Recently, a topic about SMF and MMF is hot in the forum. And lots of people have expressed their own views, which can be checked in this link: single-mode fiber vs multimode implementation recommendations and cost difference. From the reddit post, we can summarize that the optics for single-mode are more expensive than optics for multimode. But the single-mode fiber itself is usually significantly cheaper. And lots of data centers and providers will only do single-mode cabling for new installs. So this post will have a comparison between single-mode optics and multimode optics from the following cost perspectives.

System Cost

To utilize the fundamental attributes of single-mode fibers, which are generally geared towards longer distance applications, requires transceivers with lasers that operate at longer wavelengths with smaller spot-size and generally narrower spectral width. These transceiver characteristics combined with the need for higher-precision alignment and tighter connector tolerances to smaller core diameters result in significantly higher transceiver costs and overall higher interconnect costs for singe-mode fiber interconnects.

Fabrication methods for VCSEL based transceivers that are optimized for use with multimode fibers are more easily manufactured into array devices and are lower cost than equivalent single-mode transceivers. Despite the use of multiple fiber lanes and multi-transceivers arrays, there are significant cost saving over single-mode technology employing single or multichannel operation over simplex-duplex connectivity. Multimode fiber system offers the lowest system cost and upgrade path to 100G for standard-based premises applications using parallel-optic based interconnects.

Installation Cost

Single-mode fiber often costs less than multimode fiber. When building a 1G fiber optic network that you want to be able to go to 10G or faster on eventually, the savings on cost of fiber for single-mode saves about half-price. While the OM3 or OM4 multimode increase 35% in cost for SFPs. The single-mode optics are more expensive, but the labor costs of replacing the multimode are significantly higher, especially if those followed OM1—OM2—OM3—OM4. If you are willing to look at used ex-fiberchannel SFPs, the price of single-mode 1G drops through the floor. If you have budget and need for 10G short connections, the economics at last check still support multimode. Keep an eye on those economics though, as history suggests that the price premium for single-mode will drop.

Conclusion

This post has had a simple comparison between the single-mode optics and multimode optics from three different perspectives. Both single-mode optics and multimode optics have their own features. Single-mode fiber cabling system is suitable for long-reach data transmission applications and widely deployed in carrier networks, MANs and PONs. Multimode fiber cabling system has a shorter reach and is widely deployed in enterprise data centers and LANs. No matter single-mode system or multimode system, you should choose the one that best suits your network demands.