Design of an EPIC
Electro-Photonic Integrated Circuits are designed in much the same manner as any integrated circuit, with a design environment that goes beyond the standard electrical components and offers seamlessly integrated optical libraries. Similar to how most existing foundries offer different variants of their design kits, as might be seen in analog and digital offerings of a particular node, an optical variant can be enabled in much the same way with few additional design rules necessary to aid in the design process. Consistent with the physical design, full electro-photonic schematic design and verification is possible, enabling anyone familiar with IC design to function as an efficient optical designer. An example of an EPIC design can be seen in Figure 2.
The benefits of electro-photonic design cannot be overstated because the integration of electronic and photonic components enables manners of design impossible to any other technology. Classical optical system design requires a discrete divide between optical and electrical components, which is unnecessary in EPICs. By using electro-photonic design, electrical interfaces to photonic elements can be distributed as needed throughout a system, reaping tremendous performance and functionality benefits over discrete optical systems. This benefit has already enabled dramatic power reductions in high speed optical modulators as well as new and unique optical monitoring functions to ensure interconnect security.
Electro-Photonics Integrated Circuits have already begun to see broad adoption in the data-communications market; however this initial foray represents just a small step into a much larger, long-term CMOS photonics market. While a scale of technology adoption similar to that of conventional semiconductor solutions is still years off, the ability of CMOS photonics to dramatically reduce the costs of optional systems is enabling it to make initial product penetrations, while rewriting the rules of transceiver markets long dominated by discrete optical solutions.
Leading the data-communications market are InfiniBand systems. Used in many of the world’s most advanced computers with quad data rate (QDR) systems, InfiniBand systems have successfully employed production grade CMOS photonics chips in high-performance data clusters already. This market is expected to grow and employ hundreds-of-thousands of CMOS photonics ICs per year. While InfiniBand is the leader in performance, larger datacom markets exist in the form of Ethernet and Fibre Channel interconnects. Both of these alternatives are expected to drive larger adoption of CMOS photonics for solutions at, or above, 10 Gbps. With the near-term adoption of 40G and 100G Ethernet solutions, 16G and 32G Fibre Channel, EDR InfiniBand, and other proprietary backplane solutions, the market for CMOS photonics ICs is expected to surpass 1 million units within the next 3 years.
While data-communications is a high growth market for CMOS photonics and vital to its adoption as the long term interconnect of choice, the real value
proposition for CMOS photonics is its ability to be integrated into any silicon IC. These applications could range from high performance computers that integrate the optical I/O directly into the CPU, obviating the need for a power hungry interconnect fabric (or several), to high speed consumer optics, enabling the growing demand for high bandwidth multimedia and advanced video interconnectivity. These steps will advance the market for CMOS photonics adoption, likely reaching the hundreds of millions of units and with growth limited only by the size of the semiconductor industry.