MTP Polarity

MTP polarity refers to the arrangement of optical fibers in an optical link. In a normal working link, two optical fibers are involved, the transmit (TX) and receive (RX), so if you want to establish a link that can work properly, you must ensure that the transmit fiber matches the received fiber.

MTP connectors are multi-fiber connectors that usually accommodate 12 or 24 optical fibers in a single sleeve. The connector has alignment pins to ensure that the fibers are properly aligned when connected. The optical fibers in MTP connectors are numbered, usually from left to right.

Polarization Methods of MTP Cable

There are three standardized polarity methods to ensure that the MTP fiber maintains the correct polarity: straight-through, reverse, and flip. Each method can ensure that the fiber is properly aligned and the connection is reliable. Next, I will introduce these three methods to you.

Type A (Straight-through)

In type A, the fiber is connected in a straight-through manner, and the object of the fiber connection will be determined according to the position number of the fiber. For example, fiber 1 of key up is connected to fiber 1 of key down, fiber 2 is connected to fiber 2, and so on. The advantage of this is that it is easy to use and is widely used in a variety of connections. It is also simple to deploy and is more suitable for deploying long fiber lines. Finally, it is also compatible with LC duplex patch cords and can be connected to existing networks.

Type B (Reversed)

Type B is the opposite of Type A. The optical fiber needs to be reversed in the connector, that is, the key-up optical fiber 1 is connected to the key-down optical fiber 12, and the optical fiber 2 is connected to the optical fiber 11. It uses B-type patch cords at both ends to achieve optical fiber connectivity. This can effectively simplify patch cord management because both ends are of the same type and are easier to deploy. However, it is not compatible with duplex cables and does not have wide compatibility.

Type C (Pairwise Flip)

Type C is completely different from the previous two methods. Each pair of optical fibers needs to be reversed, but the connectors are not completely flipped. The connection is made by connecting key up optical fiber 1 to key down optical fiber 2, and key down optical fiber 1 to key up optical fiber 2. Although this method can be connected with LC duplex patch cords, it is difficult to use in high-density environments and is very rare.

Why is Polarity Important

In fiber optic communications, data is transmitted using pulses of light from a single optical fiber. In order for data to be transmitted properly, the transmitting and receiving ends of the optical fiber must be matched to ensure that data can pass properly. In an MTP connector, multiple optical fibers are installed in one connector, and the multiple optical fibers have more complex polarities than a single optical fiber connected to each other. Incorrect polarity can cause an unstable connection, resulting in data loss, signal degradation, or the failure of data packets to be transmitted to the destination.

Conclusion

Understanding MTP polarity is essential to ensure reliability and efficient fiber connections in high-density network environments. Through three standardized methods, the polarity of the optical fiber can be properly aligned to ensure normal data transmission at the transmitting and receiving ends. You can choose any of the three methods to deploy according to your needs, so that the devices at both ends can be effectively connected. If you have any questions about MTP polarity, please feel free to contact QSFPTEK's CCIE/HCIE engineers at [email protected].