London Underground

We specialise in the termination of optical fibres, connectors and devices across diverse sectors, medical, aerospace, sensor, telecommunications, defence and more.

London Underground

Alker Fibre Optic specialises on mission-critical, high-risk industries that use fibre optics integrally within their equipment or assets.

Alker designs fibre optic solutions that help improve existing systems’ reliability and performance and extend the life of the overall products or services.

We are at the forefront of fibre optic repair, reverse engineering and lifetime support.

Fibre Optic Carriage and Link leads refurbishment is an example of these.

Brief: To repair broken legacy fibre optic connectors after carriages have been parted

What has been done:

  • Onsite assessment of internal and external fibre optics in each of the carriages;
  • Reverse engineered and manufactured all obsolescent fibre optic connector parts;
  • Designed all repair procedures to onsite regulations, including termination kit.

Over several months Alker has performed onsite visits to conduct emergency repairs of the fibre optic connectors within the train carriages. Alker has also refurbished the fibre optic link leads which connect two carriages. Requests for emergency repair were turned around the following morning denoting a level of service and response almost impossible to improve.  The fibre optics in the trains were inspected, and the condition of the fibre optics within the carriages and the link leads were found to have reached the end of their useful life.

Before and after pictures are examples of our work.


The end face of a fibre optic ferrule in service within one of the carriages.


The same ferrule after being refurbished by Alker.


5-way connector which the external link lead attaches to in order to connect the next carriage. 2 out of the 5 ferrules have been pulled completely out of the connector.


The same connector after being refurbished by Alker.

When the connectors body were disconnected, due to the extreme conditions, water corrosion and neglect they were subjected, the ferrules were pulled out.

The top ferrule is a new ferrule complete with spring, washer and a clamping nut. This is how the other two ferrules pictured below should look. The other two ferrules were in service; the middle one had the ferrule tip completely pulled out, and the spring is completely solid, the bottom one shows discolouration halfway up the ferrule. It was found jammed within the alignment sleeve, whereas it should be able to move freely up and down. The ferrules were reverse-engineered.

The damaged link leads have been refurbished by Alker off-site in our facility within a few days, halving the costs in this area and reducing delivery times from months.

The Benefits of the Fibre optic refurbishment:

  • Dramatic reduction of the need for new leads, saving both costs and delivery times.
  • Reduced stock, Alker could hold replacement refurbished leads in-house for next day delivery.
  • The near elimination of fibre optic loom replacement saving labour and cost of the loom.
  • Improved reliability for each carriage, and in turn, each complete train.
  • Increased transmission performance for each of the trains in service.
  • The Lifetime of the equipment will be extended as per the upgrade requirements

The fibre optic looms will on occasion have broken fibre tails within the loom. The contingency of 2 spare fibres within the system helps to extend the fibre optic loom’s working life as long as the remaining 3 fibre links are subjected to the refurbishment as well.

This further reduces the need for expensive replacements and lengthy delays installing a new fibre optic loom.

Case Studies

Inspection & Cleaning

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Bifurcated/Trifurcated

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London Underground

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Imperial College London

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Fred Olsen Renewables

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We look forward to hearing from you with our next challenge

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