A device comprising: a light source configured to produce an optical signal; an optical waveguide configured to receive and convey the optical signal from the light source; an optical ring resonator coupled to the optical waveguide, the optical ring resonator configured to: receive the optical signal from the optical waveguide; and, at least one of modulate and filter the optical signal on the optical waveguide; a heater positioned to heat the optical ring resonator; a voltage control device positioned to change a voltage across the optical ring resonator; and, a controller in communication with the light source, the heater and the voltage control device, characterized in that the controller is configured to: control the light source to produce the optical signal at a power where self-heating shifts a resonance wavelength of the optical ring resonator by at least 10 picometers, the self-heating comprising absorption in the optical ring resonator of optical power from a received optical signal; and, prior to at least one of modulating and filtering the optical signal at the optical ring resonator, control the heater to an operating temperature at which the resonance wavelength of the optical ring resonator is greater than a respective wavelength of the optical signal, and; wherein at a given level of self-heating a peak in an extinction ratio of the optical ring resonator as a function of heater temperature is outside of a hysteresis region, and the controller is further configured to control the heater to the operating temperature from either a high-to-low temperature adjustment direction or a low-to-high temperature adjustment direction. a light source configured to produce an optical signal; an optical waveguide configured to receive and convey the optical signal from the light source; an optical ring resonator coupled to the optical waveguide, the optical ring resonator configured to: receive the optical signal from the optical waveguide; and, at least one of modulate and filter the optical signal on the optical waveguide; a heater positioned to heat the optical ring resonator; a voltage control device positioned to change a voltage across the optical ring resonator; and, a controller in communication with the light source, the heater and the voltage control device, characterized in that the controller is configured to: control the light source to produce the optical signal at a power where self-heating shifts a resonance wavelength of the optical ring resonator by at least 10 picometers, the self-heating comprising absorption in the optical ring resonator of optical power from a received optical signal; and, prior to at least one of modulating and filtering the optical signal at the optical ring resonator, control the heater to an operating temperature at which the resonance wavelength of the optical ring resonator is greater than a respective wavelength of the optical signal, and; wherein at a given level of self-heating a peak in an extinction ratio of the optical ring resonator as a function of heater temperature is outside of a hysteresis region, and the controller is further configured to control the heater to the operating temperature from either a high-to-low temperature adjustment direction or a low-to-high temperature adjustment direction. control the light source to produce the optical signal at a power where self-heating shifts a resonance wavelength of the optical ring resonator by at least 10 picometers, the self-heating comprising absorption in the optical ring resonator of optical power from a received optical signal; and, prior to at least one of modulating and filtering the optical signal at the optical ring resonator, control the heater to an operating temperature at which the resonance wavelength of the optical ring resonator is greater than a respective wavelength of the optical signal, and; wherein at a given level of self-heating a peak in an extinction ratio of the optical ring resonator as a function of heater temperature is outside of a hysteresis region, and the controller is further configured to control the heater to the operating temperature from either a high-to-low temperature adjustment direction or a low-to-high temperature adjustment direction.