An Optical Interconnect Transceiver at 1550 nm Using Low-Voltage Electroabsorption Modulators Directly Integrated to CMOS

A low-voltage, 90-nm CMOS optical interconnect transceiver operating at 1550-nm optical wavelength is presented. This is the first demonstration of a novel optoelectronic modulator architecture (the quasi-waveguide angled-facet electroabsorption modulator) in a system. It features a simple electronic packaging via flip-chip bonding to silicon. Devices have a broad optical bandwidth, are arrayed two dimensionally, and feature surface normal, spatially separated, and misalignment-tolerant optical ports. The modulators are driven with a novel pulsed-cascode driver capable of supplying an output-voltage swing of 2 V (twice the nominal 1-V CMOS supply) without overstressing thin-oxide core CMOS devices. At the receiver side, a sensitivity of -15.2 dBm is obtained with an integrating/double-sampling front end. The transceiver includes clock generation and recovery circuitry that enables a data serialization factor of five. At a maximum data rate of 1.8 Gb/s, the optical transmitter, receiver, and clocking circuitry consume 12.6, 4.5, and 6.5 mW, respectively, for a total link electrical power dissipation of 23.6 mW. To the best of our knowledge, this is the first demonstration of an interconnect transceiver operating at 1550 nm with a III-V output device directly integrated to the CMOS.