On the road to OC-768 [optical carrier]

Optical fiber promises higher data rates, but first it must get around a few hurdles presented by physics. Optical networking's capacity is increasing in response to Web surfing, images attached to e-mail, and the development of remote-collaboration applications. All these applications consume significant amounts of bandwidth. Optical networking uses two basic methods to increase an optical fiber's transmission capacity. First, you can increase data transmission rates. Second, you can couple multiple wavelengths onto a single fiber. An obvious outgrowth of these two basic methods is to combine them by transmitting more quickly on individual wavelengths and packing more wavelengths onto a common optical fiber. In November 2000, Global Crossing teamed up with Lucent Technologies to upgrade a 70km fiber network in Belgium to a 40Gbps operating rate for an approximately one-week OC-768 field trial. Although the field trial produced promising results, an actual upgrade of the existing optical infrastructure might not occur for several years. This pessimism comes from several factors, most of which relate to physics The most significant problem arises from a simple fact of physics: As the data rate increases, pulses become narrower. Although the field trial indicated OC-768 can operate over modern optical fiber, the jury is still out on the effect of multiple wavelengths, each operating at 40 Gbps.