Monday 8 August 2011

How is Infinera Different?


Carriers have told us that they want the benefits of digital networks for their optical layer. They want the service flexibility that comes from digital add/drop of any optical service at any network node. They want to simplify network engineering and operations through regular digital cleanup of analog optical impairments, digital grooming and multiplexing, and advanced digital coding. And they want these benefits in a network that costs less than the traditional "analog optical" alternative. In short, these carriers have created an alternative vision for the optical layer that we call the Digital Optical Network.
Digital Optical Networking is the antithesis of the way that most other optical networking vendors have chosen to evolve their network architectures. These vendors have chosen the "all-optical route" with all the drawbacks that this entails.
Infinera took a different approach. We began with the assumption that "digital is good". After all, the vast majority of data being carried over optical networks today is created in digital form. In addition, anything to do with administering or fault-finding the services that carry this data is also digital, and any attempts to mimic these OAM or performance management capabilities in the analog domain tend to be somewhat ineffective.
We decided we had to find a way to make "digital" work. To make it scale, and to make it economical to deploy and operate. The key was to allow economical Optical-Electrical-Optical (OEO) conversions.
OEO conversions are uneconomical in conventional networks because they involve a number of discrete optical components for each wavelength, multiplied by the number of wavelengths that DWDM allows us to transmit in a single fiber.
For example, to create a signal for an individual wavelength we typically need:
  • A source of light - such as a laser
  • A way to put a digital signal onto that light - known as a modulator
  • A means to ensure that the laser stays on the correct wavelength
  • Components that control the output power of the laser
A number of optical component companies have developed small scale PICs that combine a number of these components into the same chip package. Sometimes these PICs are built on the same semiconductor substrate, while sometimes they're simply combined together in the same package (see monolithic photonic integration vs co-packaging).
Infinera has pioneered the technique of large scale photonic integration. Our PICs integrate the components needed for ten different wavelengths onto a single chip. At the moment that means over fifty discrete optical components on a single transmit PIC, and we'll continue to drive integration of additional components and functions.

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