Inphi® Corp., a leader in analog performance and signal integrity, announced the successful interoperability demonstration of its market leading 40G DQPSK modulator driver with Sierra Monolithics (SMI), a leader in 40 Gbps SerDes, multiplexer and clock multiplier unit (MUX/CMU). The result of this demonstration is the industry’s first reference design, which enables systems designers to develop next-generation 40G DQPSK optical communications systems rapidly.

“Inphi’s differential modulator driver fills the missing link in the 40G ecosystem,” said Jay Cormier, vice president of communications products and marketing at SMI. “Inphi’s 2514DZ works seamlessly with our MUX/CMU, the SMI4025. This demonstration paves the way for a rapid commercial development of 40G DQPSK systems.”

Loi Nguyen, Inphi vice president of PhyOptik business, stated, “During the interoperability demonstration, an excellent 40G DQPSK optical signal was obtained using the SMI4025 MUX/CMU, Inphi’s 2514DZ modulator driver, and a third party modulator. Together, these components are a key enabling solution to meet the high bandwidth requirements in the industry.”

DQPSK is an important modulation scheme for next-generation 40G optical transport systems. In 40G DQPSK transmission, two 20G NRZ electrical signals are optically modulated onto a single DQPSK optical bit stream at a rate of two bits per symbol. Thus, 40G DQPSK transmission occurs at one-half the symbol rates of a conventional NRZ modulation format, making it extremely resilient to impairments encountered in older fiber. System designers have demonstrated the effectiveness of 40G DQPSK systems for years, but until now, the components required to develop commercial systems have not been available.

Inphi, a market leader in 40G transimpedance amplifiers and a supplier of modulator drivers, announced the high performing differential modulator driver to the market, the 2514DZ, in January of this year. Already, this advanced solution is being used worldwide by more than 10 top tier OEMs and module vendors developing next-generation 40G and 100G optical communications solutions. Available for sampling immediately, Inphi’s 2514DZ modulator driver is expected to be available in production quantities in Q1 2009. Sierra Monolithics, a leader in both 40 Gbps and 100 Gbps SerDes, has a broad portfolio of products for both short-reach and long-reach applications that covers all the popular modulation formats used today. The 40G DQPSK SerDes chipset (SMI4025 & SMI4035) is available now, and is shipping in production quantities to the majority of OEMs using the 40G DQPSK modulation format.