Processing of high-speed data using optical signals is a promising approach for tackling the bandwidth and speed challenges of today's electronics. Realization of complex optical signal processing functionalities seems more possible than any time before, thanks to the recent achievements in silicon photonics towards large-scale photonic integration. In this Ph.D. work, a novel thermal reconfiguration technology is proposed and experimentally demonstrated for silicon photonics that is compact, low-loss, low-power, fast, with a large tuning-range. These properties are all required for large-scale optical signal processing and had not been simultaneously achieved in a single device technology prior to this work. This device technology is applied to a new class of resonator-based devices for reconfigurable nonlinear optical signal processing. For the first time, we have demonstrated the possibility of resonance wavelength tuning of individual resonances and their coupling coefficients. Using this new device concept, we have demonstrated tunable wavelength-conversion through four-wave mixing in a resonator-based silicon device for the first time.