Li—Fi來襲：開盞LED燈上網去

A microchipped bulb can produce data speeds of up to 150 megabits per second （Mbps）， Chi Nan， IT professor at Shanghais Fudan University said.

A one-watt LED light bulb would be enough to provide net connectivity to four computers， researchers said.

But experts told the BBC more evidence was needed to back up the claims. There are no supporting video or photos showing the technology in action.

上海復旦大學信息技術學院遲楠教授表示，一個微芯片燈泡可以產生高達150MB每秒的網速。

研究者還表示，一個1瓦的LED燈泡已經足以為四臺電腦提供網絡連接。

不過專家也告訴BBC記者，佐證上述說法需要更多的信息。目前還沒有證實該技術成功運用的視頻或照片。

Li-fi， also known as Visible Light Communications （VLC）， at these speeds would be faster and cheaper than the average Chinese broadband connection.

In 2011， Prof Harald Haas， an expert in optical wireless communications at the University of Edinburgh， demonstrated how an LED bulb equipped with signal processing technology could stream a high-definition video to a computer.

He coined the term “light fidelity” or li-fi and set up a private company， PureVLC， to exploit the technology.

In 2013， the Fraunhofer Heinrich Hertz Institute claimed that data rates of up to 1Gbit/s per LED light frequency were possible in laboratory conditions， making one bulb with three colours potentially capable of transmitting data at up to 3Gbit/s.

Li-fi promises to be cheaper and more energy-efficient than existing wireless radio systems given the ubiquity of LED bulbs and the fact that lighting infrastructure is already in place.

Visible light is part of the electromagnetic spectrum and 10，000 times bigger than the radio spectrum， affording potentially unlimited capacity. But there are drawbacks： block the light and you block the signal.

Li-Fi，光保真，又稱為可見光通信（VLC），將會比中國一般的寬帶網絡連接速度更快，且價格更便宜。

在2011年，來自英國愛丁堡大學的光無線通信專家，哈拉爾德·哈斯教授，演示了一只配備有信息處理裝置的LED燈泡是如何將高保真視頻傳輸到電腦上的。

他創造了“光保真”這一術語，并且成立了一家私營公司PureVLC來進一步開發這種技術。

2013年，德國弗朗霍夫海因里希赫茲研究所稱，在實驗室環境下，一個LED燈泡的數據傳送速率達到1GB每秒已經成為可能，這樣一個三色的燈泡傳達數據的速度將可以達到3GB每秒。

考慮到LED燈泡的普遍性，而且照明基礎設施是既有的，光保真將比現有的無線廣播系統更加節能，更加環保。

可見光是電磁光譜的一部分，比無線電頻譜要大1萬倍，因而可說具有無限的開發潛力。但是它也有弊端：遮住光源，就遮住了信號。