Structure and polarity classification of MPO fiber patch cords

MPO (Multi-fiber Push On) fiber patch cord is composed of connectors and optical cables, and is a high-density optical fiber transmission patch cord. MPO connector is one of the MT series connectors, which is a multi-core and multi-channel plug-in connector. pin (also called PIN pin) for precise connection.

Compared with other connectors, MPO connectors are mainly characterized by compact design and large number of jumper cores. MPO connectors are the same size as SC connectors, but can accommodate 12 or 24 fibers, so MPO can greatly save cabinet wiring space. At present, MPO connectors have 8-pin, 12-pin, 24-pin, 48-pin, 72-pin, and 144-pin design, among which 12 and 24-pin MPO jumpers are more common. 40G MPO-MPO fiber jumpers generally use 12-core MPO multimode ferrules; 100G MPO-MPO fiber jumpers generally use 24-core MPO ferrules.

MPO fiber optic connectors include optical fibers, sheaths, coupling components, metal rings, pins, dust caps, etc., and the pins are divided into two forms: male and female. The male connector has two PIN pins, while the female connector does not. The connections between the MPO connectors are precisely aligned via PIN pins. When the connector is mated, a spring mounted on the end of the ferrule will provide a push to the ferrule to lock it with the adapter. There is a "key" on one side of the connector body, which is divided into "concave and convex", which is used to limit the relative position of the connector, that is, P1, P2, etc. There is a marking called "white dot" on the body side of the connector to designate the insertion side of the connector.

Generally, an optical link needs two optical fibers to complete the entire transmission process, and the polarity is the interconnection matching between the transmitting end (Tx) and the receiving end (Rx) at both ends of the optical fiber link.

MPO fiber patch cord

MPO polarity classification for three line sequences:

Type A (straight-through type): The cores at both ends of the jumper are arranged in the same position, that is, 1 at one end corresponds to 1 at the other end, and 12 at one end corresponds to 12 at the other end. The orientation of the keys on both ends is opposite, and key up corresponds to key down.

Type B (interleaved): The positions of the cores at both ends of the jumper are opposite, that is, 1 at one end corresponds to 12 at the other end, and 12 at one end corresponds to 1 at the other end. The key orientations at both ends are the same, that is, key up corresponds to key up, and key down corresponds to key down.

Type C (interleaved pair): Type C MPO jumper is a pair of adjacent cores crossed, that is, the core 1 at one end corresponds to 2 at the other end, and the core 12 at one end is 11 at the other end. The key keys at both ends are also in the opposite direction, and key up corresponds to key down.

The three polarities of connection methods and the different polar methods use different types of MPO trunk cables. However, all methods utilize duplex patch cords to form fiber optic links. The TIA standard also defines two different types of LC or SC duplex fiber optic patch cords to complete end-to-end duplex connections: A-A (crossover) patch cords and A-B (straight-through) patch cords.

Compared with other optical fiber connectors, MPO connectors have the characteristics of small size, high precision and high density. Its appearance has greatly improved the popularity of optical networks and reduced production costs. Therefore, MPO jumpers are widely used in environments that require high-density integrated optical fiber lines in the wiring process, such as FTTX, 40/100GSFP, SFP+ and other transceiver modules or connection applications inside and outside the device.