40G QSFP+ transceiver is a hot-swappable module, integrating 4 independent 10Gbps data lanes in each direction for 40Gbps aggregated bandwidth. QSFP+ modules offer customers a wide variety of high-density 40Gbps connectivity options for data center, high-performance computing networks, enterprise core and distribution layers, and service provider transport applications. The release of the IEEE 802.3ba physical layer standard for 40G QSFP+ in 2010 specifies both fiber and copper cabling solutions, such as 40GBASE-SR4, 40GBASE-LR4 and 40GBASE-CR4.
Commonly used QSFP+ transceiver port types are 40GBASE-SR4 and 40GBASE-LR4.
40GBASE-SR4 physical medium dependent (PMD) variant defines a 4 lane parallel optical interconnect for operation up to 100m link length over OM3 multi-mode fiber (MMF) and to 150m over OM4 MMF. It establishes high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multi-fiber female connectors. Four of the twelve fiber for receive, other four for transmit, leaving the middle four fiber unused. Each of the four lanes operates at a data rate of 10.3125Gbps which is the same serial bit rate that was defined for 10Gb Ethernet links in the IEEE 802.3ae standard ratified in 2002.
40GBASE-LR4 has two link options: coarse wavelength division multiplexing (CWDM) and parallel single-mode fiber (PSM). This passage mainly talks about the first one option.
IEEE has specified standards for 40G transmission in both long distance and short distance, which are 40GBASE-SR4 and 40GBASE-LR4. As what has been mentioned above, the latter is sested for 40G transmission over SMF in long distance up to 10km, while the former is for 40G transmission in short distance over MMF (often in with a 12-fiber MPO connector version)—OM3 (up to 100 meters) and OM4 (up to 150 meters). OM3 and OM4, which are usually aqua-colored, are accepted economic solutions for 40G in short distance with lower insertion loss and higher bandwidth. Besides, DACs are also chosen as the 40G cabling solutions sometimes, available in QSFP+ to QSFP+ DAC and QSFP to SFP+ cable versions.
40G QSFP+ transceivers support 40GBASE Ethernet, allowing flexibility of interface choice and great bandwidth for data centers. For your smooth 40GbE performance, fiber-mart supplies various cost-effective QSFP+ transceivers which are fully compatible with major brands, such as Cisco, Juniper, Brocade, and so on. Besides these 40G modules, SFP transceivers are also offered, like Cisco GLC-T, a Cisco compatible 1000BASE-T SFP. All these products are rigorously checked for quality and compatibility assurance. If you want such a module for your networking use, you can consider fiber-mart.