How to Choose The Right MPO/MTP Trunk Cable?

MPO/MTP trunk cable is popular in the fiber optic market, especially for high-density application like data center, since it will save much space hence saving a lot of cost. Then how to choose the right MPO/MTP trunk cable for your project?

1.  MPO Connector or MTP Connector?

MTP is a brand name for an MPO connector developed by US Conec. It conforms to MPO specs. Some people prefers MTP. In my opinion, MTP or MPO is not a question. I know that MTP stands for good quality for some people. But actually MPO connector is also good and with much low cost. What you should pay more attention to is that standard loss or low loss. Standard loss means insert loss <0.75db for single mode and multimode, low loss means insert loss <0.35db for single-mode and multimode. Both MTP and MPO connectors can achieve it.

2.  Multimode or Single-Mode?

It depends on Transmission distance, if it is a long-distance, you have to choose single mode.

Multimode is only for a short distance. For 10Gbit/s, OM3 fiber supports 100m, OM4 fiber supports 150m.

Single-mode is also can be used in short distance. But the single mode device/equipments are more expensive. So on the whole, multimode is a better choice for short distance.

3.  Fibre count

There are many options, 8fibre or 12 fibers, 24 fibers, 36 fibers, 48 fibers,72 fiber,96 fibers, 144 fibers.

It depends on your detail requirement.

If used to connect two QSFP+ 40G module, normally it is 8 fiber.

4.  Polarity

There are 3 types of MPO trunk cable, called Polarity A, Polarity B, Polarity C. No matter which type is chosen, must make sure that the transmitter Chanel is linked to the receiver channel.

MPO Trunk Cable Polarity A: Polarity A cable is also known as straight cable, is a straight-through cable with a key up MPO connector on one end and a key down MPO connector on another end. It makes the fibers at the same fiber position on each end. Just as picture below you see, the fiber located at position 1 (P1) of the connector on one side link with P1 at the other connector.

MPO Trunk Cable Polarity B: Polarity B cable, also known as reversed cable, uses key up connector on both ends of the cable. This type of array mating results in an inversion, which means the fiber positions are reversed at each end. The fiber at P1 at one end is linked with fiber at P12 at the another end. Just as the picture below.

MPO Trunk Cable Polarity C: Polarity C cable (pairs flipped cable) is similar to Polarity A cable, one key up connector link with one key down connector. However, in Polarity C each adjacent pair of fibers at one end are flipped at the other end. The fiber at position 1 on one end is shifted to position 2 at the other end of the cable. The fiber at position 2 at one end is shifted to position 1 at the opposite end.

5. Armoured or Not Armoured?

Most MPO/MTP trunk cable are not armoured for indoor application. Armored is more expensive and not so flexible. Armoured is aiming to protect fiber from biting. If no rodent visits the room where MPO/MTP trunk cable deployed, then armoured is not needed. For outdoor application, armoured is recommended.

6.  Female or Male?

MPO connectors can be either male (with two guide pins) or female (without pins but with 2 holes). MPO cables can only be connected male to female. QSFP+ and QSFP28 transceivers require MPO cables for connection. The international standard states that transceivers should have male ports and require a female MPO connector.

If it is mated with adapter, there must be one male connector mate another female connector.

No matter MTP or MPO, you can pull out/push in the pin, then male or female can be changed.

7.  Indoor or outdoor

Normally MPO trunk cable is used in the indoor application, but if it is used in an outdoor application, then must choose the outdoor cable and assemble waterproof connector.

Below is a popular armoured cable used for MPO trunk cable.

Below is a popular ODVA connector with MPO connector inbuilt.