High-speed modulator driver circuit with enhanced drive capability

Abstract

Modulator driver for driving an electro-optical modulator in a high-speed optical communications system. In accordance with aspects of the present invention, a modulator driver is presented comprising an input differential limiting amplifier providing differential outputs coupled to a distributed enhanced drive output stage configuration, wherein said distributed enhanced drive output stage configuration comprises a plurality of inductively coupled enhanced drive differential amplifiers, each of said enhanced drive differential amplifiers comprising a plurality of transistors in a cascode configuration whereby the control electrode of the upper transistor in said cascode configuration is biased by a voltage having a modulation component derived from either an input signal to or output signal from said enhanced drive differential amplifier, for the purpose of providing an enhanced output voltage swing capability that exceeds the breakdown voltage of a single transistor. Other methods and apparatus are presented.

Dependencies are inferred from the claim text.