Last week I wrote about the Photonics Summit and hands-on training hosted by Cadence Design, PhoeniX Software and Lumerical Solutions and in that article I mentioned that Ted Letavic of Global Foundries laid out a powerful argument for why integrated photonics is a technology that is going main stream. This article dives into more details from Ted’s presentation. There are some basic misconceptions about photonics that need to be cleared up and Global Foundries did a good job of doing that in Ted’s presentation.
The first misconception is that integrated photonics will be a small niche market. Ted did a nice job of pointing out that the major growth driver for photonics will be cloud-based computing. Up to 75% of enterprise IT deployments are now hybrid-Cloud based. Cloud deployments are driving most of the server, network and storage growth, and it’s that grow that will drive a 10X growth in data center traffic over the next five years. Mobile data is another contributing part of this growth and it alone is forecast to grow at an astounding 53% CAGR from ~6 exabytes (EB) in 2016 to over 30 EB in 2020. In conjunction with greater data volumes comes the need for greater data bandwidth and flexibility. Ted noted the two biggest drivers for increased bandwidth as being the new 5G standard for cellular networks and the dis-aggregation of the data centers with suppliers moving away from super centers to many smaller centers that are connected together with high band-width networks. Both of these drivers will require increased bandwidth density and speed and decreased latency. With this in mind, networking bandwidth is forecast to double every two years for the foreseeable future and integrated photonics will be the prevalent solution in all areas of networking for telecom (long and short haul), mobile networks and data centers. Transceivers alone for telecom and datacom are forecast to be a $3B market by 2020.
The second misconception is that integrated photonics is still in the labs and hasn’t made it to the production fabs. Global Foundries made it abundantly clear that they are ready to take production runs in as many as three different fabs (Fishkill 90nm/300mm, Burlington 90nm/200mm and Singapore 45nm/200-300mm). All of these fabs are able to run SiGe (silicon germanium) on SOI wafers and support PDKs with all of the necessary components for integrated photonic designs including vertical grating couplers, low loss edge couplers, dense high-contrast waveguides and passive components as well as high-speed active modular and photo detectors.
A third misconception about integrated photonics is that because photonic components are large in comparison to their transistor counterparts that 300mm lines would be overkill for such devices. As it turns out, signal loss is a key concern of large photonic circuits and many of the major sources of loss such as line-edge roughness in waveguides, alignment errors at junctions, and line-edge placement errors of resonant structures caused by poor critical dimension (CD) control, can be mitigated by 300mm tooling. Global Foundries showed results comparing their 200mm and 300mm tooling with the 300mm lines having a 3-5X reduction in CD and overlay errors, 2.5-3X reduction in line-edge roughness and a 4-5X reduction in CD and overlay errors in modulators giving them a substantial boost in their RF definition. This tooling combined with judicious optical proximity correction (another staple of 300mm processing) makes for a very low loss photonic platform.
A last misconception about integrated photonics is that monolithic solutions combining electronics and photonics are a long way off. Global Foundries has a solution now, says Letavic. Global Foundries’ offering boasts monolithic and hybrid process integration including high bandwidth RF and Analog for broadband systems and 5G synergy. To strengthen their offering, Letavic also pointed out that Global Foundries has a wealth of capabilities for handling advanced packaging (C4/Cu pillars, TSVs and MCMs) and test requirements and have included support for integrated photonics by adding lower-cost passive fiber alignment-and-attach technologies and surface grating couplers for inline on-wafer testing.
Letavic rounded out his presentation by outlining the fact that they have PDKs for their capabilities now that are compatible with the Cadence, PhoeniX, Lumerical EDPA (electronic-photonics design automation) flow covered by the rest of the photonic summit.
As I mentioned in my last article, this truly is a watershed event for photonics. The AIM Photonics effort in the U.S. needed a production fab into which designs could go from prototype to production and now they have not one, but three!