New fibres carrying ‘twisted light’ reach terabit speeds

28 June 2013
By Edd Gent
Mobile version
Share |
Transmitting

Transmitting "twisted light" down fibre optic cables can boost internet speeds to more than 1 terabit per second

A new kind of optic fibre that can carry “twisted light” could provide internet speeds of over a terabit a second.

The technology relies on donut-shaped laser light beams called optical vortices, or orbital angular momentum (OAM) beams, in which the light twists like a tornado as it moves along the beam path rather than in a straight line.

Optical vortices were previously thought to be unstable in optical fibre, but Boston University (BU) Engineering Professor Siddharth Ramachandran has now designed a fibre capable of propagate them.

In a paper appearing in today’s issue of journal Science, he and Alan Willner of University of Southern California (USC) demonstrate not only the stability of the beams in optical fibre but also their potential to boost internet bandwidth.

"For several decades since optical fibres were deployed, the conventional assumption has been that OAM-carrying beams are inherently unstable in fibres," says Ramachandran.

"Our discovery, of design classes in which they are stable, has profound implications for a variety of scientific and technological fields that have exploited the unique properties of OAM-carrying light, including the use of such beams for enhancing data capacity in fibres."

Traditionally, bandwidth has been enhanced by increasing the number of colours, or wavelengths of data-carrying laser signals – essentially streams of 1s and 0s – sent down an optical fibre, where the signals are processed according to colour.

Increasing the number of colours has worked well since the 1990s when the method was introduced, but now that number is reaching physical limits.

An emerging strategy to boost bandwidth is to send the light through a fibre along distinctive paths, or modes, each carrying a cache of data from one end of the fibre to the other.

Unlike the colours, however, data streams of 1s and 0s from different modes mix together; determining which data stream came from which source requires computationally intensive and energy-hungry digital signal processing algorithms.

Ramachandran's and Willner's approach combines both strategies, packing several colours into each mode, and using multiple modes.

Unlike in conventional fibres, OAM modes in these specially designed fibres can carry data streams across an optical fibre while remaining separate at the receiving end.

In experiments appearing in the Science paper, Ramachandran created an OAM fibre with four modes (an optical fibre typically has two), and he and Willner showed that for each OAM mode, they could send data through a one-kilometre fibre in 10 different colours, resulting in a transmission capacity of 1.6 terabits per second, the equivalent of transmitting eight Blu-Ray DVDs every second.

The research is the result of collaboration between optical fiber experts at BU and optical communication systems experts at USC and Ramachandran and Willner also collaborated with OFS-Fitel, a fibre optics company in Denmark, and Tel Aviv University.

"Siddharth's fibre represents a very unique and valuable innovation. It was great to work together to demonstrate a terabit-per-second capacity transmission link," says Willner, electrical engineering professor at the USC Viterbi School of Engineering.

Latest Issue

E&T cover image 1605

"We visit Barcelona, one of the smartest cities in the world, to find out what makes it so special. What does it look like and what is the future?"

E&T jobs

  • High Voltage Engineer

    Premium job

    Essex X-Ray & Medical Equipment
    • Great Dunmow, Essex

    This High Voltage Engineer will provide design leadership for high voltage cable assemblies up to one megavolt.

    • Recruiter: Essex X-Ray & Medical Equipment

    Apply for this job

  • Sales Electronics Engineer

    Premium job

    Precision Microdrives
    • London (Greater)
    • £25,000 - £30,000 starting salary, inclusive of on-target commissions.

    Precision Microdrives (PMD) is a fast growing technology company that designs, produces and trades miniature electro-mechanical mechanisms

    • Recruiter: Precision Microdrives

    Apply for this job

  • Senior Development Engineer, Electronics

    Premium job

    Helmet Integrated Systems / Gentex Corporation
    • Letchworth Garden City, Hertfordshire
    • Competitive

    We are innovative, robust and fast growing business, whose main focus is to deliver continues improvement to existing products and offer new soluti...

    • Recruiter: Helmet Integrated Systems / Gentex Corporation

    Apply for this job

  • Analogue Electronics Engineer

    Premium job

    Swedish Institute of Space Physics (IRF)
    • Uppsala (Stad) (SE)

    The Swedish Institute of Space Institute (IRF) in Uppsala search for an analogue electronics engineer.

    • Recruiter: Swedish Institute of Space Physics (IRF)

    Apply for this job

  • Principal Robotic Systems Engineer

    Premium job

    National Oceanographic Centre
    • Southampton, Hampshire
    • £45,271 to £49,207 per annum

    Responsible for technical oversight and project management of internally and externally funded innovation centre projects.

    • Recruiter: National Oceanographic Centre

    Apply for this job

  • Smart Grid Research Engineer

    Premium job

    University of Strathclyde
    • Cumbernauld, Glasgow
    • Grade: 6/7* £26,537 - £37,768*

    Work as part of a growing dynamic team on a wide range of technical projects with particular emphasis on experimental validation and testing

    • Recruiter: University of Strathclyde

    Apply for this job

  • Electrical Engineer - Water

    Premium job

    Mott MacDonald
    • Peterborough, Cambridgeshire

    Mott MacDonald's highly successful Water and Environment Unit is recruiting an electrical engineer....

    • Recruiter: Mott MacDonald

    Apply for this job

  • Electrical Design Engineer

    Premium job

    Mott MacDonald
    • Cambridge, Cambridgeshire

    Mott MacDonald's highly successful water business continues to win and deliver a fantastic amount of work....

    • Recruiter: Mott MacDonald

    Apply for this job

  • Launcher Verication & Validation Lead

    MBDA
    • Bristol
    • Competitive Salary & Benefits

    What’s the opportunity? Opportunity to join a very dynamic, responsive and multinational Launcher team, focussed on rapid development, proving and manufacture to meet challenging programme...

    • Recruiter: MBDA

    Apply for this job

  • Technical Design Authority - Marine Systems (Mechanical)

    BAE Systems
    • Scotland, Glasgow
    • Negotiable

    Technical Design Authority - Marine Systems (Mechanical) Would you like to play an exciting and varied role working with the River Class Batch 2 (RCB2) vessels for the Royal Navy? We currently have a vacancy for a Technical Design Authority - Marine Syste

    • Recruiter: BAE Systems

    Apply for this job

More jobs ▶

Subscribe

Choose the way you would like to access the latest news and developments in your field.

Subscribe to E&T