New Optical Amplifier

A research team at the Chalmers University of Technology in Sweden has come up with a new optical amplifier that can help boost the efficiency of back-haul optical networks, a move that could have a big impact on the overall economics of bandwidth.

As light waves (carrying data) travel through fiber, they tend to lose strength over certain distances. Network operators deploy optical amplifiers, as the name suggests, to amplify those light waves. In the mid-1990s, network operators would deploy special devices that would convert optical signals to electrical signals and then resend them forward. This would happen every 100 kilometers or so.

However, with time optics improved and the telecom madness of late 1990s helped usher in new technologies that pushed those distances farther. And now the folks at Chalmers have come up with phase-sensitive fiber-optic parametric amplifier, PSA which reduces the noise in the networks to 1 decibal. In comparison, a erbium-doped fiber amplifier has noise figure of around 3 decibals at best. In short, Chalmers’ new breakthrough is more efficient and allows optical signals to be sent over longer distances 4,000 kilometers as opposed to 1,000 kilometers – which in turn would make the cost of building and operating the networks cheaper.

    “This is the ultimate optical amplifier. It enables connecting cities, countries and continents more efficiently by placing the amplification hubs at much greater intervals. The signal can also be modulated more effectively. In addition, the amplifier is compatible with any modulation format, with traditional laser transmitters and can be very broadband, making it compatible with many lasers at different wavelengths”, says Professor Peter Andrekson, who has developed the low-noise amplifier together with his research group in fiber optics.

    The group has taken advantage of the fact that the refractive index of glass is not constant, but dependent on light intensity in the fiber. The new amplifier shows experimentally to have 1 dB noise level, with a theoretical minimum of 0 dB, i.e. no noise being added in the amplification process. The next step for the Chalmers researchers are towards applications.

    “The entire optical telecom industry is our market. But the technology is generic, and scalable to other wavelengths like visible or infrared light, which makes it attractive in areas such as measurements, spectroscopy, laser radar technology and any applications where detection of very weak levels of light is essential”, says Peter Andrekson. (Chalmers press release.)

So why should we be very excited about this breakthrough? We are spending more time, doing more things on the Internet and that fundamentally is an irreversible trend. Whether it is us or our machines it is hard to imagine a future that in un-connected.