Techno-Economic Comparison of Silicon Photonics and Multimode VCSELs

Recent technical and commercial milestones in Silicon Photonics technology including its introduction into commercial foundries, and successful integration of most optical components, as well as the choice of single mode fiber in some mega data centers have prompted the speculation that Si photonics is the new low cost solution for optical interconnects and that it may replace multi-mode vertical cavity surface emitting lasers (MM VCSEL). We show that the dominant technology has to offer the lowest cost for the single channel transceiver application, which represents 90% of the data center market and which historically dominates sales. We show that Si photonics is currently significantly more expensive than MM VCSEL for single channel, but that it can make a successful entry into the four channel single mode market with significant growth, capturing 20% of the data center market. We discuss the challenges with Si/InP integration; i.e., hybrid lasers for breaking the cost barrier and to enter the market. We show that both MM VCSEL and Si photonics technologies can operate at 50 Gb/s. We discuss the transmission reach limitations of Si photonics and MM VCSEL and show an example of reach extension for 100 Gb/s using MM VCSEL to 300 m of MM fiber. In addition we show that MM VCSEL has fundamentally lower power consumption than Si photonics and is a good candidate for super-computing applications.