ETRI tests DP-QPSK alternative for 100-Gbps metro networks

Korea’s Electronics and Telecommunications Research Institute (ETRI) says it has successfully trialed a 100-Gbps optical transceiver that uses an alternative to coherent-enabled dual-polarization quadrature phase-shift keying (DP-QPSK). The patent-pending modulation format, called dual-carrier differential quadrature phase-shift keying (DC-DQPSK) requires neither a DSP ASIC nor polarization tracking, ETRI asserts.

The trial took place over the National Information Society Agency’s (NIA’s) Korea Advanced Research Network (KOREN), a test bed network established for research, development, and international cooperation. NIA, KT, and Coweaver Co., Ltd. supported the field trial, which saw 100-Gbps transmission over a 510-km Daejeon-Seoul-Daejeon round-trip WDM link over a mix of standard singlemode fiber and NZ-DSF.

The test used a 100-Gigabit Ethernet CFP optical transceiver, an OTU4 framer, and a 100G OTN optical transceiver. This last module used the DC-DQPSK modulation format. The fact that the transceiver does not require polarization tracking or high-end DSP technology results in lower power consumption and lower cost than typical 100G coherent approaches, ETRI asserts.

“The hot spot of the 100G market will be in the range of 20 to 600 km,” says Dr. Kwangjoon Kim, director of ETRI’s optical transmission technology research team. “Our transceiver is compact and economically beneficial. Moreover, you can supply the 100G transceiver to any system vendor because it provides 168-pin electrical interface compliant with OIF MSA-100GLH.”

To complement the new modulation format, ETRI has developed IP cores for OTU4 framing, including OTL4.10 MLD interface, G.709 FEC, and CAUI interface, which are integrated in a single FPGA. ETRI also has developed a TO-can type 28G ROSA for its 100GbE CFP optical transceiver. The framer and CFP optical transceiver were also successfully tested in the field trial.

ETRI plans to display its new 100G technology during this year’s OFC/NFOEC event in Los Angeles at booth #930. The non-profit research organization says it is ready to transfer the 100G technology to any interested industrial manufacturer.

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