The QSFP-40G-LR4-TOP is a 4x10G hot pluggable optical transceiver. The technology enables the integration of 4 transmitters, 4 receivers and an optical MUX/DeMUX into a small form factor package that delivers a 40 Gbps data link in a compact QSFP footprint. The optical connectivity is based on two SMF LC connectors, one for Tx and one for Rx. The Tx and Rx each consist of 4 10GB/s CWDM channels, whose wavelengths are in the 1300nm range. The QSFP-40G-LR4-TOP transceiver is designed for applications based on the IEEE 802.3ba 40BASE-LR4 standard of up to 10km reach.