The 40G QSFP+ LR4 is a transceiver module designed for 10km optical communication applications. The design is compliant with 40GBASE-LR4 of the IEEEP802.3ba standard. The module converts 4 inputs channels (ch) of 10Gb/s electrical data to 4 optical signals and multiplexes them into a single channel for 40Gb/s optical transmission. The central wavelengths of the 4 channels are 1310 nm as members of the wavelength grid defined in ITU-T G694.2.