How to Use Universal Polarity MTP® Fiber Cassette

Posted on Jun 21, 2023

Fiber polarity is a crucial aspect of any fiber network. Simply put, polarity refers to the signal transmitted by a fiber optic link at one end of the cable matching the corresponding receiver at the other end. While this concept may seem simple, it becomes more complex with multifiber cables and MTP®/MPO connectors. Universal polarity MTP®/MPO fiber cassette is the suitable solution to solve this question.

Why Use Universal Polarity Fiber Cassettes

Compared to the previous fiber polarity methods A, B & C, universal polarity provides an easier way to manage polarity. Methods A and B require different components, patch cables and cassettes respectively. Method C allows for the use of singular patch cables and cassettes but is not flexible for migration or direct transceiver connect applications. Universal polarity fiber cassettes to be used at both ends of a Method B MTP®/MPO trunk reduces the complexity of a fiber network, ensuring consistent MTP®/MPO polarity, and streamlining network maintenance. The following chart provides a simple explanation of the differences between the 4 general fiber polarity methods:

Method A
Method B
Method C
Straight Through
Ferrule Flipped
Ferrule Flipped
Pair Flipped
Fiber Patch Cables

FHD® (FS High Density) MTP® cassettes also use US Conec MTP® adapters and Corning fiber, while LC ports adopt zirconia ceramic sleeves to ensure consistent low loss. This blog post provides information on Universal Polarity in MTP® Cabling Systems.

Application of Universal Polarity MTP® Cassettes

Universal polarity MTP® cassettes with 8, 12 or 24 fibers are widely used for managing fiber cables in data centers or enterprise cabling. FS launched universal polarity MTP®/MPO cassettes with 8, 12, or 24 fibers to simplify the duplex fiber polarity management for technicians. The following two examples show 25G to 25G connection and 40G to 10G breakout application with FS MTP®/MPO universal polarity optical cassettes.

12 Fiber MTP® Cassette in 25G Connection

Figure 1 shows a 25G to 25G connection by FS universal polarity MTP®/MPO to LC fiber cassettes, 25G network switches, SFP28 fiber transceivers, MTP® cables and LC fiber patch cables. The two 25G fiber switches are deployed separately on site A and site B. And 25G transceivers are plugged into the switches for linking LC single mode fiber patch cables (A to B polarity). Then, the LC fiber patch cables on two sides are connected to universal polarity MTP®/MPO 12 to LC cassettes installed on each fiber enclosure. And one MTP® type B OS2 fiber is used to connect the two MTP®-12 cassettes. In this way, it allows the same patch cables and cassettes to be deployed on both ends, which simply helps network cabling deployment while ensuring consistent MTP®/MPO polarity.



Figure 1 MTP®-12 cassette used in 25G trunk cabling

8 Fiber MTP® Cassette in 40G to 10G Connection

The MTP®-8 cassette features one rear 8-fiber MTP® port connection and 4 duplex LC ports in the front. As shown in the following figure, the cabling solution deploys a type B MTP® trunk cable connected to 40G transceiver on a 40G data center switch on one end of the link. LC to LC single mode patch cables connected to a 10G switch via SFP+ transceiver on the other end. With this flexible cabling, one can step down 40G channels to 10G channels as needed. Please check in Base-8 MTP®/MPO Cabling Solutions for 10G/25G/40G/100G to get more information.



Figure 2 MTP®-8 cassette used in 40G to 10G connection

The MTP® cassettes can also be mounted in FHD® series rack enclosures or wall mount enclosures. Installed on an FHD® fiber enclosure, four MTP®-8 to LC cassettes can route up to 32 fiber connections in a 1U rack. Four MTP®-12 to LC cassettes can route up to 48 fiber connections, making them ideal for high-density cabling in data centers or telecom rooms.


The universal polarity fiber cassette is an easier option for cabling management, installation, and end-user connectivity. It allows the same patch cables and cassettes to be used at each end of the channel. In addition, mixing fiber polarity types may work in some cases, but detailed planning, evaluation, and validation are required. Please do not mix the MTP®/MPO fiber polarity types to ensure proper signaling throughout the installation.

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