Bandwidth requirements have led to an explosive growth in hyperscale datacenters. Cisco predicts that by 2020 global cloud IP traffic will meet or exceed 14 zettabytes. IP video traffic will account for 82 percent of all IP traffic. All this means that 100G and higher data centers are becoming the norm.

The 100G QSFP28 transceiver is an excellent form factor for use in datacenters owing to its small size, versatility and low power consumption. Short reach(SR4) transceivers employ 850nm VCSELs and transmit data up to 100m. The LR4 at 10km uses WDM technologies to achieve 100G transmission over four different wavelengths around 1310nm. The 100G PSM4 and CWDM4 modules were developed to bridge the gap between SR4 and LR4. The 100G PSM4 which uses parallel fiber architecture is a cost-effective solution for 500m data transmission.

The 100G PSM4 specification defines requirements for a point-to-point 100 Gb/s link over eight single mode fibers (4 transmit and 4 receive) of at least 500m, each transmitting at 25Gbps. Four identical and independent lanes are used for each signal direction. PSM4 incorporates a single laser and does not need costly MUX/DEMUX unlike the CWDM4. With an MTP interface, PSM4 modules can bus 100Gb/s point-to-point over 2km or can be broken out into dual 50Gb/s or quad 25Gb/s links for linking to servers, storage and other subsystems. The PSM4 module typically uses OS2 fiber.

100G PSM4 Structure

100G PSM4 Structure

100G CWDM4

100G CWDM4

From an optical transceiver module structure viewpoint, PSM4 can be more cost effective because of its lower component costs. However, when the link distance is long, PSM4 would be more expensive mainly because PSM4 uses 8 optical single-mode-fibers while CWDM4 uses only 2 optical single-mode-fibers.

Vitex offers full portfolio of 100G products from 100m to 40km. Vitex 100G PSM4 is also available with pigtail ends. The 100G PSM4 is a proven versatile transceiver that can save money in 100G deployments. Please contact us at info@vitextech.com if you have any questions.