According to the Dell'Oro Group, even as the broader optical transport market sharply declined in the first quarter, the demand for 40 Gbps DWDM remained high. The number of 40 Gbps DWDM wavelength shipments grew nearly 60% year-over-year in 1Q12.The total WDM market grew 5% in 1Q12 to $1.7 billion with positive growth contribution from 40 Gbps and 100 Gbps wavelength shipments. 40 Gbps wavelengths contributed approximately 30% of the total WDM revenue in the quarter. The top five 40-Gig equipment manufacturers were Huawei, Ciena, Alcatel-Lucent, and NEC.