We experimentally demonstrate a silicon photonic modulator that can be loaded with a combination of lateral and interleaved p-n junctions to enhance its phase modulation. We use an asymmetric Bragg grating to introduce mode conversion in the active area, allowing the modulator to operate in reflection without introducing additional on-chip loss. With a compact footprint (phase shifter length of 290 μm), the modulator demonstrates a modulation speed up to 45 Gb/s with a bit error rate below the 7% forward-error-correction (FEC) threshold (up to 55 Gb/s with 20% FEC), and a low power consumption of 226 fJ/bit.