Calculating Your Insertion Loss Budget

Calculating an Insertion Loss Link Loss budget isn’t a new topic. However, tolerances of Insertion Loss (IL) and Maximum Attenuation Allowance have become more important as the speed of data transmissions have grown throughout the years. All of these values are standards driven, available in ANSI/TIA-568-C.0 for performance and test requirements, and ANSI/TIA-568-C.3 for standards on fiber and connectors.

As an example, a 10G b/s fiber link in the data center over OM4 could easily reach 400m with a handful of mated pairs (defined as connector to patch panel, connector to cassette, or even splices with certain parameters for fiber type (ex, MMF) diameter (µm), wavelength (nm), maximum attenuation (dB/km), and modal bandwidth-length (MHz-km)).

With most data centers having 10 Gb/s uplinks in the rear view, and quickly surpassing 40 Gb/s, and now into 100 Gb/s and 400 Gb/s on the near horizon, there is less room for error for distance and performance as there was when data transmission speeds were ‘lower’. Also, as data centers are physically getting larger, leaf-spine networks are sprawling, and lossless transport is needed for storage services, link channel design is a necessity. With the service life of the average fiber cable plant at around 20 years, a small amount of additional IL/attenuation at 40 Gb/s will make a gigantic difference in fiber application reach when speeds are approaching 400 or 800 Gb/s and beyond.