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Light Peak

A New Optical Technology For Connecting PC Peripherals And Consumer Electronics


Light Peak Module

Light Peak Module


The primary interconnect between devices in the computer world have relied upon wires to carry electrical signals. This has worked extremely well over the years as copper and silicon were fairly common and easy to work with. There are limitations to using electrical signals for carrying information between devices though. Because of this the computer industry is reaching the limits of what can be achieved through electrical signaling. As a result, several companies including Intel and Apple are looking at an alternative method through a new interconnect called Light Peak.

What is Light Peak?

Light Peak is a new peripheral interface technology that allows computers to connect peripheral devices or other computers via an optical connector. Optical technology isn't new. It has been used for years by telecom companies for networking. Light is a much more efficient method for transmitting large amounts of data over large distances. The problem is that the optical modules that converted the electrical signals to optical were extremely expensive and large. With new technology, it is now possible to create the optical modules that are compact and affordable for more widespread use.

Optical vs. Electrical Cables

The main advantage of Light Peak is the use of optical cabling versus electrical cabling. Carrying electrical signals over copper wire at distance has its issues. As the length of distance increases and the speed increase, the amount of distortion in the signal becomes greater. Eventually, the interference becomes too great that the signal can not be reliably transmitted between the computer and peripheral. This is why there are fixed peripheral cable lengths.

Optical signals don't have these same issues of interference. This means that the cables can extend to much greater distances than copper wire. The optical fibers are also much thinner allowing for more flexible cabling than copper wire bundles. A standard Light Peak optical cable is about the width of a single strand of human hair. These cables could be extended to a length of up to 100 meters which will effectively reach anywhere within a household and far enough for most businesses.

Light Peak Vs. USB 3.0

USB 3.0 has been available to the market for some time but hasn't really caught on much with personal computers. Much of this was because of Intel's choice to not include it in their chipsets for laptops and desktops. With the introduction of Light Peak coming sometime in 2011, there is naturally going to be competition and comparison between the two standards.

The major advantage that Light Peak will bring over USB 3.0 is speed. USB 3.0 is rated at a maximum speed of 4.8 Gbps. The initial release of Light Peak is expected to bring over double that speed with a 10Gbps transfer rate. Supposedly the standard can be improved to allow speeds up to 100Gbps which would be roughly twenty times that of USB 3.0.

With so much bandwidth over the optical cables, Light Peak also brings the ability to transfer multiple protocols over a single fiber connectors. USB 3.0 has the ability to run multiple devices over a single cable set to a hub but Light Peak goes beyond this. A great example of this would be using Light Peak to connect a PC to a monitor via a single fiber cable. That cable could carry a digital video signal to the monitor and still have the ability to carry the bandwidth to allow that same monitor to also provide full speed USB 3.0 ports on the monitor.

The big disadvantage to Light Peak is compatibility. USB 3.0 is backward compatible with USB 2.0 which is the most widespread interface for computer peripherals. Light Peak would require a completely new set of peripheral devices to take full advantage of the interconnects speed and capabilities. While the modules are supposed to be relatively inexpensive, the peripheral companies would have to completely reengineer their devices to use the new standard. With USB technology being so prevalent, it will be a huge obstacle for its acceptance.


Light Peak offers new levels of performance and capabilities for both computers and consumer electronics. The extremely high data rates are well beyond what is capable with existing electrical methods and the potential for integrated cables can make cabling between devices much easier. Acceptance of the new technology is going to be its major obstacle. With consumers so heavily invested in USB peripherals, the requirement of all new peripherals to take advantage of the technology means that it will take several years before it has the chance of really being used by the average consumer. Instead, it will likely be used by workstation classed computers within businesses with high high data rate requirements.

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