NTT Research and Development 2012 Review of Activities

Overview

With a view to promoting optical broadband services, we are undertaking R&D for completely replacing copper telecommunications wire in multi-dwelling units (MDUs) by optical fiber. Specifically, we are working on in-building optical wiring technology for existing buildings. Indoor optical cable for restricted spaces that allows optical wiring through narrows spaces at doors and windows without the need to drill holes in walls.

Features

• This indoor optical cable for restricted spaces consists of a cord part and a sheet part applied to a small curved corner.
• Single-mode hole-assisted optical fibers (HAFs) have lower bending loss. The optical signal is effectively confined because the refractive index difference between silica and air is large.
• The iron wire of the sheet part, which is applied to restricted spaces at doors and windows, can remain bent. The sheet part can then be easily fixed by one-sided tape.
• Increasing the bending radius by using optical slant wiring can reduce bending loss and maintain reliability.

Application scenarios

• The indoor optical cables for restricted spaces enable optical broadband service to be provided in multi-dwelling units even when the owners do not permit holes to be drilled in the walls.
• We have developed single-mode HAF with lower bending-loss characteristics than those of ITU-T recommendation G.657.B3. We intend to promote optical broadband services using this optical wiring system.

• *1 IDF: Intermediate Distribution Frame, *2 ONU: Optical Network Unit, *3 MDF: Main Distribution Frame
  *4 FRP: Fiber Reinforced Plastic