The essential elements found in most types of connectors:

  • A ferrule, which is used to align the core inside the connector.
  • An anti-rotation device, to prevent rotation of the ferrules, and thus end face damage. Also for alignment of the APC connectors.
  • An end-pressure control device (spring) to control the end pressure on the ferrules.
  • A strain-relief system to transfer tension from the connector to the strength member, and prevent loss of light due to sharp bending of the connected fiber.

Optical Fibre Connector Grade:

‘Grade C’:

  • Attenuation: 0.25dB mean, ≤0.50dB max, for >97% of samples
  • Return Loss: ≥35dB

‘Grade B’:

  • 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):

  • 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.

Colour Coding

The connector and / or strain relief sleeve or boot is usually colour coded to provide indication of the end face type and or the fiber type There are additional typical colours often used to identify particular patch lead types . For example:

  • SMF APC : Green connector, Patch leads are usually yellow
  • SMF PC: Blue connector, Patch leads are usually yellow
  • MMF: Beige connector. OM3 / OM4 patch leads are usually mid-blue.

Colour Coding of Fibre Optic Patch Cable

At 650nm, the attenuation is about 7dB/km for single mode fibre.

Human eyes could spot the red 650nm light in the field at power level around -45dBm, and in the dark environment, the visibility is at power level of -50dBm.

For a 10mW 650nm Visual Fault Locator (VFL), which is +10dBm, the travel distance in the field, may be reach up to 8km, and in a dark environment, it may reach 9km.


Singlemode Fibre OS1 vs 0S2

G.657A (for Access networks)

  • A1 fibre, 10 mm bending radius
  • A2 fibre, 7.5 mm bending radius

Fully compliant with ITU-T G.652.D fibres.

G.657B (for short distances at the end of Access networks in bending-rich environments

e.g, buildings)

  • B1 fibre, 7.5 mm bending radius
  • B2 fibre, 5 mm bending radius

Cmpatible with ITU-T G.652.D fibres (only small differences in chromatic dispersion

and polarization mode dispersion (PMD)).

Fibre 12 colour