Opnext Inc. and Hitachi Ltd. announced the first wide-temperature range operation of 1310-nm 25 Gb/s EA-DFB (electro-absorption modulator with integrated distributed feedback) lasers for 100 Gigabit Ethernet 10-km, single-mode fiber (SMF) application at OFC/NFOEC 2008, held in February in San Diego.
"A study by the IEEE High-Speed Study Group showed that by the year 2010, the bandwidth required in core networking will be best satisfied by 100Gbit/s interfaces," Opnext said in a statement. "Furthermore, bandwidth needs are expected to double every 18 months, resulting in demand for multiport 100 Gb/s systems. In the IEEE 802.3ba taskforce, a 10-km SMF (single mode fiber) 100 Gigabit Ethernet specification is being discussed. For this application, 1310-nm four channels by 25 Gb/s wavelength division multiplexing transmission is the most attractive technology. One of the technology challenges is to achieve 1310-nm 25 Gb/s WDM optical devices. Course wavelength division multiplexing (CWDM) technology is expected to be the most cost-effective solution due to the wide wavelength pitch that enables 100 percent of wavelength yield and less strict or no temperature control."
Hitachi and Opnext said they have demonstrated EA-DFB lasers operating at 25 Gb/s with wavelengths of 1290-, 1310-, 1330- and 1350-nm. The 25 Gb/s operation was achieved using high-speed device technology, which has been already confirmed in 1550-nm 40 Gb/s EA-DFB lasers that are currently used commercially in 40 Gb/s transceivers. A wide temperature range operation from 0 ºC to 85 ºC was also reported. This was achieved using advanced aluminum-based material system in the EA modulator section, the companys said. The semiconductor material system has a temperature tolerant bandgap structure that decreases the temperature-dependent performance of the modulator.
"These EA-DFB lasers demonstrate the technical feasibility of the CWDM grid that achieves low-cost 100 G b/s optical transceiver modules with low power consumption and compact size, which is expected to accelerate the adoption of 100 Gb/s interfaces in the network," Opnext said.
Masahiko Aoki, a researcher at Hitachi's Central Research Laboratories, said, “The demonstrated 25 Gb/s 1310-nm CWDM EA-DFB lasers were achieved based on Hitachi’s advanced technology for uncooled and high-speed lasers which has already been demonstrated in previous work of uncooled 10 Gb/s and cooled 40 G bt/s EA-DFB lasers. We believe uncooled operation is the key to achieve small- and low-cost 100 Gigabit Ethernet transceivers for LAN applications.”
A post-deadline paper describing the results was presented at OFC/NFOEC 2008, held in February in San Diego.
For more information, visit: www.opnext.com