Patent ID: 8027591

Claim:
A drive circuit for a quantum well modulator, comprising: a bias voltage source coupled to the quantum well modulator and configured to supply a bias voltage to the quantum well modulator; a modulation voltage source configured to supply a modulating voltage to the quantum well modulator for changing an optical property thereof, a first switch coupled to the modulation voltage source and to the quantum well modulator, the first switch configured to deliver the modulating voltage to the quantum well modulator via a first conduction path according to a state of the first switch; a second switch coupled to the first switch and to the quantum well modulator, the second switch configured to return a current associated with the modulating voltage to the modulation voltage source via a second conduction path according to a state of the second switch; and a processor configured to vary the state of the first switch and the second switch such that the modulation voltage source alternately supplies the modulating voltage and returns the current to the modulation voltage source.