40GBASE-SR4(short range) is a port type for multimode fiber and uses 850 nm lasers. Its Physical Coding Sublayer 64b/66b PCS is defined in IEEE 802.3 Clause 82 and its Physical Medium Dependent PMD in Clause 86. It uses four lanes of multimode fiber delivering serialized data at a rate of 10.3125 Gbit/s per lane. 40BASE-SR4 has a reach of 100m on OM3 and 150m on OM4. There is a longer range variant 40BASE-eSR4 with a reach of 300m on OM3 and 400m on OM4. This extended reach is equivalent to the reach of 10GBASE-SR.
40GBASE-SR4 operates at 850nm wavelength wavelength using 4×10Gbps paralled transmission over parallel ribbon cable with MPO connectors. Fou multimode fibers, each operating at 10Gbps, are used to transmit 40Gbps in each direction of a duplex link for a total of 8 fibers(4 fibers to transmit in one direction and 4 fibers to transmit from the other direction). These links use ribbon cables or loose tube cable, which are made into a ribbon at the ends of the cable or broken out to an LC(or SC)/MPO breakout cable system. Twelve-five ribbons terminated to a 12-fiber MPO connector are used for each duplex link; however,only 8 fibers out of the 12 are actively used.
The standard supports two multimode fiber types and link distances:100 meters, over OM3 50/125 micron multimode fiber. This fiber, standardized in TIA-492-AAAAC-A, is called 850nm laser-optimized 50/125 micron multimode fiber. The standard aslo supports 150 meters over OM4 50/125 micron multimode fiber. OM4 fiber is standardized in TIA-492-AAAD. These links use QSFP and CFP optical modules.
Most new structured cabling installations use 0M3 and OM4 multimode fiber since it is optimized for use with low-cost 850nm-based optics, and since they are the only multimode types standardized for 40 and 100Gbps Ethernet operations. Low-bandwidth 62.5/125 micron (OM1) and 50/125 micron OM2 multimode fiber do not support 40 and 100Gbps Ethernet operation, and therefore deployments of these fiber types are decreasing over time. Since 40GBASE-SR4 uses low-cost 10GBase-SR like 850nm VCSEL lasers, 40GBASE-SR4 delivers the lowest cost, lowest power, and smallest from-factor optical modules.
Similar to 40 GbE,100 GbE uses electrical lanes of 10Gbps with sc Rambled encoding to create 100Gbps links.100GBASE-CR10 supports links up to 7 meters over 10 pairs of Copper wires in each direction in a jumper cable assembly.100GBASE-SR10 is an optical link that uses Short wavelength lasers with 10 parallel fibers in each direction and supports Short Reach link distances up to 100 meters on OM3 fiber or 150 meters over OM4 fiber on engineered links.
100GBASE-SR10 operates at 850nm wavelength using 10×10Gbps parallel transmission over parallel ribbon cable with MPO connectors. Ten multimode fibers, each operating at 10Gbps, are used to transmit 100Gbps in each direction of a duplex link for a total of 20 fibers(10 fibers to transmit in one direction and 10 fibers to transmit from the other direction). Similar to 40GBASE-SR4, these links use ribbon cables or loose tube cables terminated to 24-fiber MPO connetors;however, only 20 fibers out of the 24 are actively used.
The standard supports two multimode fiber types and like distances:100 meters,over OM3 50/125 micron multimode fiber and 150 meters over OM4 50/125 micron multimode fiber. Low-bandwidth 62.5/125 micron OM1 and 50/125 micron OM2 multimode fiber do not support 40and 100 Gbps Ethernet operation. These links use CXP and CFP optical modules.
Since 100GBASE-SR10 uses low-cost 10GBase-SR like 850nm VCSEL lasers, 100GBASE-SR10 delivers the lowest cost, lowest power, and smallest form-factor optical modules for 100Gbps operation.