Glowing fiber on road

Urban ICT Arena’s dark fiber network is owned by Stokab, which in turn is owned by the Stockholm City Council. Stokab is an independent provider of passive infrastructure consisting of optical fibers without active termination equipment, i.e. dark fiber. Since it was founded in 1994, Stokab’s goal has been to build competitively neutral infrastructure capable of meeting future communication needs, spurring economic activity, promoting diversity and freedom of choice, and minimizing disruptions to the city’s streets.

A fiber optic cable uses light pulses instead of electricity when it transfers information from one point to another. Fiber optics is by far the fastest technology for data transmission currently available and has virtually unlimited capacity.

An optical fiber connection is also reliable, insensitive to electronic interference and virtually impossible to intercept. It is the only viable option for companies with high security requirements for data communication.

The network is waiting for your participation

The fiber infrastructure consists of a network along a 2-kilometer-long stretch with 15 stations. Most of the stations are connected to lamp posts with access to electricity and the ability to charge any possible batteries. If the equipment is to be placed at a height of approximately 3 meters, maintenance can be done without a sky lift, but still be rather inaccessible to vandalism. Some has used equipment with an IP67 rating, which has been successful.

The light post at Jan Stenbecks torg (Station 6) is well equipped and has access to electricity around the clock. Urban ICT Arena will finance the installation of new equipment which has to be done by Stokabs contractors due to security reasons. Stokab is trying to coordinate the installation of equipment to take place a few times per year, in order to save costs.

If you are interested in taking part in this test bed, please contact . Please consider these questions:

  1. Which stations and locations are of interest?
  2. What will be the placement of the sensors? Up on the lamp posts or in the cabinet?
  3. What kind of infrastructure is required? A PoE Ethernet connection, or fiber, or some sort of wireless connection?
  4. How big are the sensors (and approx. weight)?
  5. When would you like to install them?


Current state of the stations

  • 1, 2 and 3 – Ready for usage.
  • 4 and 5 – Placed a bit too high according to the manufacturer.
  • 6 – Due to the design of the lamp post, installation can be a bit tricky. Has been vandalized.
  • 7 – Not currently in use.
  • 8 – In use and a good option.
  • 9 – The bus shelter. Can be used but requires some work. Users need to consider what kind of data collection is of interest and where the sensor is to be placed.
  • 10 – In use and a good option.
  • 11 – Can be used. Due to the placement on the bridge, users need to consider what kind of data collection is of interest.
  • 12 and 14 – Not yet in use.
  • 13 and 15 – Both are functional but due to the proximity of the stations, perhaps one would be enough.


What fiber is made of

An optical fiber cable consists of a pure silica core (SiO2) and a cladding used to reflect light pulses. The number of fibers in a cable can vary. Stokab’s cable dimensions are 480, 640, and most recently 1000, which Stockholm was the first city in Europe to install (July 2012).

Multi-mode or single-mode

Fibers come in single-mode and multi-mode varieties. Multi-mode fibers have limited transmission capacity and are best suited for short distances and local installations such as in properties. The single-mode fibers used by Stokab have low attenuation (i.e. the light pulse is marginally weakened), support communication over long distances and enable very high transmission capacity.



Article written by Petra Dalunde