A*Star, Fujikura demo 60G silicon photonics modulator

In collaboration with Fujikura Ltd., researchers from Singapore’s A*STAR Institute of Microelectronics (IME) have pioneered what they claim is the world’s first 40- to 60-Gbps silicon-based optical modulators that support advanced multi-level modulation formats for high-speed long-haul data transmission. The development represents a major advance towards low cost, ultra-high bandwidth, and small footprint optical communications technology on silicon platforms, the companies claim.

The adoption of multilevel modulations, in a simple quadrature phase-shift keying (QPSK) and differential-QPSK (DQPSK) format, significantly increases the information capacity and thus total data communication throughput for a given optical channel.

Comprising a set of silicon phase-shifters that are integrated in a nested Mach-Zehnder configuration, the modulator has demonstrated speeds of more than 40 Gbps for DQPSK and more than 60 Gbps for QPSK respectively. For instance, for a channel grid spacing of 50 GHz, 40G DQPSK results in a spectral efficiency that is 2X greater than the conventional on/off keying (OOK) format at 20 Gbps. Compared to conventional lithium niobate modulators, the new modulator is much smaller in footprint and is significantly cheaper to fabricate as it is CMOS-compatible, according to A*STAR.

A*STAR and Fujikura have been working together since 2006 to develop optical telecommunications component technologies. In the last two years, this joint effort has resulted in the release of an evaluation 10-Gbps silicon modulator that the parties assert features excellent performance for mass production (see “IME, Fujikura partner for optical modulators”). The partners say that the new modulator demonstrates that reaching ultra-high performance levels on silicon platform technology is now a reality and will drive ultra-high bandwidth optical communications.

“We are proud to have jointly achieved this breakthrough with Fujikura,” said Prof. Dim-Lee Kwong, executive director, IME. “This will fuel the design and development prospects of next-generation long-haul telecommunication systems as well as truly bring low-cost, high-performance optical communications to the masses.”

This achievement was reported at OFC/NEOEC 2013, held in Anaheim, CA.

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