ACADEMIA

This week at OFC/NFOEC 2012, silicon photonics developer Kotura plans to demonstrate its low-power 100-Gbps optical engine, which is designed to support the interconnect fabric for next-generation data centers and high performance computers (HPC).

Kotura's silicon photonics platform supports optical integrated products using WDM. As the only silicon photonics provider to offer WDM, Kotura says its optical engine provides distinct advantages, including reducing the cost of fiber and associated connectors within the interconnect fabric by a factor of four in 4x25-GHz approaches, with the potential to expand from four channels to 8, 16, or even 40 channels. Kotura's silicon photonics platform also supports parallel fiber channels.

"The optical engine provides our customers with an inexpensive, small form factor that reduces power consumption and provides a high level of integration," said Mehdi Asghari, CTO of Kotura. "Moreover, we are addressing the need for green solutions that will alleviate some of the strain associated with power hogs such as data centers and high performance computers."

Kotura has integrated multiple functions -- such as flip-chip attached lasers, high performance WDM de/multiplexers, fast low-power modulators, and high-speed detectors -- into a single pair of silicon chips, eliminating the need for hundreds of piece parts and dozens of assembly steps. Kotura says its optical engine is so small that a 100-Gbps transceiver will easily fit inside a QSFP package, the smallest 40G package on the market today, which will greatly increase the panel density of 100-Gbps transceivers.

The new chips are based on Kotura's micron-scale mass manufacturing platform, which is well established with parts deployed in live networks around the world since 2006, according to Kotura. With three of the five largest telecommunication OEMs using Kotura products in their 10, 40, and 100 Gbps network offerings, Kotura says it is approaching a million channels per year currently in production. As the optical engines can be produced in a high-yield manufacturing process, it is possible to achieve attractive price volume curves, the company says.

"We are in the early stages of a market with huge potential," said Brad Smith, senior vice president at Lightcounting, a market research analyst firm tracking high-speed interconnects. "100G in a QSFP package over a single strand of single-mode fiber is exactly what the HPC, traditional data center and switch/routing infrastructure is looking for to support next-generation systems and to gear up for the coming exaflood of data."

Finding fast enough interconnects has become the limiting factor for the entire industry. With 10-core microprocessors, four per server, virtualization, and 48-60 servers per rack, the aggregate bandwidth at the top-of-rack switch will hit 480-600G. This will require four to five 100G uplinks per rack and large data centers using 200-500 racks.

According to Smith, the advantages of silicon photonics are enormous, enabling optical WDM to move to the server and switch rack. Silicon photonics and WDM allow modulation speeds to increase to 40G/50G and more channels in the future without having to upgrade the entire fiber plant.