Optical networks in metro areas are being affected by many factors, including whether to use SONET, WDM or Ethernet, as well as the services, such as IPTV, that will. <a href="http://www.nanotech-now.com/news.cgi?story_id=45817">http://www.nanotech-now.com/news.cgi?story_id=45817</a> Iranian researchers at Masjed Soleiman and Gorgan Branches of Islamic Azad University in cooperation with their.