17 September 2002 -- At last week's ECOC 2002 event in Copenhagen, Denmark, linear optical amplifiers (LOA) developer Genoa Corp demonstrated the world's first 160km, 4-channel link without regeneration, for coarse wavelength division multiplexing (CWDM) applications using AllWave fibre from OFS and CWDM components from Finisar. Sweden's Transmode Systems also demonstrated its amplified CWDM system in Genoa's booth.
"By using Genoa's LOA and our AllWave zero-water-peak fibre, the reach of CWDM systems nearly doubles," claims Santanu Das, OFS' director metro optical system engineering.
CWDM, targeted at the metro, access and storage area network (SAN) markets, transmits a modest number of channels in the 1460-1620nm band with coarse 20nm spacing. The relaxed tolerances permit use of equipment that costs as little as 30% of that required for long-haul DWDM links, says Genoa.
But no optical amplifier, particularly the erbium doped fiber amplifier (EDFA), has until now had the necessary bandwidth to accommodate more than one or two CWDM channels at once. Genoa says that its LOA, claimed to be the world's first chip-based multi-channel optical amplifier, has a gain of greater than 10dB between 1500 and 1610nm, sufficient for four CWDM channels. By contrast, erbium-based amplifiers can only operate in the C band (1530-1562nm) and L band (1570-1610nm), covering one or two channels at a time.
"People tend to think optical amplifiers are interchangeable - you can substitute one for the other," added Gerlas van den Hoven, vice president of product management for Genoa. "But here that is not the case."
Gartner Dataquest has forecast the metro access market for 2005 to reach USD4.5bn. According to some estimates, as much as 20-30% of that may be expended on CWDM technology alone, particularly with the recent passage of the ITU's CWDM specification.