Networks - Connector Hygiene

Optical hygiene is a term used to describe the cleanliness of fibre end-faces in an optical network. Microscopic particles of dust, lint, or residue present on the core of a fibre can generate significant back reflections that can result in optical power degradation and instability in the source of the optical signal. The mating of dirty connectors can also embed particles into the glass surface of the fibre, creating scratches or pits that generate further losses. Regular application of inspection and cleaning protocols prevent and correct poor hygiene, and as a result, optimise network capacity and minimise network downtime.

Automated fibre scopes can inspect bulkhead and patch cord connectors, and grade them on a pass/fail basis.

Inspection

A fibre scope is used to check the condition of fibre connectors (patch cords or bulkheads) before mating with other fibres or network component to avoid damage to the fibre end-face.

The cross-section of a fibre end-face has three areas: the core, cladding, and ferrule. As the majority of light propagates through the core, particles that obstruct the core will have more impact than particles obstructing the cladding or ferrule.

The fibre end-face is always cleaned if a particle causes an inspection test to fail. It should then be re-inspected after cleaning.

Cleaning

Fibre cleaning is used to reduce contamination of the fibre end-face and provide a quality connection between fibre optic equipment. Typical cleaning techniques use lint-free and anti-static micro-fibre fabric to achieve this.

Typical contaminates range from 2 – 5 µm and include:

• Airbourne dust
• Residue
  • Skin oil
  • Distilled water
  • Salt water
  • Alcohol
• Hand lotion
• Graphite
• Clothing lint