According to a report by the Dell'Oro Group, worldwide DWDM equipment market revenues grew 19% to $7.3 billion in 2011, largely driven by demand for 40 and 100 Gbps transmission. Dell'Oro expects the total DWDM market, which includes both metro and long haul applications, to maintain strong growth in 2012 and to reach $8.0 billion.The Optical Transport report indicates that the DWDM market grew across all the regions with North America accounting for the highest revenue during the year. The combined market for 40 Gbps and 100 Gbps DWDM wavelengths grew more than 60%, contributing nearly one-third of the 2011 market revenues. The top three equipment manufacturers in terms of DWDM revenue share were Huawei, Ciena and Alcatel-Lucent, respectively.