
We recently had the opportunity to sit down with Brad Smith, senior vice president at LightCounting, a research firm dedicated to the transceiver market. Brad oversees LightCounting’s transceiver-related semiconductor and optical markets coverage, so he has a unique view on active optical cables (AOCs). He was gracious enough to answer our questions and share his perspective with us. Part 1 of our conversation is below for your reading pleasure.
At the same time, we’re also pleased to announce the debut of the Five Minutes With… format, a recurring feature on Lightspeed, where we’ll speak with industry experts, who will provide their insights and opinions on a particular topic. We look forward to bringing you more of these in the coming months and welcome your feedback. Let us know what you think in the comments below.
Five Minutes with Brad Smith of LightCounting
Lightspeed (LS): When was the first time you remember hearing the term ‘active optical cable’?
Brad Smith (BS): In a 2007 Lightwave magazine article which showed a picture of Finisar’s Laserwire and its AOC connector-end. I thought it was an optical USB connector.
LS: In the early days, what was your market prognosis for active optical cables and, in hindsight, are you surprised about where the industry is now?
BS: IBM is the technical high ground for supercomputers and they said, (I’m paraphrasing here) “We are done with copper and going optical interconnects from now on.” Clearly AOCs are a great fit for Infiniband and HPCs. But the bigger market is in the corporate data center. With the exponential increase in data and traffic, coupled with the next AMD, Intel server upgrade, the data centers are clearly feeling pain and seeking faster interconnects beyond 1G. What is surprising is how difficult it has become to implement 10G in copper and the RJ-45 jack. The walk up from 10, 100, 1G was relatively non-eventful and the reach was always 50-100m. Implementing 10G in copper is turning out to be very hard and is still roughly two years away, whereas 10G, 40G and 120G AOC interconnects are available today and can alleviate a bunch of problems!
With AOCs, by simply closing off the optics to the end user, a huge number of limiting factors for optical interconnect adoption disappeared and innovation has popped with a large drop in cost. This reduced cost coupled with the large number of interconnects typically required in a data center is enough to gain considerable attention by purchasers in many applications. LightCounting is forecasting that the AOC concept will spread outside Infiniband to Ethernet, Fiber Channel, SAS and other areas that need 10Gbps and reach beyond 5m.
LS: What do you believe are the key advantages of AOCs?
BS: In my view, the main advantages are:
• 10G Reach – As speed goes up, copper reach goes down. With AOCs, 1cm or 100m makes no difference! 10G is available now with AOCs and data center managers don’t have to wait 2 years for 10GBase-T solutions. Data center architects want to put the systems where they want and not be limited by interconnect reach issues.
• Aggregate data rate – 10,40, 120, 150Gs – With a single 12x AOC, systems architects can have a short reach 100G channel today and they don’t have to wait for the single-fiber, 100G IEEE standards to sort things out. Also, a system designer can implement 1Tb over 100m+ with just 7-8 12-channel AOCs (12x10G, 12×12.5G). A few years ago, 1Tb was the rate the industry used to describe the aggregate data traffic between countries! Finisar’s 12×12.5G AOCs puts 150 1G links into the diameter of one Cat-5e cable.
• Low Power consumption – Data centers consume so much power that collectively it is being measured as a percentage of a nation’s electricity consumption figures! Large datacenters can consume $1-2M/month in electricity to power and cool the electronics. Today, it is becoming a major limitation both technically and financially. A single 10GBase-T copper interconnect today consumes ~10-15W per line card end and promises 6-8W with new chips in a few years. Finisar and a few other vendors’ 12x10G AOC consumes 1-3W/end and that is for twelve 10G channels, not just one!
• Other considerations – Size and weight of the cable, simplicity of design (compared to 10GBase-T chip complexity) and the price convergence with copper. When one examines the total cost of ownership (TCO) including power, maintenance and related issues, AOCs clearly make a lot of sense. At the TCO level, AOCs are on par, if not better than copper interconnects.
Stay tuned to Lightspeed for Part II of our conversation with Brad coming soon.