To be passive is not necessarily to be ineffective. Consider the historical value of passive resistance in the struggle for political freedom, and the safety value of passive restraint systems. Passive optical components have been critical elements in fiberoptic system design from the outset. One could argue that optical fiber itself is one long, thin passive component, although we tend instead to talk about passive components as being circulators, micro-optics, thin-film filters, gratings, and the like.
In fact, it's becoming more difficult to separate passive components and their "apparent" opposites, active components. As more and more formerly separate components become integrated—whether on a substrate or within a module—the boundaries become blurred. For example, is a variable optical attenuator (VOA) passive or active? Some sort of force is applied to it to change its properties and effect on light, which would argue for the "active" designation. Yet it's usually classified as passive. And forget that argument—what about the case in which VOAs are added to an arrayed waveguide? Surely the integrated package could be termed active?
In this issue we stick to the classic type of passive component, but I think the subject matter shows that they too have an "impact." Guy Sauvé from ITF Optical argues that designers cannot just assume that passive components that perform well at 2.5 and 10 Gbit/s will do so at 40 Gbit/s; new thinking is needed. The components he describes are also the subjects of articles by Wallace Latimer at Edmund Scientific and Ivan Maksymyk at StockerYale, who write on the production of coatings and fiber Bragg gratings, respectively. Consultant Joe Shiefman adds another twist when he describes the tolerance challenges inherent in optical manufacturing and how software can help determine proper alignment and performance. All of these articles reflect the dynamic happenings under way in the passive-component world.
MORE OF THE SAME
There is much more in this issue than passive components. For example, Eric Chen and Donald Lu at J. P. Morgan Securities present Part 1 of their conclusions about the state of the component manufacturing industry, and its sustainability. And Rajive Dhar and Mark Lowry at Atoga Systems show how metro networks can make use of tunable lasers.
My point is that, in this our first independent issue, we remain committed to providing a variety of sophisticated and technically useful articles that will help you meet the challenges of engineering the optical network. This last phrase, conveniently, is our cover tag line accompanying the new, more readable page layout inside. With 35,000 readers, we have a lot of challenges to meet—which appeals to my passive-aggressive nature.
W. Conard Holton
Associate Publisher/Editor in Chief