Tags:
Ethernet standard originally relied on duplex fiber cabling with each channel using one fiber to transmit and the other to receive. But according to the 802.3ab standard, When transition to 40/100G, parallel optics are needed to transmit and receive signals. Because for 40G, there are 4-Tx and 4-Rx fibers, each transmitting at 10G for an aggregate signal of 40G. Parallel optics represent a type of optical communication technology as well as the devices on either end of the link that transmit and receive information which are also known as parallel optical transceivers. For 40G parallel optics, there are 40GBASE-SR4 and 40GBASE-CSR4 transceivers. This article will highlight some practical solutions to the cabling connectivity for 40G parallel optical transceiver.
To realize 40G connectivity, 40G parallel optical transceivers typically use four 10G channels to transmit and four 10G channels to receive over one 12-fiber assembly. The middle four fibers remain unused, or dark. Each fiber either transmits (Tx) or receives (Rx) 10G traffic at a single wavelength. 40G QSFP+ transceiver because of its smaller size and high performance becomes the dominant transceiver module for 40 Gigabit Ethernet applications. 40GBASE-SR4 parallel optics solution for MMF was released by IEEE standard 802.3ba in 2010. Since then, some other engineered solutions have been released, including 40GBASE-CSR4, which is similar to 40GBASE-SR4 but extends the distance capabilities.
40GBASE-SR4 QSFP modules primarily enable high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multi-fiber female connectors. It can support link lengths of 100 meters and 150 meters over laser-optimized OM3 and OM4 multimode fibers respectively. Take FTL410QE2C as an example, it is Finisar 40GBASE-SR4 QSFP+ that can be used to connect with four 10GBASE-SR optical interfaces using an 8-fiber MTP to 4 duplex LC cable.
40GBASE-CSR4 QSFP modules can be used for native 40G optical links over 12-fiber parallel cables with MPO/MTP female connectors or in a 4x10G mode with parallel to duplex fiber breakout cables for connectivity to four 10GBASE-SR interfaces. It can extend the reach of 40GBASE-SR4 interface to 300 and 400 meters over laser-optimized OM3 and OM4 multimode parallel fibers.
To connect a parallel optics 40 Gigabit Ethernet transceiver to another 40 Gigabit Ethernet transceiver, a Type-B female MPO/MTP to female MPO/MTP cable is required. The following figure shows two QSFP+ transceivers being connected with an MTP female cable. The fiber position is reverse on the ends of the assembly. This reverse fiber positing allows the signal to flow from transmission on one end of the link to reception on the other end. This type of direct connectivity is only suggested for short distances within a given row of racks/cabinets. It has less robustness (less tensile strength, less crush and impact resistance, etc.) than a distribution-style cable, which would be used for structured cabling trunks.
In addition, there are some other cabling solutions for parallel optics 40G connectivity. First, in the interconnect structured cabling system, MTP Trunk cables will be deployed by placing them in cable trays without the fear of the trunk cable being crushed. Second, with 2×12 to 3×8 or 1×24 to 3×8 harness assembly, 100% fiber utilization will save the cost of fiber utilization in the structure cabling. And it also saves the cost of deploying labor and materials. Make sure that each MTP connector is plugged into a port. Last but not least, this approach uses 40G channel interconnect structured with conversion devices: 2×3&1×3 modules. It can utilize 100% of the installed fiber as harnesses. It is easily accomplished by using Type-B non-pinned MTP to non-pinned MTP jumpers.
Many research company says that 40G parallel optical communication will be the trend in the near future. And to connect a QSFP+ to QSFP+, a MTP 12-fiber trunk cable. Are usually used. Fiberstore provides various types of 40GbE transceivers such as MPO/MTP trunk cable, MPO/MTP harness cable, MPO/MTP cassette and other assemblies for your 40G network connectivity. All of our products are well-tested to ensure our customers to receive the optics with superior quality.