PDF of this tutorialAlthough the market for advanced dispersion compensation management solutions is nascent, many choices abound, and the number is growing quickly. To help ensure maximum return on investment in both the short- and long-term, companies contemplating the purchase of DCMs should consider the following “checklist” of attributes. The top three attributes include the following:
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One-stop shopping—The rapid emergence of high-speed networks gives equally rapid rise to not one, but three new technical challenges: chromatic, slope mismatch, and polarization mode dispersion. Most companies developing dispersion compensation solutions address only one of the three. The risk in this approach is that, once combined on a single network, DCMs from multiple vendors will not work together optimally. This creates the potential for purchasers to divert significant resources to tune the combined performance of the collection of DCMs, in order to assure peak performance.
Instead, choosing a single provider from which to procure a full suite of dispersion compensation solutions can dramatically mitigate integration and optimization risk and maximize network performance. A provider with a range of complementary dispersion compensation solutions—CD, slope mismatch, and PMD—can eliminate much potential delay and expense in ramping up high-performance networks to OC–192 speeds and beyond.
- Tunability—Again, the importance of tunable dispersion compensation solutions cannot be underestimated, particularly in solving chromatic dispersion in quickly growing OC–192 networks and the emerging area of polarization mode dispersion. Adaptive tunability is essential in allowing networks of the future to manage change as they adapt to variable path characteristics, environmental fluctuations, and configurations that are themselves in a constant state of change.
- Multichannel capability—Likewise, to realize the potential of OC–192 and OC–768 DWDM networks, DCM solutions featuring multichannel capability are an absolute must. Because OC–192 and OC–768 can have up to multiple dozens of channels, an ever-dwindling amount of space on telecommunications racks necessitates multichannel capability in dispersion compensation solutions.
Also highly important, any potential dispersion compensation solution should offer the following:
- High reliability—The highest-quality DCMs offer carrier-grade reliability, typically 99.999 percent uptime. As more and more components are introduced into a network, the number of potential points of failure rises directly. To proactively ensure as little network downtime as possible, DCMs must offer the highest levels of reliability.
- Fail-safe/one moving part—A key component of uptime is fail-safe design, with a minimum number of moving parts. Complex, sensitive optical networking devices with components such as thin films, isolators, and mirrors introduce a significant amount of operational risk into network operations.
- Ease of operation—Because they will be deployed at hundreds, or even thousands, of locations, the chosen DCMs must be easy to install and operate. Adaptive tunability—as opposed to manual tuning, which requires human intervention—plays a large role in streamlining ongoing operations and maintenance of DCMs.
- Compliance—“Future proofing” the network is a major concern of every carrier, in order to attain maximum ROI. Any dispersion compensation solution should ensure compatibility with the myriad components from disparate providers that compose networks both today and tomorrow.
- Low insertion loss—Because networks transmit at only nine dBm (decibels relative to milliwatt) of power, any device inserted into the network must have minimal loss. Some early-stage DCMs incur as much as eight dB of loss, which means that almost 85 percent of the light is lost; next-generation technology promises to deliver low insertion loss of only two to four dB.
