Due to their growing potential, Implantable Medical Devices (IMDs) are getting more complex and thus require more sophisticated wireless powering and communication systems. This paper introduces a new modulation technique based on pulse width modulation for data transmission across inductive links. The technique is called Quad-Level Carrier Width Modulation (QCWM). It allows high data-rate transmission and ultra low power consumption, while maintaining a simple implementation. A very simple fully integrated QCWM demodulator circuit is implemented using 130 nm IBM CMOS technology. Post-layout simulation results validate the feasibility of the proposed technique and show ultra-low power consumption of 35.5 μW drawn from a supply voltage of 1.2V when transmitting data at a rate of 10.85 Mbps.