A Temperature Controller IC for Maximizing Si Micro-Ring Modulator Optical Modulation Amplitude

We present a custom-designed integrated circuit (IC) implemented in 0.25-μm BiCMOS technology that can automatically control the Si micro-ring modulator (MRM) temperature for optimal modulation characteristics. The IC monitors the optical modulation amplitude (OMA) of an Si MRM and provides the optimal heater setting for the maximum OMA. The IC consists of trans-impedance amplifier, power detector, track-and-hold circuit, comparator, digital-to-analog converter, and digital controller, all of which are integrated in a single chip. We demonstrate that, with this IC, an Si MRM can provide the maximum OMA for 25-Gb/s operation despite changes in temperature and input optical power.