Are all optic fibre patch cords created equal
Many people would answer yes to this question, as from first glance they all look physically similar. However, upon closer inspection and by measuring performance, it is quite obvious that the quality can vary greatly.
For many people in the IT and telecoms industry, a fibre optic patch lead (also known as an optic fibre patch cord) is now considered a commodity item.
However, when choosing to buy the best quality singlemode fibre optic patch leads, the following should be considered:
What is Fibre Optic Patch Lead Connector Grade (Performance)?
IEC standards dictate the connector performance requirement for each grade of fibre optic patch lead connector. These standards guide end users and manufacturers in ensuring compliance with best practices in optical fibre technology.
Generally, Grade A, B or C options are available, with Grade A providing the best performance.
According to IEC 61753 and IEC 61300-3-34 Attenuation Random Testing Method, ‘Grade C’ connectors have the following performance characteristics: Attenuation: 0.25dB mean, >0.50dB max, for >97% of samples. Return Loss: >35dB.
‘Grade B’ connectors have the following performance characteristics: Attenuation: 0.12dB mean, >0.25dB max, for >97% of samples. Return Loss: >45dB.
‘Grade A’ connector performance (which is still yet to be officially ratified by IEC) has the following performance characteristics: Attenuation: 0.07dB mean, >0.15dB max, for >97% of samples. While the Return Loss using IEC 61300-3-6 Random Mated Method is >55dB (unmated – only angled connectors) and >60dB (mated), this performance level is generally available for LC, A/SC, SC and E2000 interfaces.
What Singlemode Optic Fibre Types are available?
For singlemode fibre optic patch leads, two fibre types are generally available, G652D or G657A2.
G652D and G657A2 specifications refer to the glass and cable construction of optical fibre and are generally the fibres of choice in optical fibre patch leads for singlemode systems.
657A2 optical fibre in patch leads, provide an improved bend radius and flexibility, which may allow for better cable management and routing in congested areas. The improved bend radius may also allow for increased density in high-density patching fields. G657A2 optical fibre is becoming very popular in Data Centre and Enterprise network deployments.
What are Optical Fibre Connector types?
For singlemode optical fibre patch leads, the following connector types are available, LC, SC, SC/A, ST, FC, E2000.
The most common types of connectors used in modern transmission systems are SC, SC/A and LC (either simplex or duplex connectors).
Selecting the correct patch lead connector type is usually dictated by the transmission equipment or patch panel that the patch lead needs to connect with.
Why the Optical Fibre Cable Diameter is important
In high-density patching areas, the selected patch lead cable diameter can either increase or decrease congestion. It is generally recommended that simplex fibre optic patch leads have a diameter of approximately 2mm.
When selecting duplex singlemode fibre optic patch leads, there are a couple of options. Firstly, a figure 8 (2 x 2mm cords) patch cord is available, with each connector being physically separated (simplex connector). Secondly, the more common option for duplex fibre patch leads is a round 3mm duplex cable. This option requires the use of a uniboot duplex fibre optic connector, however, the smaller cable diameter helps reduce congestion in patching fields.