New tunable filter to provide high speed internet

Scientists have developed a new filter with the widest tuning span ever demonstrated on a silicon chip that could help provide the low-cost flexibility needed for next generation of high-speed optical networks.
The path towards a faster internet has been hindered by energy consumption and cost per optical component, said Wei Shi, Assistant Professor from Universite Laval in Canada.
Researchers have designed a tunable filter - an important component of high-capacity optical networks - that should save both money and energy because it can be readily integrated onto a photonic chip.
The filter's tuning span, which is a measure of how well the device can adjust to fluctuating data demands, is the widest ever demonstrated on a silicon chip.

The device has an unlimited free-spectral range, meaning it can operate over any range of frequencies.
"The most exciting aspect is that these record-breaking results were achieved on the silicon photonic platform," Shi said.

"This indicates that the filter can be readily integrated with other well developed components for a novel integrated system," said Shi.
The next-generation of internet technology could mean videos that stream in 3D or 360 degrees and vast amounts of cheap cloud data storage.
As internet traffic has increased dramatically, bandwidth has become more precious, researchers said.
To maximise the power and cost efficiency, optical networks must be able to flexibly allocate bandwidth, giving each customer only what they need at any given time.

Flexible networks require tunable filters. Filters isolate a specific communication channel from all the others.
Tunable filters give a network controller the freedom to select the frequency and bandwidth for each channel and change them on the fly.
The tunable filter that the researchers designed and tested has a tuning span of 670 GHz, much greater than the approximately 100 GHz span of current silicon-based filters.
The researchers believe that with further modification their device's tuning span can be further extended, to 1 THz.
The device works by using periodic nanostructures, 10,000 times smaller than the width of a human hair, to separate the different frequencies of light from each other.

The filter tuning is achieved with micro-heaters in the silicon chip that control the local temperature, which in turns affects the nanostructures and the frequencies they separate.
* Globally, 5.2% of unique IP addresses connected to Akamai
at average speeds of at least 25 Mbps, a 6.3% increase over the previous quarter. Year-over-year, global 25 Mbps adoption increased by 15%, in contrast to the 0.5% yearly decrease seen in the second quarter.
* Three of the top 10 countries/regions - South Korea (24% adoption), Hong Kong (14% adoption), and Japan (13% adoption) - saw yearly declines, losing 37%, 15%, and 2.5%, respectively.

* In the U.S., 10 states had 10% or more of unique IP addresses connected to Akamai at average speeds of at least 25 Mbps, with the District of Columbia holding the top spot at 22% adoption.
* The global percentage of unique IP addresses connecting to Akamai that met the 4 Mbps broadband speed threshold increased 2.7% to 65%. Year-over-year growth was 9.8%. * In the third quarter of 2015, 27% of unique IP addresses across the world connected to Akamai at average speeds above 10 Mbps, an increase of 2.4% over the previous quarter. Year-over-year, this was a 19% increase. * 15% percent of the unique global IP addresses connected to Akamai at average "4K-ready" connection speeds of 15 Mbps or above, up 5.3% from the second quarter. Year-over-year, the global 15 Mbps adoption rate grew 21% with seven of the top 10 countries/regions seeing gains ranging from 8.9% in Latvia (31% adoption) to 73% in Norway (37% adoption). IPv4 and IPv6

* Partially offsetting the second-quarter drop, the number of unique, worldwide IPv4 addresses connecting to Akamai increased by about 4.8 million in the third quarter. * The U.K. Saw IPv4 counts hold steady, while the U.S. Saw a small 0.5% decline from the second quarter. * On a global basis, close to 60% of the countries/regions saw a quarter-over-quarter increase in unique IPv4 address counts in the third quarter, compared with roughly half in the second quarter
* 43 countries/regions saw IPv4 address counts grow 10% or more, while 27 saw counts decline 10% or more as compared with the previous quarter.

* European countries continued to dominate the top 10 countries/regions, taking eight of the top 10 spots with the largest percentage of content requests made to Akamai over IPv6 in the third quarter of 2015.