Challenges with 40G Transceiver

Nowadays, the public tend to have higher requirements for optic transceiver modules. 40G transceiver is exactly conformed to the demands. The most common type is 40G QSFP+ transceiver. The QSFP+ is a compact, hot-pluggable transceiver used for data communications applications. It interfaces networking hardware to a fiber optic cable. The QSFP+ transceivers are designed to carry serial attached SCSI, 40G ethernet, QDR (40G) and FDR (56G) infiniband, and other communications standards. 40G QSFP+ transceiver delivers network speeds of up to 40Gbps that will satisfy the appetite of any application that requires increased bandwidth. Its features are as below.

 

Hot-swappable input/output device that plugs into a 40G Ethernet QSFP port Interoperable with other IEEE-compliant 40GBASE interfaces where applicable Certified and tested on QSFP 40G ports for superior performance, quality, and reliability High-speed electrical interface compliant to the IEEE 802.3ba standard QSFP Form factor, 2-wire I2C communication interface and other low-speed electrical interface compliant to SFF 8436 and QSFP Multisource Agreement (MSA) Although it has remarkable features, there are still some challenges with existing 40G transceiver.

 

Standard SR (short-reach) 10G and 40G transceivers use fundamentally different connectivity formats, requiring fiber cabling infrastructure to be redesigned and replaced. 10G SR transceivers operate over dual-fiber multimode fiber (MMF) with LC connectors, and 40G SR protocols, such as SR4 and CSR4, operate over MMF ribbon with MPO connectors. As a result, 40G MPO-based SR4 transceivers cannot reuse aggregation fiber infrastructure built for 10G connectivity.

 

Connector type is not the only concern. Whereas 10G SR transceivers require 2 fiber strands per 10G link, 40G SR4 and CSR4 transceivers require a theoretical minimum of 8 fiber strands, and often 12 fiber strands in practice. The reason for this requirement is that 40G SR4 and CSR4 transceivers use 4 parallel fiber pairs (8 fiber strands) at 10Gbps each for a total of 40G full duplex, as shown in below picture. Obviously, of the 12 fiber strands terminated by MPO-12 connectors, 8 fiber strands (4 fiber pairs) carry traffic and 4 fiber strands are unused.

 

40G transceiver

To economize trunk fiber in a structured cabling environment, a 2 x 3 MPO fiber conversion module could combine three SR4 links onto two 12-fiber ribbon cables. But even then the 40Gbps SR4 trunk still uses 8 fiber strands per link compared to 2 fiber strands in the case of 10G SR.

 

At best, the connector change and increased fiber density needed for SR4 require a significant cable plant upgrade, making it expensive and disruptive for customers to migrate from 10G connectivity to 40G connectivity in their existing data centers.

 

Faced with the challenges of 40G optical transceiver modules, fiber-mart.com produce and sell 40G QSFP+ transceiver with high quality and at reasonable price. If you need 10G, 40G and 100G fiber optical transceivers, fiber-mart.com will be your first choice.