Fabrication of photonic devices needs nanometer‐scale precision for devices to be in the optimal point of operation. Achieving this precision typically requires complex and costly post‐fabrication processes or thermo‐optic tuning using resistive heaters. In this work, we demonstrate active trimming of ring resonators on a SiN platform using a cladding layer. A DC bias is applied in order to tune an optical modulator in the optimal point of operation while maintaining a constant high‐frequency response. This approach is promising for high‐speed applications where precise tuning is critical.