Luxtera and Kotura have both demonstrated 100 Gbps QSFP optical modules based on silicon photonics technology.
The Luxtera QSFP is a four-channel integrated transceiver that uses a single laser and is tailored for 500m although Luxtera says it can achieve 2km. The Kotura QSFP, in contrast, uses two chips, has a reach of 2km and is a four-channel WDM design. Kotura also uses third-party electronics such as laser drivers and trans-impedance amplifiers (TIAs) whereas Luxtera develops and integrates its own.
Luxtera’s QSFP pluggable transceiver was shown at the recent OFC/NFOEC show as part of the Optical Internetworking Forum‘s (OIF) multi-vendor demonstration of its 4x25Gbps chip-to-module interface, known as the CEI-28G-VSR.
Chris Bergey, vice president of marketing at Luxtera, says the big Web 2.0 data centre operators like the reach and faceplate density offered by the 100Gbps QSFP as their data centres are physically large and use flatter, less tiered switch architectures.
The latest CFP2 module enables at least eight 100Gbps pluggable modules on a system’s front panel compared to four CFPs. But with the QSFP, up to 24 modules can be fitted while 48 are possible when mounted double-sided (belly-to-belly) across the panel.
Kotura is also targeting switch applications in the data centre with its device. The Kotura QSFP uses four 25Gbps wavelengths that operate around 1550nm.
“We picked 1550nm because that is where a lot of the WDM applications are,” said Arlon Martin, vice president of marketing at Kotura. “There are also some customers that want more than four channels.”
The Kotura design consumes 3.5W; Martin says 80 percent of the total power consumption is due to the electronics.
By Roy Rubenstein
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