Why low attenuation interconnects in data centres?

Data centres are growing. Yet they must remain flexible, or there remains the real danger that the data signal drops below a critical level. Thankfully, there is an answer: low attenuation optical interconnects.

Modern, larger data centres require structured cabling to deliver an agile infrastructure. However, this is a setup which uses more than one patch cord and multiple connections in combination with a single trunk cable. When building or remodeling a data centre, more patch cords, cassettes and trunks in one link also provide increased flexibility in configuration. However, for this to work – and to mitigate the dangers of excessive data signal loss – low attenuation optical interconnects are required. In order to achieve this low loss, there are a number of considerations.

The optical power a laser can generate in a transceiver is, naturally, limited. Equally, so is the sensitivity of the detector in the transceiver. Framed by these limitations only the smallest amount of light is required, or desirable, to generate a clear signal. As the volume of interconnects between two transceivers increases, the connector’s attenuation decreases. When executed properly, this strictly limits loss of light (total optical attenuation).

By not fully absorbing the optical power capacity of a link within the fibre and / or interconnects, it becomes possible to significantly reduce signal loss, as a result of lowering the laser drive within the transceiver. This saves you money, energy and – best of all – keeps the temperature low.

Yet, this level of performance from connectors and cabling is more easily said than done. I often use the example of a garden hose. You have to align two hoses correctly, otherwise you lose water. The same principle applies to fibre optics, except in this scenario it is light we are losing; and the cost of achieving this alignment is much higher. Given an optical fibre has a diameter of 125 micro metres (or slightly less than a human hair) this naturally demands perfection.

As such, the optical attenuation of an interconnect is all about ensuring the correct alignment between the connecting fibres as well as making sure the fibres are “touching” each other without an air gap. The result if this done well? A more efficient, cost effective and flexible data centre.