SBIR Phase I: Integrated Optical Monitor for Hybrid Opto-electronic Transmitter

This Small Business Innovation Research Phase I project describes a hybrid integrated circuit that consists of a vertical cavity surface emitting laser (VCSEL) fabricated on a III-V semiconductor wafer that is flip-chip bonded to a Silicon chip that contains a CMOS circuit used for driving the VCSEL and a Silicon detector that is used for monitoring the output power of the laser. Semiconductor lasers are typically supplied with discrete, external detectors that are used for power monitoring. We propose an integrated detector structure that would provide a simpler, more efficient, and cheaper solution. In this proposal, monitor detectors are designed into the Silicon CMOS laser driver circuits and are flip-chip bonded to the VCSELs creating a compact, three-dimensional circuit structure. This technology provides an optoelectronic-VLSI integrated circuit solution that can be accomplished in large arrays to achieve low cost. The result is wafer-level integration, packaging, and testing of photonic-on-VLSI leading to tremendous manufacturing efficiencies for transceiver modules. The commercial benefit of the proposed work is very straightforward. Monitoring functionality is critical for telecommunications and storage-area-network applications, but is currently not available with arrayed VCSEL transceivers that were originally produced for intra-system links for data-com applications. There is a strong market-pull for incorporating this functionality into parallel optical links. The invention would also enable more quantitative research into VCSEL degradation and lifetime measurements because of built-in real-time monitors on every VCSEL. Thus far this type of studies have relied on intermittent measurements on small sample populations. The invention would allow, for the first time, continuous, real-time reliability data to be gathered on VCSELs from deployed systems in the field.