SMF&MMF 40G QSFP+ Transceiver Overview
Upgrading from 10G to 40G is an inevitable trend but it is also very challenging. The potential for a reconfiguration of the physical layer of the network is based on the reduced reach of the OM3/OM4 multimode optics from 10GBASE-SR (300/400m) to 40GBASE-SR4 (100/150m). And the existing fiber optic cabling plant may also need to be upgraded, for the additional fiber count needed to support the IEEE-defined 40GBASE-SR4 parallel optics. These bring SMF&MMF 40G QSFP+ transceiver to the market. This post will give a brief introduction to SMF&MMF 40G QSFP+ transceiver.
Definition
We know that a fiber optic transceiver may either operate on multimode fiber (MMF) or single-mode fiber (SMF). For example, Cisco QSFP-40G-LR4 40GBASE-LR4 QSFP+ transceiver operates on single-mode fiber and Cisco QSFP-40G-SR4-S 40GBASE-SR4 QSFP+ transceiver operates on multimode fiber. However, an SMF&MMF 40G QSFP+ transceiver can be used with both MMF and SMF without the need for any software/hardware changes to the transceiver module or any additional hardware in the network. SMF&MMF 40G QSFP+ transceiver is based on IEEE defined 40GBASE-LR4 specifications and operates on the 1310nm band. It uses a duplex LC connector and supports distances up to 150 m over OM4 multimode fiber and up to 2km over single-mode fiber (different vendor may have different specifications).
This is usually accomplished by combining four 10G optical channels at different wavelengths (1270, 1290, 1310, and 1330 nm) inside the transceiver module to transmit and receive an aggregate 40G signal over a single pair of multimode or single-mode fibers. Presently, there are mainly two types of SMF&MMF 40G QSFP+ transceiver in the market, Arista QSFP-40G-UNIV universal QSFP+ transceiver and Juniper JNP-QSFP-40G-LX4 40GBASE-LX4 QSFP+ transceiver. These two types of SMF&MMF QSFP+ transceiver are widely installed and used for upgrading from 10G to 40G networks without modification or expansion. The picture below shows a Juniper JNP-QSFP-40G-LX4 compatible 40GBASE-LX4 QSFP+ transceiver.
Advantages
Migration to 40G for switch to switch connections is in great demand now. SMF&MMF 40G QSFP+ transceiver is designed to allow for seamless migrations from existing 10 to 40GbE network applications without requiring a redesign or expansion of the existing fiber network. And SMF&MMF QSFP+ transceiver also provides a cost-effective solution to migrate from multimode to single-mode fiber, allows a single-mode fiber infrastructure for distance up to 500m. There are several advantages of SMF&MMF 40G QSFP+ tranceiver.
SMF&MMF QSFP+ transceiver uses a duplex LC connector, which is consistent with the existing 10G connections. It allows the same cables to be used for direct 10G connections to direct 40G connections, resulting in zero-cost cabling migration. By deploying SMF&MMF 40G QSFP+ transceiver, customers increase the number of 40G links by 4 times without making any changes to their fiber infrastructure, which greatly expand network scale and performance. SMF&MMF QSFP+ transceiver interoperates with 10km QSFP-LR4 optics, it s a cost effective solution for SMF infrastructure for distances up to 500m. SMF&MMF 40G QSFP+ transceiver offers unique advantage of operating on both multimode and single-mode fiber without any requirement for additional hardware or software. Customers can consolidate their optics and use SMF&MMF QSFP+ transceivers in their network irrespective of the fiber type, which makes full use of the existing cabling systems, reduces the cost of deployment and of support, and simplify purchasing and deployments.
Conclusion
SMF&MMF 40G QSFP+ transceiver enables data centers running at 10G today to upgrade to 40G without having to re-design or modify the cable infrastructure, which allows organizations to migrate their existing 10G infrastructure to 40G at zero cost of fiber and to expand the infrastructure with low capital investment. SMF&MMF 40G QSFP+ transceiver also offers a transition path for customer planning migrations to single-mode fiber in data centers with a single transceiver that bridges the gap between multi-mode and single-mode optics. With high-density 40G switches on hand, SMF&MMF 40G QSFP+ transceiver provides a cost-effective solution for migrating to next-generation 40G data center deployments.
