Coupled optical waveguide resonators with heaters for thermo-optic control of wavelength and compound filter shape
An integrated optical device is disclosed comprising a substrate, optical waveguide, and compound optical resonator having a temperature sensor, at least two coupled optical resonators, and a heater localized to each optical resonator. An optical input signal is coupled to one of the resonators making up the compound resonator to form an optical output signal. The center wavelength and shape of the output signal is optimized with a feedback loop using the temperature sensor to control the power dissipated in at least one of the localized heaters. The power dissipated in the remaining resonator heaters is set according to a predetermined function having as an input variable the power dissipated in the resonant heater under control of the said feedback loop.
1. A method comprising the steps of:
providing a substrate;
forming a first and a second optical resonator on the substrate, the first optical resonator optically coupled to the second optical resonator;
forming first and second heaters on the substrate, the first heat being configured to adjust a temperature of the first resonator and the second heater being configured to adjust a temperature of the second resonator;
forming a temperature sensor on the substrate, the temperature sensor being configured to sense the temperature of the first resonator and the temperature of the second resonator;
actively controlling a power dissipated in the first heater to maintain an output of the temperature sensor at a value; and
adjusting the power dissipated in the second heater as a function of the power dissipated in the first heater.
2. The method of claim 1 , wherein the power dissipated in the second heater is a linear function of the power dissipated in the first heater.
3. The method of claim 1 , wherein the power dissipated in the second heater is a polynomial function of the power dissipated in the first heater.
4. The method of claim 1 , wherein the power dissipated in the second heater is a second order polynomial function of the power dissipated in the first heater.
5. The method of claim 1 , wherein power is supplied to the first and second heaters using pulse width modulation.
6. The method of claim 1 , wherein the second heater is one of a plurality of second heaters.
7. The method of claim 6 , wherein the first heater is one of a plurality of first heaters.