Method And System For Electro-Absorption Modulator Drivers In CMOS

Abstract

Methods and systems for electro-absorption modulator drivers in CMOS may comprise an electro-absorption modulator optically coupled to a laser source and electrically coupled to a modulator driver circuit that is in a complementary metal oxide semiconductor (CMOS) chip. The electro-absorption modulator includes a summer for receiving a negative bias voltage and a programmable offset voltage, a voltage regulator for receiving the output of the summer and generating a negative DC voltage of lower magnitude than the negative bias voltage, level shifting circuitry for shifting a received data signal to a DC voltage level between the negative DC voltage from the voltage regulator and the negative bias voltage, and an electrical coupling structure for DC-coupling the level shifted data signal to the modulator. The bias voltage may be received from an off-chip low drop out (LDO) voltage regulator. The level shifting circuitry may include cascode CMOS transistors and a current mirror.

What is claimed is: 
     
         1 . A system, comprising:
 an electro-absorption modulator optically coupled to a laser source and electrically coupled to a modulator driver circuit, said modulator driver circuit being in a complementary metal oxide semiconductor (CMOS) chip and comprising:
 a summer for receiving a negative bias voltage and a fixed or programmable offset voltage; 
 a voltage regulator for receiving the output of the summer and generating a DC termination voltage of lower magnitude than said negative bias voltage; 
 level shifting circuitry for shifting a received data signal to a negative DC voltage level between said DC termination voltage from said voltage regulator and said negative bias voltage; and 
 an electrical coupling structure for DC-coupling said level shifted data signal to said modulator.