Installation Manual

For Technical Support: www.panduit.com/resources/install_maintain.asp

Page 3 of 12

BEST PRACTICES

FS061

Cracks

Cracks in the fiber are fractures of the material that may appear as lines on the surface. Unlike a

scratch, a crack can go deep into the fiber.

Cracks in the fiber can present the same types of problems as scratches, but cracks have the

potential to grow under load. Cracks near the edge of the fiber can lead to edge chips. Edge chips can

then become loose contamination and can affect the mating of the connector.

Fixed Contamination

Fixed contamination is material on the fiber end face surface that can be particularly stubborn to

remove or cannot be removed at all. This material can be present in the form of cured epoxy, stains,

or embedded particles.

This type of contamination can partially obscure light transmission and lead to higher than expected

insertion loss. In addition, such contamination can sometimes be reflective in nature resulting in a

low return loss.

The primary problem with fixed contamination present outside of the fiber core is that this material

may prevent or limit physical contact of the fiber end faces and cause both high insertion and low

return losses. Even if contamination of this type allows physical contact, separation of the end

faces may occur during expansion and contraction due to temperature fluctuations and this form of

contact may result in the damaging of the mated end face.

Loose Contamination

Loose contamination is debris on the surface of the connector that is not permanent and can be

removed with practices outlined in this document. Loose debris may include oil, grease, loose fibers,

or metallic particles.

This type of contamination can partially obscure light transmission and lead to higher than expected

insertion loss.

Pits

Pits in the connector endface are permanent features in the fiber or ceramic ferrule substrate that are

generally irregular shaped, where material has been removed due to polishing.

Pits can create the same problems as scratches. Significant pitting can increase insertion loss and

decrease return loss possibly preventing physical contact of the fiber cores when the connector is

mated.

Chips

Chips are areas were sizeable segments have broken out of the glass fiber (typically at boundary

areas such as the clad edge). These flaws occur most during the polishing and cleaving processes

and can negatively impact the optical characteristics of the connector by acting as a “dirt-trap” for

contaminations.

Chips within the core region can result in high insertion loss due to local refractive change and impair

return loss due to chips being undercut with respect to the physical contact area creating areas of

high Fresnel loss. Fresnel loss is the loss that takes place at any discontinuity of refractive index,

especially at an air-glass interface such as a fiber end face, at which a fraction of the optical signal is

reflected back toward the source.