Reconfigurable and non-blocking photonic switches are essential building blocks for next-generation broadband optical interconnects and integrated optical networks. We present the design, fabrication, and experimental demonstration of a compact 3×3 thermo-optic silicon photonic switch implemented by cascading 2×2 restricted-interference MMI units in an MZI–MMI configuration to ensure high stability, fabrication tolerance, and broadband operation. Fabricated on a CMOS-compatible SOI platform using 193-nm DUV lithography and integrated with optimized Ti/W heaters for low-voltage control, the device exhibits robust broadband operation around the C-band. At the central operating wavelength of 1549.5 nm, nine measured switching states show power consumption in the range 19.95–56.65 mW. Overall performance metrics include insertion loss 1.5–6.2 dB, crosstalk ≤ −10 dB, extinction ratio up to 30 dB, and imbalance factor less than -12 dB across C-band. Furthermore, the proposed switch exhibits a fast-switching time of ~20 μs under 4–7 V actuation. The entire circuit occupies 0.75 mm × 1.5 mm. These results demonstrate the proposed 3×3 switch as a compact, broadband, and energy-efficient building block for OWXCs, ROADMs, large-scale PICs, and optical computing platforms.