A high-speed, wide bandwidth data detection circuit includes a phase detection module, a data detection module, a loop filter, and a voltage controlled oscillator. The apparatus includes a load detector and a controller. a switched mode electronic transformer or electronic ballast having an input for receiving current at mains frequency and a means for stepping-up said mains frequency to a higher frequency e. The light-sensitive face of the monitor diode is optically coupled to a backside of the laser diode, on the other side from the light exit side of the resonator, the backside also emitting light. Wherein, when the first power voltage and the second power voltage are applied, the control circuit generates an isolation signal to disconnect the discharging path.