Separate signals through optical fibres for ultrafast home network

Jan 24, 2008

Dutch-sponsored researcher Christos Tsekrekos has investigated how a small network for at home or in a company can function optimally. His research analyses the MGDM technique (Mode Group Diversity Multiplexing) of the Eindhoven University of Technology.

This technique transmits each TV, telephone and Internet signal via a separate group of light rays through the optical fibre cable. Such a technology has not yet been marketed. Yet in the ideal situation it could be applied in a glass or polymer fibre, has the potential of being cheap, and transmits all information without disruption.

Existing systems for small networks at home or in a company make use of multimode glass fibres or multimode polymer optical fibres (POF). The latter are relatively thick cables (about 1 mm thick, thus thicker than the glass fibre which is 0.125 um thick). Multimode fibre cables can conduct many light rays and can operate free of disruption and with a greater bandwidth than a wireless connection. However, due to a slight variation in the speed of the light rays through the multimode fibre, a signal transmitted by all of these rays becomes spread out. Consequently, the signals become broader and therefore fewer signals fit in the fibre, limiting the transmission capacity.

Independent channels

Tsekrekos investigated how the MGDM technique can increase the capacity of a multimode fibre network. He created independent channels by dividing the total group of light rays into groups of closely related light rays (or modes). Using special optical and electrical techniques, Tsekrekos investigated how the crosstalk between these groups could be eliminated so as to render these groups independent of each other.

This step allows several groups to be used in parallel, thereby increasing the fibre's capacity. Moreover, each group can transport its own type of signal, which means that TV, telephone and Internet signals can be transmitted though the same fibre.

Using this approach the researcher constructed a simple yet stable MGDM system. The system works well up to distances of 1 km of multimode glass fibre with a core diameter of 62.5 um. Tsekrekos invented a new mode-selective spatial filter (MSSF), based on lenses with specific characteristics, to make the system reliable and to allow a large number of channels to be realised. This can result in a stable and transparent five-channel MGDM system.

Philips, Draka Fibre, TNO-ICT, and several electrical contractors are supervising this project in the Technology Foundation STW users' committee. Philips and TNO-ICT are very interested in home networks that can flexibly transport a wide range of signals.

The MGDM technology together with thick multimode glass or polymer fibres will soon make it possible for consumers to simply install a universal and high capacity broadband network at home. Draka Fibre (in Eindhoven) considers the MGDM technology to be a highly promising means of obtaining even more capacity and possible applications out of this type of fibre. Further research should lead to a greater increase of the multiplex factors in more complex network structures.

Source: NWO

Explore further: Quantenna promises 10-gigabit Wi-Fi by next year

add to favorites email to friend print save as pdf

Related Stories

More, bigger wildfires burning western US, study shows

33 minutes ago

Wildfires across the western United States have been getting bigger and more frequent over the last 30 years – a trend that could continue as climate change causes temperatures to rise and drought to become ...

Thinnest feasible nano-membrane produced

1 hour ago

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

Clean air: Fewer sources for self-cleaning

1 hour ago

Up to now, HONO, also known as nitrous acid, was considered one of the most important sources of hydroxyl radicals (OH), which are regarded as the detergent of the atmosphere, allowing the air to clean itself. ...

Recommended for you

Hand out money with my mobile? I think I'm ready

3 hours ago

A service is soon to launch in the UK that will enable us to transfer money to other people using just their name and mobile number. Paym is being hailed as a revolution in banking because you can pay peopl ...

Quantenna promises 10-gigabit Wi-Fi by next year

Apr 16, 2014

(Phys.org) —Quantenna Communications has announced that it has plans for releasing a chipset that will be capable of delivering 10Gbps WiFi to/from routers, bridges and computers by sometime next year. ...

Tech giants look to skies to spread Internet

Apr 16, 2014

The shortest path to the Internet for some remote corners of the world may be through the skies. That is the message from US tech giants seeking to spread the online gospel to hard-to-reach regions.

Wireless industry makes anti-theft commitment

Apr 16, 2014

A trade group for wireless providers said Tuesday that the biggest mobile device manufacturers and carriers will soon put anti-theft tools on the gadgets to try to deter rampant smartphone theft.

Dish Network denies wrongdoing in $2M settlement

Apr 15, 2014

The state attorney general's office says Dish Network Corp. will reimburse Washington state customers about $2 million for what it calls a deceptive surcharge, but the satellite TV provider denies any wrongdoing.

Netflix's Comcast deal improves quality of video

Apr 14, 2014

Netflix's videos are streaming through Comcast's Internet service at their highest speeds in the past 17 months now that Netflix is paying for a more direct connection to Comcast's network.

User comments : 0

More news stories

Tiny power plants hold promise for nuclear energy

Small underground nuclear power plants that could be cheaper to build than their behemoth counterparts may herald the future for an energy industry under intense scrutiny since the Fukushima disaster, the ...

Turning off depression in the brain

Scientists have traced vulnerability to depression-like behaviors in mice to out-of-balance electrical activity inside neurons of the brain's reward circuit and experimentally reversed it – but there's ...

Is Parkinson's an autoimmune disease?

The cause of neuronal death in Parkinson's disease is still unknown, but a new study proposes that neurons may be mistaken for foreign invaders and killed by the person's own immune system, similar to the ...