Development of world's highest-density optical fiber cable

Jul 04, 2012

Nippon Telegraph and Telephone Corporation has developed the world’s highest-density multi-fiber optical fiber cable for outdoor optical fiber networks. NTT Access Network Service Systems Laboratories (NTT Labs) succeeded in increasing to an ultimate fiber density of optical fiber cable by using bending loss insensitive optical fiber (BIF) and novel optical fiber ribbon.

This cable will be come into practical use in Nippon Telegraph and Telephone East Corporation (NTT East) and Nippon Telegraph and Telephone West Corporation (NTT West) in late July, 2012. The lighter-weight and smaller-diameter optical fiber cable due to increase in its fiber density will be expected to contribute to improvement of the installation workability and effective use of infrastructure will be expected.

Optical fiber cable is required to have smaller diameter and lighter weight as well as stable transmission loss characteristics and mechanical characteristics. Usually, outdoor optical fiber cable is installed over several hundred meters. Lighter-weight of optical fiber cable enables improving in the workability of installation, e.g. manual installation without towing machines or installation by fewer workers. Also, smaller diameter of optical fiber cable enables the effective use of available space to install optical fiber cable such conduits. To expand the spread of FTTH service, NTT Labs. has been developed the optical fiber cable with smaller diameter, lighter weight and higher density to achieve effective construction of the optical fiber network.

Figure.2: World’s highest density optical fiber cable

NTT Labs has developed the world’s highest-density optical fiber cable that uses BIF and a novel optical fiber ribbon that we call “rollable optical fiber ribbon”. This cable is composed rollable optical fiber ribbon which standard 0.25mm diameter coated optical fibers are intermittently bonded in a longitudinal direction. By deploying this optical fiber cable to aerial and a part of conduit area as shown in Fig. 1 , it can achieve effective construction of optical fiber network. This cable has 30% smaller diameter and 60% lighter weight than conventional slotted rod type optical fiber cable as shown in Fig. 2.

Optical fiber cables should be designed to allow stable loss characteristics and mechanical characteristics in the presence of external forces as bending, tension and compression. In a conventional optical fiber cable, it is necessary to protect optical fiber from such external forces by slotted rod or buffer layer.

(1) Densely assembling technologies using BIF

The optical fibers should be tightly bundled as much as possible to realize the extremely smaller-diameter and lighter-weight optical fiber cable. However, it has been difficult to suppress the optical loss increase caused by micro bending force in cable when using conventional optical fibers. In this new developed optical fiber cable, stable transmission loss characteristics can be realized by using BIF which has an improved bending performance.

(2) Rollable optical fiber ribbon technologies (Fig.3)

When we construct optical network, mass-splicing of the optical fiber is required for efficient fiber connection. Therefore, optical fiber ribbons are widely used. However, they have less flexibility depending on bending direction, and so they will cause a large fiber strain when these are tightly assembled. This is because the fiber ribbons in the cables will be bent within their plane surfaces. A novel optical fiber ribbon is composed of four single fibers that are arranged linearly and neighboring fibers are fixed together periodically. This structure enables the ribbon to be rolled up easily in optical fiber cable. Therefore, this ribbon can be accommodated very tightly in the cable. Also, this ribbon can be mass-spliced as same as conventional optical fiber ribbon.

Figure.3: Rollable optical fiber ribbon

To further expand the spread of broad-band services, we will continue investigating the optical fiber cable structure according to other application areas of optical fiber networks.

Explore further: Lifting the brakes on fuel efficiency

add to favorites email to friend print save as pdf

Related Stories

Ad watchdog: Cablevision Internet not 'fastest'

Mar 27, 2009

(AP) -- Cablevision Systems Corp. should stop saying its Internet service is "the fastest around," the advertising industry's self-regulatory body said Thursday, in response to complaints from competitor Verizon Communications ...

Fiber Optical Transmission In Demand Of Higher Capacity

Apr 02, 2010

( -- With the increasing high volume content over the internet, such as multimedia and high definition images, new transmission methods need to be found to handle the increasing data demand. Nippon ...

Recommended for you

Lifting the brakes on fuel efficiency

Apr 18, 2014

The work of a research leader at Michigan Technological University is attracting attention from Michigan's Governor as well as automotive companies around the world. Xiaodi "Scott" Huang of Michigan Tech's ...

Large streams of data warn cars, banks and oil drillers

Apr 16, 2014

Better warning systems that alert motorists to a collision, make banks aware of the risk of losses on bad customers, and tell oil companies about potential problems with new drilling. This is the aim of AMIDST, the EU project ...

User comments : 0

More news stories

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

A homemade solar lamp for developing countries

( —The solar lamp developed by the start-up LEDsafari is a more effective, safer, and less expensive form of illumination than the traditional oil lamp currently used by more than one billion people ...

Floating nuclear plants could ride out tsunamis

When an earthquake and tsunami struck the Fukushima Daiichi nuclear plant complex in 2011, neither the quake nor the inundation caused the ensuing contamination. Rather, it was the aftereffects—specifically, ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...