Fujitsu Pushes PON Splits

The Fujitsu Laboratories arm of Fujitsu Ltd. (Tokyo: 6702; London: FUJ; OTC: FJTSY) says it has developed an amplifier array that could increase the number of homes or businesses a Passive Optical Network (PON) serves.

The technology was presented at ECOC last month and was announced in press-release form Thursday.

Fujitsu's scheme uses Semiconductor Optical Amplifiers (SOAs) to boost upstream traffic. Four of these sit in the PON remote node, each one serving 32 incoming lines. That gives the remote node a split ratio of 1:128 as opposed to the more normal 1:32.

The key is that the SOAs activate only when an upstream burst of traffic arrives. That limits the noise the amplifiers add to the line -- noise being a big problem in normal SOA deployments, according to Fujitsu. The company also says it's got a way to fabricate the four amplifiers in one module, which could help save space in the remote node.



Why this matters
The number of potential PON endpoints is increasing, not only because of broadband buildouts but because PONs are being considered for new roles such as mobile backhaul and data-center interconnections. Fujitsu further argues that cloud computing will cause more stuff to get attached to the network in general, which would imply that more PON endpoints could emerge wherever PONs are being built.

One way to scale PONs accordingly would be to increase the split ratio. A 1:128 ratio has been discussed for some time; Fujitsu's proposal just sounds like it could make that concept a little more practical.

For more
Some recent tidbits about the progress of fiber access:

— Craig Matsumoto, West Coast Editor, Light Reading