Opto-electronic modulator utilizing one or more heating elements
Described herein are methods, systems, and apparatuses to utilize an electro-optic modulator including one or more heating elements. The modulator can utilize one or more heating elements to control an absorption or phase shift of the modulated optical signal. At least the active region of the modulator and the one or more heating elements of the modulator are included in a thermal isolation region comprising a low thermal conductivity to thermally isolate the active region and the one or more heating elements from a substrate of the PIC.
1. A modulating system, comprising:
a substrate;
a waveguide supported by the substrate and configured to guide light;
an active region through which at least a portion of the waveguide extends;
a plurality of electrical contacts configured to produce an electric field in the active region, the electric field being dependent on a selectable voltage;
a heater positioned proximate the active region and configured to selectively heat the active region,
wherein operatively the electric field and heater vary at least one of:
a refractive index in the active region, so that variations in the refractive index modulate a phase of the light in the waveguide, and
an absorption in the active region, so that variations in the absorption modulate an intensity of the light in the waveguide;
a heat sink supported by the substrate; and
a thermal isolation region formed from a material having a lower thermal conductivity than the substrate, the thermal isolation region configured to thermally isolate the active region and the heater from the substrate and from the heat sink.
2. The modulating system of claim 1 , wherein the heater is an electrically resistive heater.
3. The modulating system of claim 2 wherein the electrically resistive heater comprises a termination resistor connected between two of the plurality of electrical contacts.
4. The modulating system of claim 2 , further comprising circuitry configured to provide the selectable voltage to the plurality of electrical contacts, and provide a selectable current to the heater.
5. The modulating system of claim 4 , wherein the circuitry is configured to provide the selectable voltage to the plurality of electrical contacts in response to a detected wavelength change in the light directed through the active region, the selectable voltage being selected to stabilize a phase or an intensity of the light directed through the active region.
6. The modulating system of claim 5 , wherein the circuitry is configured to provide the selectable current to set a temperature at the active region to a specified value.
7. The modulating system of claim 1 , wherein:
operatively, the electric field and heater vary the refractive index in the active region, so that variations in the refractive index modulate a phase of the light in the waveguide; and
the modulating system functions as an electro-absorption modulator.
8. The modulating system of claim 1 , wherein:
operatively, the electric field and heater vary the absorption in the active region, so that variations in the absorption modulate an intensity of the light in the waveguide;
wherein the modulating system functions as an electro-optic modulator; and
further comprising a second electro-optical modulator arranged in a push-pull configuration with the electro-optic modulator to form a Mach-Zehnder modulator.
9. The modulating system of claim 1 , further comprising a plurality of independently-controlled heaters positioned proximate the active region and configured to selectively heat respective portions of the active region.