But now US components vendor JDSU has come up with a way to make EDFAs smaller, leaner and more manufacturable, which it unveiled at the European Conference on Optical Communications (ECOC) here in Brussels.
JDSU has replaced all the passive components inside the amplifier with a single planar lightwave circuit (PLC), and an isolator array mounted on the edge of the chip. To further save on space, it has combined the six photodetectors into an array, which is also mounted on the edge of the PLC chip.
In the first instance, JDSU has applied the PLC technology to its existing amplifier form factor to enhance manufacturability, improve yield, and increase performance.
All of these improvements arise because fibre couplings are eliminated. Every splice adds loss into the system, and creates a weak point from a reliability point of view. Some fibre couplings remain, in the gain flattening filter and the pump lasers, but overall the device is far more manufacturable, according to Sinclair Vass, director EMEA, for JDSU.
On top of that there's a cost saving that comes from reducing the number of components. Although the passives are relatively cheap components, there are lots of them.
"Integration has long been touted as a possible path to lower costs in optical communications, but most resulting products have fulfilled either technology or performance needs," says Daryl Inniss, VP and practice leader at market research firm Ovum. "The JDSU PIA [photonic integrated amplifier] platform appears to be based on applying integration to lower the cost of amplifiers, along with providing higher performance and flexibility. That is pretty powerful."
The PLC technology, combined with an upgraded printed circuit board design, will also enable JDSU to shrink the amplifier down to roughly two-thirds of its current size — meeting the requirements of systems vendors who want to save on board space.
The PLC chip takes advantage of the skills JDSU uses to build its reconfigurable-optical add-drop multiplexer (ROADM) devices, while the isolator array is the subject of a patent. These technology advances were revealed in a post-deadline paper presented at the Optical Fibre Communication (OFC) conference earlier this year, but now the technology has been commercialized.
The full-size EDFA using the PLC platform is currently beta sampling to customers, and will be generally available in the spring of 2009. It will be sold as an amplifier module, as well as an integrated function within JDSU's AON SuperBlade.
No doubt other amplifier vendors, who buy their passives from JDSU, will be hoping they can get their hands on the PLC technology too.
• For more details on the technology inside the module, see JDSU's press release here.