Leads to buy the best quality Singlemode Fiber Optic Patch cables?

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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.