Manufacturing Process: From Fiber Insertion to Precision Polishing

The manufacturing process of an MPO connector begins with the precise cutting and insertion of optical fibers. After inserting fiber ribbons into the fiber holes of the MT ferrule, epoxy resin is used for fixation. Before epoxy curing, manufacturers such as SENKO recommend using automated fiber cleaving equipment to cleave the ferrule—a step critical for ensuring polishing quality. Automated cleaving equipment uses lasers or rotary blades to achieve a flat surface and more uniform fiber protrusion heights, significantly reducing the risk of fiber breakage compared to manual cleaving while also greatly shortening subsequent air polishing time.

Polishing is the most critical step in MPO connector manufacturing. Single-mode MPO connectors require angle polishing (APC), typically at an 8-degree angle. This design directs reflected light into the cladding, significantly reducing return loss in the fiber core. During polishing, ferrule length must be strictly controlled to avoid excessive polishing that could affect the physical contact force between ferrule end faces. According to IEC 61754-7, the unpolished flat area of an angle-polished ferrule should not exceed 0.8 mm.

The geometric parameters of the MT ferrule directly determine the connector's optical performance. Among these, Minus Side Coplanarity measures the distance between the lowest fiber in the array and the best-fit plane—the smaller the value, the better the fiber height uniformity, with an ideal value of zero. Geometry Limit (GL) is a calculated metric that evaluates the minimum normal force required to achieve physical contact, comprehensively considering ferrule angle, coplanarity, and fiber tip radius of curvature. In multimode MT ferrules, since germanium-doped fiber cores are softer, GL is a practically valuable parameter; in single-mode ferrules, however, GL is typically omitted because core depression is nearly unmeasurable.

Application Scenarios: The Cornerstone of High-Density Interconnection in AI Data Centers

The most typical application of MPO connectors in data centers is cabling systems based on the Leaf-Spine architecture. In this architecture, high-speed optical modules in servers and switching equipment commonly use MPO interfaces, and corresponding equipment patch cords, horizontal cables, and patch panels all need to support MPO connectivity.

The core components of an MPO system include horizontal cables (MPO trunk cables), MPO interface patching units, and LC interface patching units. Horizontal cables are typically multi-fiber cable assemblies pre-terminated with MPO connectors on both ends, with common fiber counts of 8, 12, 16, and 24. The panel of an MPO interface patching unit is equipped with multiple adapter strips, each integrating several MPO adapters; the MPO connectors of horizontal cables can be directly inserted into the inner side of the adapters for centralized management. LC interface patching units are configured with MPO-LC conversion modules, each capable of converting 1 to 3 MPO trunk cables into multiple LC interfaces. For example, a 12-core MPO cable can be converted into 12 LC interfaces through one module, achieving a balance between density and equipment compatibility.

The choice of equipment patch cords depends on the interface type of the network equipment. If the equipment has MPO interfaces, MPO-MPO patch cords are used; if the equipment has LC interfaces and connects to LC ports on the patch panel, LC-LC patch cords are used; if the equipment has LC interfaces but needs to connect to MPO ports on the patch panel, MPO-LC breakout patch cords are used to aggregate multiple LC devices into a single MPO port.

As 800G and 1.6T network speeds become widespread, the fiber count configuration of MPO connectors continues to evolve. Currently, 100 Gb/s per lane signaling supports 400G over 8 fibers (4 transmit, 4 receive) and 800G over 16 fibers; the upcoming IEEE 802.3dj standard will use 200 Gb/s signaling for 800G over 8 fibers and 1.6T over 16 fibers. To manage density and save space, many data centers are transitioning to Very Small Form Factor (VSFF) MPO connectors, such as US Conec's MMC connector, whose vertical stacking approach provides three times the density of traditional MPO.

Market Outlook and Technology Trends

The MPO connector market is experiencing an industrial cycle of simultaneous volume and price growth. According to Huatai Securities, the global MPO market size will grow from $1.8 billion in 2023 to $6.1 billion in 2029, representing a compound annual growth rate of 22%. Billion-dollar orders from overseas technology giants are landing密集ly—Meta signed a $6 billion order with Corning for MPO connectors and high-speed optical cables, and Nvidia reached a multi-year strategic cooperation with Corning worth up to $3.2 billion, fully validating the industry's long-term growth logic from the demand side.

The direction of technological evolution is clear: MPO ferrules are upgrading from 12 cores to 24/48/64-core high-density configurations, and evolving toward miniaturized connectors such as MMC and SN-MT. As an emerging alternative, SN-MT supports up to 16 fibers (32 fibers with dual-row ferrules), offering a smaller form factor and higher port density while maintaining compatibility with both single-mode and multimode fibers. In multimode applications, although flat polishing has traditionally been used, more and more QSFP-DD and OSFP transceiver manufacturers are recommending angle-polished multimode MPO connectors to achieve better return loss performance and system stability in high-speed PAM4 systems.