phase controller that is disposed on the first waveguide and configured to control a first stress in the first waveguide, wherein the first SO phase controller includes a first piezoelectric element disposed between a first pair of electrodes;
• and
• a first thermo-optic (TO) phase controller disposed on the first waveguide and configured to control a first temperature of the first waveguide, wherein the first TO phase controller includes a heater strip electrically connected between second pair of contacts;
• wherein the first composite phase controller is provided such that the first SO phase controller and first TO phase controller are operatively coupled and can collectively control a first propagation characteristic of a first light signal as it propagates through the first waveguide, and wherein the first propagation characteristic is selected from the group consisting of phase and speed of propagation
• optically coupling the first light signal into the first waveguide;
• and
• controlling at least one of the first SO phase controller and first TO phase controller to control the first propagation characteristic of the first light signal as it propagates through the first waveguide.